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Diffstat (limited to 'lib/sasl/doc/src/release_handler.xml')
| -rw-r--r-- | lib/sasl/doc/src/release_handler.xml | 743 |
1 files changed, 396 insertions, 347 deletions
diff --git a/lib/sasl/doc/src/release_handler.xml b/lib/sasl/doc/src/release_handler.xml index 692159d7bf..162707676c 100644 --- a/lib/sasl/doc/src/release_handler.xml +++ b/lib/sasl/doc/src/release_handler.xml @@ -31,109 +31,115 @@ <module>release_handler</module> <modulesummary>Unpacking and Installation of Release Packages</modulesummary> <description> - <p>The <em>release handler</em> is a process belonging to the SASL - application which is responsible for <em>release handling</em>, + <p>The <em>release handler</em> process belongs to the <c>SASL</c> + application, which is responsible for <em>release handling</em>, that is, unpacking, installation, and removal of release packages.</p> - <p>An introduction to release handling and a usage example can be - found in - <seealso marker="doc/design_principles:release_handling">Design Principles</seealso>. - </p> + <p>An introduction to release handling and an example is provided in + <seealso marker="doc/design_principles:release_handling">OTP Design + Principles</seealso> in <em>System Documentation</em>.</p> <p>A <em>release package</em> is a compressed tar file containing code for a certain version of a release, created by calling - <seealso marker="systools#make_tar/1">systools:make_tar/1,2</seealso>. - The release package should be placed in the <c>$ROOT/releases</c> - directory of the previous version of the release where + <seealso marker="systools#make_tar/1"><c>systools:make_tar/1,2</c></seealso>. + The release package is to be located in the <c>$ROOT/releases</c> + directory of the previous version of the release, where <c>$ROOT</c> is the installation root directory, - <c>code:root_dir()</c>. - Another <c>releases</c> directory can be specified using the SASL - configuration parameter <c>releases_dir</c>, or the OS environment + <seealso marker="kernel:code#root_dir/0"><c>code:root_dir()</c></seealso>. + Another <c>releases</c> directory can be specified using the <c>SASL</c> + configuration parameter <c>releases_dir</c> or the OS environment variable <c>RELDIR</c>. The release handler must have write access - to this directory in order to install the new release. + to this directory to install the new release. The persistent state of the release handler is stored there in a file called <c>RELEASES</c>.</p> - <p>A release package should always contain the release resource file - <c>Name.rel</c> and a boot script <c>Name.boot</c>. It may contain - a release upgrade file <c>relup</c> and a system configuration - file <c>sys.config</c>. The <c>.rel</c> file contains information - about the release: its name, version, and which ERTS and - application versions it uses. The <c>relup</c> file contains - scripts for how to upgrade to, or downgrade from, this version of - the release.</p> + <p>A release package is always to contain:</p> + <list type="bulleted"> + <item>A release resource file, <c>Name.rel</c></item> + <item>A boot script, <c>Name.boot</c></item> + </list> + <p>The <c>.rel</c> file contains information about the release: its name, + version, and which <c>ERTS</c> and application versions it uses.</p> + <p>A release package can also contain:</p> + <list type="bulleted"> + <item>A release upgrade file, <c>relup</c></item> + <item>A system configuration file, <c>sys.config</c></item> + </list> + <p>The <c>relup</c> file contains instructions for how to upgrade + to, or downgrade from, this version of the release.</p> <p>The release package can be <em>unpacked</em>, which extracts the files. An unpacked release can be <em>installed</em>. The currently used version of the release is then upgraded or downgraded to the specified version by evaluating the instructions - in <c>relup</c>. An installed release can be made - <em>permanent</em>. There can only be one permanent release in - the system, and this is the release that is used if the system + in the <c>relup</c> file. An installed release can be made + <em>permanent</em>. Only one permanent release can exist in + the system, and this release is used if the system is restarted. An installed release, except the permanent one, can be <em>removed</em>. When a release is removed, all files - that belong to that release only are deleted.</p> - <p>Each version of the release has a status. The status can be + belonging to that release only are deleted.</p> + <p>Each release version has a status, which can be <c>unpacked</c>, <c>current</c>, <c>permanent</c>, or <c>old</c>. - There is always one latest release which either has status - <c>permanent</c> (normal case), or <c>current</c> (installed, but - not yet made permanent). The following table illustrates - the meaning of the status values:</p> + There is always one latest release, which either has status + <c>permanent</c> (normal case) or <c>current</c> (installed, but + not yet made permanent). The meaning of the status values are + illustrated in the following table:</p> <pre> -Status Action NextStatus -------------------------------------------- - - unpack unpacked -unpacked install current - remove - -current make_permanent permanent - install other old - remove - -permanent make other permanent old - install permanent -old reboot_old permanent - install current - remove - - </pre> + Status Action NextStatus + ------------------------------------------- + - unpack unpacked + unpacked install current + remove - + current make_permanent permanent + install other old + remove - + permanent make other permanent old + install permanent + old reboot_old permanent + install current + remove -</pre> <p>The release handler process is a locally registered process on each node. When a release is installed in a distributed system, the release handler on each node must be called. The release - installation may be synchronized between nodes. From an operator - view, it may be unsatisfactory to specify each node. The aim is + installation can be synchronized between nodes. From an operator + view, it can be unsatisfactory to specify each node. The aim is to install one release package in the system, no matter how many - nodes there are. If this is the case, it is recommended that - software management functions are written which take care of - this problem. Such a function may have knowledge of the system + nodes there are. It is recommended that + software management functions are written that take care of + this problem. Such a function can have knowledge of the system architecture, so it can contact each individual release handler to install the package.</p> - <p>For release handling to work properly, the runtime system needs - to have knowledge about which release it is currently running. It - must also be able to change (in run-time) which boot script and - system configuration file should be used if the system is + <p>For release handling to work properly, the runtime system must + know which release it is running. It + must also be able to change (in runtime) which boot script and + system configuration file are to be used if the system is restarted. This is taken care of automatically if Erlang is - started as an embedded system. Read about this in <em>Embedded System</em>. In this case, the system configuration file - <c>sys.config</c> is mandatory.</p> - <p>The installation of a new release may restart the system. Which - program to use is specified by the SASL configuration - parameter <c>start_prg</c> which defaults + started as an embedded system. Read about this in + <seealso marker="doc/embedded:users_guide">Embedded System</seealso> in + <em>System Documentation</em>. In this case, the system + configuration file <c>sys.config</c> is mandatory.</p> + <p>The installation of a new release can restart the system. Which + program to use is specified by the <c>SASL</c> configuration + parameter <c>start_prg</c>, which defaults to <c>$ROOT/bin/start</c>.</p> <p>The emulator restart on Windows NT expects that the system is started using the <c>erlsrv</c> program (as a service). - Furthermore the release handler expects that the service is named - <em>NodeName</em>_<em>Release</em>, where <em>NodeName</em> is - the first part of the Erlang nodename (up to, but not including - the "@") and <em>Release</em> is the current version of - the release. The release handler furthermore expects that a + Furthermore, the release handler expects that the service is named + <c>NodeName</c>_<c>Release</c>, where <c>NodeName</c> is + the first part of the Erlang node name (up to, but not including + the "@") and <c>Release</c> is the current release version. + The release handler furthermore expects that a program like <c>start_erl.exe</c> is specified as "machine" to - <c>erlsrv</c>. During upgrading with restart, a new service will - be registered and started. The new service will be set to - automatic and the old service removed as soon as the new release + <c>erlsrv</c>. During upgrading with restart, a new service + is registered and started. The new service is set to + automatic and the old service is removed when the new release is made permanent.</p> - <p>The release handler at a node which runs on a diskless machine, + <p>The release handler at a node running on a diskless machine, or with a read-only file system, must be configured accordingly - using the following <c>sasl</c> configuration parameters (see - <seealso marker="sasl_app">sasl(6)</seealso> for details):</p> + using the following <c>SASL</c> configuration parameters (for + details, see <seealso marker="sasl_app">sasl(6)</seealso>):</p> <taglist> <tag><c>masters</c></tag> <item> - <p>This node uses a number of master nodes in order to store - and fetch release information. All master nodes must be up - and running whenever release information is written by this + <p>This node uses some master nodes to store + and fetch release information. All master nodes must be + operational whenever release information is written by this node.</p> </item> <tag><c>client_directory</c></tag> @@ -145,24 +151,25 @@ old reboot_old permanent <item> <p>This parameter specifies if the Erlang emulator is statically installed at the client node. A node with a static - emulator cannot dynamically switch to a new emulator because + emulator cannot dynamically switch to a new emulator, as the executable files are statically written into memory.</p> </item> </taglist> - <p>It is also possible to use the release handler to unpack and + <p>The release handler can also be used to unpack and install release packages when not running Erlang as an embedded - system, but in this case the user must somehow make sure that + system. However, in this case the user must somehow ensure that correct boot scripts and configuration files are used if - the system needs to be restarted.</p> - <p>There are additional functions for using another file structure + the system must be restarted.</p> + <p>Functions are provided for using another file structure than the structure defined in OTP. These functions can be used to test a release upgrade locally.</p> </description> + <funcs> <func> <name>check_install_release(Vsn) -> {ok, OtherVsn, Descr} | {error, Reason}</name> <name>check_install_release(Vsn,Opts) -> {ok, OtherVsn, Descr} | {error, Reason}</name> - <fsummary>Check installation of a release in the system.</fsummary> + <fsummary>Checks installation of a release in the system.</fsummary> <type> <v>Vsn = OtherVsn = string()</v> <v>Opts = [Opt]</v> @@ -173,27 +180,29 @@ old reboot_old permanent <desc> <p>Checks if the specified version <c>Vsn</c> of the release can be installed. The release must not have status - <c>current</c>. Issues warnings if <c>relup</c> or - <c>sys.config</c> are not present. If <c>relup</c> is present, + <c>current</c>. Issues warnings if <c>relup</c> file or + <c>sys.config</c> is not present. If <c>relup</c> file is present, its contents are checked and <c>{error,Reason}</c> is returned if an error is found. Also checks that all required - applications are present and that all new code can be loaded, - or <c>{error,Reason}</c> is returned.</p> - <p>This function evaluates all instructions that occur before + applications are present and that all new code can be loaded; + <c>{error,Reason}</c> is returned if an error is found.</p> + <p>Evaluates all instructions that occur before the <c>point_of_no_return</c> instruction in the release upgrade script.</p> - <p>Returns the same as <c>install_release/1</c>. <c>Descr</c> - defaults to "" if no <c>relup</c> file is found.</p> - <p>If the option <c>purge</c> is given, all old code that can - be soft purged will be purged after all other checks are - successfully completed. This can be useful in order to + <p>Returns the same as + <seealso marker="#install_release/1"><c>install_release/1</c></seealso>. + <c>Descr</c> defaults to "" if no <c>relup</c> file is found.</p> + <p>If option <c>purge</c> is specified, all old code that can + be soft-purged is purged after all other checks are + successfully completed. This can be useful to reduce the time needed by <seealso - marker="#install_release/1">install_release</seealso>.</p> + marker="#install_release/1"><c>install_release/1</c></seealso>.</p> </desc> </func> + <func> <name>create_RELEASES(Root, RelDir, RelFile, AppDirs) -> ok | {error, Reason}</name> - <fsummary>Create an initial RELEASES file.</fsummary> + <fsummary>Creates an initial <c>RELEASES</c> file.</fsummary> <type> <v>Root = RelDir = RelFile = string()</v> <v>AppDirs = [{App, Vsn, Dir}]</v> @@ -202,52 +211,55 @@ old reboot_old permanent <v>Reason = term()</v> </type> <desc> - <p>Creates an initial RELEASES file to be used by the release - handler. This file must exist in order to install new + <p>Creates an initial <c>RELEASES</c> file to be used by the + release handler. This file must exist to install new releases.</p> <p><c>Root</c> is the root of the installation (<c>$ROOT</c>) as - described above. <c>RelDir</c> is the the directory where - the <c>RELEASES</c> file should be created (normally + described earlier. <c>RelDir</c> is the directory where + the <c>RELEASES</c> file is to be created (normally <c>$ROOT/releases</c>). <c>RelFile</c> is the name of the <c>.rel</c> file that describes the initial release, including the extension <c>.rel</c>.</p> <p><c>AppDirs</c> can be used to specify from where the modules - for the specified applications should be loaded. <c>App</c> is + for the specified applications are to be loaded. <c>App</c> is the name of an application, <c>Vsn</c> is the version, and <c>Dir</c> is the name of the directory where <c>App-Vsn</c> - is located. The corresponding modules should be located under + is located. The corresponding modules are to be located under <c>Dir/App-Vsn/ebin</c>. The directories for applications not specified in <c>AppDirs</c> are assumed to be located in <c>$ROOT/lib</c>.</p> </desc> </func> + <func> <name>install_file(Vsn, File) -> ok | {error, Reason}</name> - <fsummary>Install a release file in the release structure.</fsummary> + <fsummary>Installs a release file in the release structure.</fsummary> <type> <v>Vsn = File = string()</v> <v>Reason = term()</v> </type> <desc> - <p>Installs a release dependent file in the release structure. - A release dependent file is a file that must be in + <p>Installs a release-dependent file in the release structure. + The release-dependent file must be in the release structure when a new release is installed: - <c>start.boot</c>, <c>relup</c> and <c>sys.config</c>.</p> + <c>start.boot</c>, <c>relup</c>, and <c>sys.config</c>.</p> <p>The function can be called, for example, when these files - are generated at the target. It should be called after - <c>set_unpacked/2</c> has been called.</p> + are generated at the target. The function is to be called after + <seealso marker="#set_unpacked/2"><c>set_unpacked/2</c></seealso> + has been called.</p> </desc> </func> + <func> <name>install_release(Vsn) -> {ok, OtherVsn, Descr} | {error, Reason}</name> <name>install_release(Vsn, [Opt]) -> {ok, OtherVsn, Descr} | {continue_after_restart, OtherVsn, Descr} | {error, Reason}</name> - <fsummary>Install a release in the system.</fsummary> + <fsummary>Installs a release in the system.</fsummary> <type> <v>Vsn = OtherVsn = string()</v> <v>Opt = {error_action, Action} | {code_change_timeout, Timeout}</v> <v> | {suspend_timeout, Timeout} | {update_paths, Bool}</v> <v> Action = restart | reboot</v> - <v> Timeout = default | infinity | int()>0</v> + <v> Timeout = default | infinity | pos_integer()</v> <v> Bool = boolean()</v> <v>Descr = term()</v> <v>Reason = {illegal_option, Opt} | {already_installed, Vsn} | {change_appl_data, term()} | {missing_base_app, OtherVsn, App} | {could_not_create_hybrid_boot, term()} | term()</v> @@ -262,7 +274,7 @@ old reboot_old permanent version and a script <c>{Vsn,Descr2,Instructions2}</c> in this file for downgrading to <c>Vsn</c>.</p> <p>If a script is found, the first thing that happens is that - the applications specifications are updated according to + the application specifications are updated according to the <c>.app</c> files and <c>sys.config</c> belonging to the release version <c>Vsn</c>.</p> <p>After the application specifications have been updated, @@ -271,101 +283,120 @@ old reboot_old permanent <c>OtherVsn</c> and <c>Descr</c> are the version (<c>UpFromVsn</c> or <c>Vsn</c>) and description (<c>Descr1</c> or <c>Descr2</c>) as specified in the script.</p> - <p>If <c>{continue_after_restart,OtherVsn,Descr}</c> is - returned, it means that the emulator will be restarted - before the upgrade instructions are executed. This will - happen if the emulator or any of the applications kernel, - stdlib or sasl are updated. The new version of the emulator - and these core applications will execute after the restart, - but for all other applications the old versions will be - started and the upgrade will be performed as normal by + <p>If <c>{continue_after_restart,OtherVsn,Descr}</c> is + returned, the emulator is restarted + before the upgrade instructions are executed. This + occurs if the emulator or any of the applications + <c>Kernel</c>, <c>STDLIB</c>, or <c>SASL</c> + are updated. The new emulator version + and these core applications execute after the restart. + For all other applications the old versions are + started and the upgrade is performed as normal by executing the upgrade instructions.</p> <p>If a recoverable error occurs, the function returns <c>{error,Reason}</c> and the original application specifications are restored. If a non-recoverable error occurs, the system is restarted.</p> - <p>The option <c>error_action</c> defines if the node should be - restarted (<c>init:restart()</c>) or rebooted - (<c>init:reboot()</c>) in case of an error during - the installation. Default is <c>restart</c>.</p> - <p>The option <c>code_change_timeout</c> defines the timeout - for all calls to <c>sys:change_code</c>. If no value is - specified or <c>default</c> is given, the default value - defined in <c>sys</c> is used.</p> - <p>The option <c>suspend_timeout</c> defines the timeout for - all calls to <c>sys:suspend</c>. If no value is specified, - the values defined by the <c>Timeout</c> parameter of - the <c>upgrade</c> or <c>suspend</c> instructions are used. - If <c>default</c> is specified, the default value defined in - <c>sys</c> is used.</p> - <p>The option <c>{update_paths,Bool}</c> indicates if all - application code paths should be updated (<c>Bool==true</c>), - or if only code paths for modified applications should be - updated (<c>Bool==false</c>, default). This option only has - effect for other application directories than the default - <c>$ROOT/lib/App-Vsn</c>, that is, application directories - provided in the <c>AppDirs</c> argument in a call to - <c>create_RELEASES/4</c> or <c>set_unpacked/2</c>.</p> - <p>Example: In the current version <c>CurVsn</c> of a release, - the application directory of <c>myapp</c> is - <c>$ROOT/lib/myapp-1.0</c>. A new version <c>NewVsn</c> is - unpacked outside the release handler, and the release handler - is informed about this with a call to:</p> - <code type="none"> + <p><em>Options</em>:</p> + <taglist> + <tag><c>error_action</c></tag> + <item><p>Defines if the node is to be + restarted + (<seealso marker="erts:init#restart/0"><c>init:restart()</c></seealso>) + or rebooted + (<seealso marker="erts:init#reboot/0"><c>init:reboot()</c></seealso>) + if there is an error during + the installation. Default is <c>restart</c>.</p></item> + <tag><c>code_change_timeout</c></tag> + <item><p>Defines the time-out + for all calls to + <seealso marker="stdlib:sys#change_code/4"><c>stdlib:sys:change_code</c></seealso>. + If no value is specified or <c>default</c> is specified, the + default value defined in <c>sys</c> is used.</p></item> + <tag><c>suspend_timeout</c></tag> + <item><p>Defines the time-out for + all calls to + <seealso marker="stdlib:sys#suspend/1"><c>stdlib:sys:suspend</c></seealso>. + If no value is specified, the values defined by the <c>Timeout</c> + parameter of the <c>upgrade</c> or <c>suspend</c> instructions are used. + If <c>default</c> is specified, the default value defined in + <c>sys</c> is used.</p></item> + <tag><c>{update_paths,Bool}</c></tag> + <item><p>Indicates if all + application code paths are to be updated (<c>Bool==true</c>) + or if only code paths for modified applications are to be + updated (<c>Bool==false</c>, default). This option has only + effect for other application directories than the default + <c>$ROOT/lib/App-Vsn</c>, that is, application directories + specified in argument <c>AppDirs</c> in a call to + <seealso marker="#create_RELEASES/4"><c>create_RELEASES/4</c></seealso> or + <seealso marker="#set_unpacked/2"><c>set_unpacked/2</c></seealso>.</p> + <p><em>Example:</em></p> + <p>In the current version <c>CurVsn</c> of a release, the + application directory of <c>myapp</c> is + <c>$ROOT/lib/myapp-1.0</c>. A new version <c>NewVsn</c> is + unpacked outside the release handler and the release + handler is informed about this with a call as follows:</p> + <code type="none"> release_handler:set_unpacked(RelFile, [{myapp,"1.0","/home/user"},...]). -=> {ok,NewVsn} - </code> - <p>If <c>NewVsn</c> is installed with the option - <c>{update_paths,true}</c>, afterwards - <c>code:lib_dir(myapp)</c> will return - <c>/home/user/myapp-1.0</c>.</p> +=> {ok,NewVsn}</code> + <p>If <c>NewVsn</c> is installed with option + <c>{update_paths,true}</c>, then + <seealso marker="kernel:code#lib_dir/1"><c>kernel:code:lib_dir(myapp)</c></seealso> + returns <c>/home/user/myapp-1.0</c>.</p></item> + </taglist> <note> - <p>Installing a new release might be quite time consuming if + <p>Installing a new release can be time consuming if there are many processes in the system. The reason is that each process must be checked for references to old code - before a module can be purged. This check might lead to + before a module can be purged. This check can lead to garbage collections and copying of data.</p> - <p>If you wish to speed up the execution of - <c>install_release</c>, then you may call <seealso - marker="#check_install_release/1">check_install_release</seealso> - first, using the option <c>purge</c>. This will do the same - check for old code, and then purge all modules that can be - soft purged. The purged modules will then no longer have any - old code, and <c>install_release</c> will not need to do the + <p>To speed up the execution of + <seealso marker="#install_release/1"><c>install_release</c></seealso>, + first call <seealso + marker="#check_install_release/1"><c>check_install_release</c></seealso>, + using option <c>purge</c>. This does the same + check for old code. Then purges all modules that can be + soft-purged. The purged modules do then no longer have any + old code, and + <seealso marker="#install_release/1"><c>install_release</c></seealso> + does not need to do the checks.</p> - <p>Obviously, this will not reduce the overall time for the - upgrade, but it will allow checks and purge to be executed + <p>This does not reduce the overall time for the + upgrade, but it allows checks and purge to be executed in the background before the real upgrade is started.</p> </note> <note> <p>When upgrading the emulator from a version older than OTP - R15, there will be an attempt to load new application beam - code into the old emulator. In some cases, the new beam - format can not be read by the old emulator, and so the code - loading will fail and terminate the complete upgrade. To - overcome this problem, the new application code should be - compiled with the old emulator. See <seealso - marker="doc/design_principles:appup_cookbook">Design - Principles</seealso> for more information about emulator - upgrade from pre OTP R15 versions.</p> + R15, an attempt is made to load new application beam + code into the old emulator. Sometimes the new beam + format cannot be read by the old emulator, so the code + loading fails and the complete upgrade is terminated. To + overcome this problem, the new application code is to be + compiled with the old emulator. For more information about + emulator upgrade from pre OTP R15 versions, see + <seealso marker="doc/design_principles:appup_cookbook">Design + Principles</seealso> in <em>System Documentation</em>.</p> </note> </desc> </func> + <func> <name>make_permanent(Vsn) -> ok | {error, Reason}</name> - <fsummary>Make the specified release version permanent.</fsummary> + <fsummary>Makes the specified release version permanent.</fsummary> <type> <v>Vsn = string()</v> <v>Reason = {bad_status, Status} | term()</v> </type> <desc> - <p>Makes the specified version <c>Vsn</c> of the release + <p>Makes the specified release version <c>Vsn</c> permanent.</p> </desc> </func> + <func> <name>remove_release(Vsn) -> ok | {error, Reason}</name> - <fsummary>Remove a release from the system.</fsummary> + <fsummary>Removes a release from the system.</fsummary> <type> <v>Vsn = string()</v> <v>Reason = {permanent, Vsn} | client_node | term()</v> @@ -375,23 +406,26 @@ release_handler:set_unpacked(RelFile, [{myapp,"1.0","/home/user"},...]). The release must not be the permanent release. Removes only the files and directories not in use by another release.</p> </desc> + </func> <func> <name>reboot_old_release(Vsn) -> ok | {error, Reason}</name> - <fsummary>Reboot the system from an old release.</fsummary> + <fsummary>Reboots the system from an old release.</fsummary> <type> <v>Vsn = string()</v> <v>Reason = {bad_status, Status} | term()</v> </type> <desc> <p>Reboots the system by making the old release permanent, and - calls <c>init:reboot()</c> directly. The release must have - status <c>old</c>.</p> + calls + <seealso marker="erts:init#reboot/0"><c>init:reboot()</c></seealso> + directly. The release must have status <c>old</c>.</p> </desc> </func> + <func> <name>set_removed(Vsn) -> ok | {error, Reason}</name> - <fsummary>Mark a release as removed.</fsummary> + <fsummary>Marks a release as removed.</fsummary> <type> <v>Vsn = string()</v> <v>Reason = {permanent, Vsn} | term()</v> @@ -403,9 +437,10 @@ release_handler:set_unpacked(RelFile, [{myapp,"1.0","/home/user"},...]). not delete any files.</p> </desc> </func> + <func> <name>set_unpacked(RelFile, AppDirs) -> {ok, Vsn} | {error, Reason}</name> - <fsummary>Mark a release as unpacked.</fsummary> + <fsummary>Marks a release as unpacked.</fsummary> <type> <v>RelFile = string()</v> <v>AppDirs = [{App, Vsn, Dir}]</v> @@ -419,18 +454,19 @@ release_handler:set_unpacked(RelFile, [{myapp,"1.0","/home/user"},...]). the release is unpacked. <c>Vsn</c> is extracted from the release resource file <c>RelFile</c>.</p> <p><c>AppDirs</c> can be used to specify from where the modules - for the specified applications should be loaded. <c>App</c> is + for the specified applications are to be loaded. <c>App</c> is the name of an application, <c>Vsn</c> is the version, and <c>Dir</c> is the name of the directory where <c>App-Vsn</c> - is located. The corresponding modules should be located under + is located. The corresponding modules are to be located under <c>Dir/App-Vsn/ebin</c>. The directories for applications not specified in <c>AppDirs</c> are assumed to be located in <c>$ROOT/lib</c>.</p> </desc> </func> + <func> <name>unpack_release(Name) -> {ok, Vsn} | {error, Reason}</name> - <fsummary>Unpack a release package.</fsummary> + <fsummary>Unpacks a release package.</fsummary> <type> <v>Name = Vsn = string()</v> <v>Reason = client_node | term()</v> @@ -438,14 +474,15 @@ release_handler:set_unpacked(RelFile, [{myapp,"1.0","/home/user"},...]). <desc> <p>Unpacks a release package <c>Name.tar.gz</c> located in the <c>releases</c> directory.</p> - <p>Performs some checks on the package - for example checks - that all mandatory files are present - and extracts its + <p>Performs some checks on the package, for example, checks + that all mandatory files are present, and extracts its contents.</p> </desc> </func> + <func> <name>which_releases() -> [{Name, Vsn, Apps, Status}]</name> - <fsummary>Return all known releases</fsummary> + <fsummary>Returns all known releases.</fsummary> <type> <v>Name = Vsn = string()</v> <v>Apps = ["App-Vsn"]</v> @@ -455,16 +492,18 @@ release_handler:set_unpacked(RelFile, [{myapp,"1.0","/home/user"},...]). <p>Returns all releases known to the release handler.</p> </desc> </func> + <func> <name>which_releases(Status) -> [{Name, Vsn, Apps, Status}]</name> - <fsummary>Return all known releases of a specific status</fsummary> + <fsummary>Returns all known releases of a specific status.</fsummary> <type> <v>Name = Vsn = string()</v> <v>Apps = ["App-Vsn"]</v> <v>Status = unpacked | current | permanent | old</v> </type> <desc> - <p>Returns all releases known to the release handler of a specific status.</p> + <p>Returns all releases, known to the release handler, of a + specific status.</p> </desc> </func> </funcs> @@ -473,7 +512,8 @@ release_handler:set_unpacked(RelFile, [{myapp,"1.0","/home/user"},...]). <title>Application Upgrade/Downgrade</title> <p>The following functions can be used to test upgrade and downgrade of single applications (instead of upgrading/downgrading an entire - release). A script corresponding to <c>relup</c> is created + release). A script corresponding to the instructions in the + <c>relup</c> file is created on-the-fly, based on the <c>.appup</c> file for the application, and evaluated exactly in the same way as <c>release_handler</c> does.</p> @@ -482,20 +522,22 @@ release_handler:set_unpacked(RelFile, [{myapp,"1.0","/home/user"},...]). of <c>.appup</c> files. They are not run within the context of the <c>release_handler</c> process. They must therefore <em>not</em> be used together with calls to - <c>install_release/1,2</c>, as this will cause + <seealso marker="#install_release/1"><c>install_release/1,2</c></seealso>, + as this causes the <c>release_handler</c> to end up in an inconsistent state.</p> - <p>No persistent information is updated, why these functions can + <p>No persistent information is updated, so these functions can be used on any Erlang node, embedded or not. Also, using these - functions does not affect which code will be loaded in case of + functions does not affect which code is loaded if there is a reboot.</p> - <p>If the upgrade or downgrade fails, the application may end up + <p>If the upgrade or downgrade fails, the application can end up in an inconsistent state.</p> </warning> </section> + <funcs> <func> <name>upgrade_app(App, Dir) -> {ok, Unpurged} | restart_emulator | {error, Reason}</name> - <fsummary>Upgrade to a new application version</fsummary> + <fsummary>Upgrades to a new application version.</fsummary> <type> <v>App = atom()</v> <v>Dir = string()</v> @@ -506,39 +548,46 @@ release_handler:set_unpacked(RelFile, [{myapp,"1.0","/home/user"},...]). <desc> <p>Upgrades an application <c>App</c> from the current version to a new version located in <c>Dir</c> according to - the <c>.appup</c> script.</p> + the <c>.appup</c> file.</p> <p><c>App</c> is the name of the application, which must be started. <c>Dir</c> is the new library directory of - <c>App</c>, the corresponding modules as well as - the <c>.app</c> and <c>.appup</c> files should be located + <c>App</c>. The corresponding modules as well as + the <c>.app</c> and <c>.appup</c> files are to be located under <c>Dir/ebin</c>.</p> <p>The function looks in the <c>.appup</c> file and tries to find an upgrade script from the current version of the application using - <seealso marker="#upgrade_script/2">upgrade_script/2</seealso>. + <seealso marker="#upgrade_script/2"><c>upgrade_script/2</c></seealso>. This script is evaluated using - <seealso marker="#eval_appup_script/4">eval_appup_script/4</seealso>, + <seealso marker="#eval_appup_script/4"><c>eval_appup_script/4</c></seealso>, exactly in the same way as - <seealso marker="#install_release/1">install_release/1,2</seealso> + <seealso marker="#install_release/1"><c>install_release/1,2</c></seealso> does.</p> - <p>Returns <c>{ok, Unpurged}</c> if evaluating the script is - successful, where <c>Unpurged</c> is a list of unpurged - modules, or <c>restart_emulator</c> if this instruction is - encountered in the script, or <c>{error, Reason}</c> if - an error occurred when finding or evaluating the script.</p> + <p>Returns one of the following:</p> + <list type="bulleted"> + <item><c>{ok, Unpurged}</c> if evaluating the script is + successful, where <c>Unpurged</c> is a list of unpurged + modules</item> + <item><c>restart_emulator</c> if this instruction is + encountered in the script</item> + <item><c>{error, Reason}</c> if an error occurred when + finding or evaluating the script</item> + </list> <p>If the <c>restart_new_emulator</c> instruction is found in - the script, <c>upgrade_app/2</c> will return - <c>{error,restart_new_emulator}</c>. The reason for this is - that this instruction requires that a new version of the - emulator is started before the rest of the upgrade - instructions can be executed, and this can only be done by - <c>install_release/1,2</c>.</p> + the script, + <seealso marker="#upgrade_app/2"><c>upgrade_app/2</c></seealso> + returns <c>{error,restart_new_emulator}</c>. This because + <c>restart_new_emulator</c> requires a new version of the + emulator to be started before the rest of the upgrade + instructions can be executed, and this can only be done by + <seealso marker="#install_release/1"><c>install_release/1,2</c></seealso>.</p> </desc> </func> + <func> <name>downgrade_app(App, Dir) -></name> <name>downgrade_app(App, OldVsn, Dir) -> {ok, Unpurged} | restart_emulator | {error, Reason}</name> - <fsummary>Downgrade to a previous application version</fsummary> + <fsummary>Downgrades to a previous application version.</fsummary> <type> <v>App = atom()</v> <v>Dir = OldVsn = string()</v> @@ -549,110 +598,124 @@ release_handler:set_unpacked(RelFile, [{myapp,"1.0","/home/user"},...]). <desc> <p>Downgrades an application <c>App</c> from the current version to a previous version <c>OldVsn</c> located in - <c>Dir</c> according to the <c>.appup</c> script.</p> + <c>Dir</c> according to the <c>.appup</c> file.</p> <p><c>App</c> is the name of the application, which must be - started. <c>OldVsn</c> is the previous version of - the application and can be omitted if <c>Dir</c> is of + started. <c>OldVsn</c> is the previous application version + and can be omitted if <c>Dir</c> is of the format <c>"App-OldVsn"</c>. <c>Dir</c> is the library - directory of this previous version of <c>App</c>, - the corresponding modules as well as the old <c>.app</c> file - should be located under <c>Dir/ebin</c>. The <c>.appup</c> - file should be located in the <c>ebin</c> directory of + directory of the previous version of <c>App</c>. + The corresponding modules and the old <c>.app</c> file + are to be located under <c>Dir/ebin</c>. The <c>.appup</c> + file is to be located in the <c>ebin</c> directory of the <em>current</em> library directory of the application - (<c>code:lib_dir(App)</c>).</p> + (<seealso marker="kernel:code#lib_dir/1"><c>code:lib_dir(App)</c></seealso>).</p> <p>The function looks in the <c>.appup</c> file and tries to - find an downgrade script to the previous version of + find a downgrade script to the previous version of the application using - <seealso marker="#downgrade_script/3">downgrade_script/3</seealso>. + <seealso marker="#downgrade_script/3"><c>downgrade_script/3</c></seealso>. This script is evaluated using - <seealso marker="#eval_appup_script/4">eval_appup_script/4</seealso>, + <seealso marker="#eval_appup_script/4"><c>eval_appup_script/4</c></seealso>, exactly in the same way as - <seealso marker="#install_release/1">install_release/1,2</seealso> + <seealso marker="#install_release/1"><c>install_release/1,2</c></seealso> does.</p> - <p>Returns <c>{ok, Unpurged}</c> if evaluating the script is - successful, where <c>Unpurged</c> is a list of unpurged - modules, or <c>restart_emulator</c> if this instruction is - encountered in the script, or <c>{error, Reason}</c> if - an error occurred when finding or evaluating the script.</p> + <p>Returns one of the following:</p> + <list type="bulleted"> + <item><c>{ok, Unpurged}</c> if evaluating the script is + successful, where <c>Unpurged</c> is a list of unpurged + modules</item> + <item><c>restart_emulator</c> if this instruction is + encountered in the script</item> + <item><c>{error, Reason}</c> if an error occurred when + finding or evaluating the script</item> + </list> </desc> </func> + <func> <name>upgrade_script(App, Dir) -> {ok, NewVsn, Script}</name> - <fsummary>Find an application upgrade script</fsummary> + <fsummary>Finds an application upgrade script.</fsummary> <type> <v>App = atom()</v> <v>Dir = string()</v> <v>NewVsn = string()</v> - <v>Script = Instructions -- see appup(4)</v> + <v>Script = Instructions</v> </type> <desc> <p>Tries to find an application upgrade script for <c>App</c> from the current version to a new version located in <c>Dir</c>.</p> <p>The upgrade script can then be evaluated using - <seealso marker="#eval_appup_script/4">eval_appup_script/4</seealso>. + <seealso marker="#eval_appup_script/4"><c>eval_appup_script/4</c></seealso>. It is recommended to use - <seealso marker="#upgrade_app/2">upgrade_app/2</seealso> - instead, but this function is useful in order to inspect - the contents of the script.</p> + <seealso marker="#upgrade_app/2"><c>upgrade_app/2</c></seealso> + instead, but this function (<c>upgrade_script</c>) is useful + to inspect the contents of the script.</p> <p><c>App</c> is the name of the application, which must be started. <c>Dir</c> is the new library directory of - <c>App</c>, the corresponding modules as well as - the <c>.app</c> and <c>.appup</c> files should be located + <c>App</c>. The corresponding modules as well as + the <c>.app</c> and <c>.appup</c> files are to be located under <c>Dir/ebin</c>.</p> <p>The function looks in the <c>.appup</c> file and tries to - find an upgrade script from the current version of - the application. High-level instructions are translated to - low-level instructions and the instructions are sorted in - the same manner as when generating a <c>relup</c> script.</p> + find an upgrade script from the current application version. + High-level instructions are translated to + low-level instructions. The instructions are sorted in + the same manner as when generating a <c>relup</c> file.</p> <p>Returns <c>{ok, NewVsn, Script}</c> if successful, where - <c>NewVsn</c> is the new application version.</p> + <c>NewVsn</c> is the new application version. + For details about <c>Script</c>, see + <seealso marker="appup"><c>appup(4)</c></seealso>.</p> <p>Failure: If a script cannot be found, the function fails with an appropriate error reason.</p> </desc> </func> + <func> <name>downgrade_script(App, OldVsn, Dir) -> {ok, Script}</name> - <fsummary>Find an application downgrade script</fsummary> + <fsummary>Finds an application downgrade script.</fsummary> <type> <v>App = atom()</v> <v>OldVsn = Dir = string()</v> - <v>Script = Instructions -- see appup(4)</v> + <v>Script = Instructions</v> </type> <desc> <p>Tries to find an application downgrade script for <c>App</c> from the current version to a previous version <c>OldVsn</c> located in <c>Dir</c>.</p> <p>The downgrade script can then be evaluated using - <seealso marker="#eval_appup_script/4">eval_appup_script/4</seealso>. + <seealso marker="#eval_appup_script/4"><c>eval_appup_script/4</c></seealso>. It is recommended to use - <seealso marker="#downgrade_app/2">downgrade_app/2,3</seealso> - instead, but this function is useful in order to inspect - the contents of the script.</p> + <seealso marker="#downgrade_app/2"><c>downgrade_app/2,3</c></seealso> + instead, but this function (<c>downgrade_script</c>) is useful + to inspect the contents of the script.</p> <p><c>App</c> is the name of the application, which must be started. <c>Dir</c> is the previous library directory of - <c>App</c>, the corresponding modules as well as - the old <c>.app</c> file should be located under - <c>Dir/ebin</c>. The <c>.appup</c> file should be located in + <c>App</c>. The corresponding modules and + the old <c>.app</c> file are to be located under + <c>Dir/ebin</c>. The <c>.appup</c> file is to be located in the <c>ebin</c> directory of the <em>current</em> library - directory of the application (<c>code:lib_dir(App)</c>).</p> + directory of the application + (<seealso marker="kernel:code#lib_dir/1"><c>code:lib_dir(App)</c>)</seealso>.</p> <p>The function looks in the <c>.appup</c> file and tries to - find an downgrade script from the current version of - the application. High-level instructions are translated to - low-level instructions and the instructions are sorted in - the same manner as when generating a <c>relup</c> script.</p> - <p>Returns <c>{ok, Script}</c> if successful.</p> + find a downgrade script from the current application version. + High-level instructions are translated to + low-level instructions. The instructions are sorted in + the same manner as when generating a <c>relup</c> file.</p> + <p>Returns <c>{ok, Script}</c> if successful. + For details about <c>Script</c>, see + <seealso marker="appup"><c>appup(4)</c></seealso>.</p> <p>Failure: If a script cannot be found, the function fails with an appropriate error reason.</p> </desc> </func> + <func> <name>eval_appup_script(App, ToVsn, ToDir, Script) -> {ok, Unpurged} | restart_emulator | {error, Reason}</name> - <fsummary>Evaluate an application upgrade or downgrade script</fsummary> + <fsummary>Evaluates an application upgrade or downgrade script.</fsummary> <type> <v>App = atom()</v> <v>ToVsn = ToDir = string()</v> - <v>Script -- see upgrade_script/2, downgrade_script/3</v> + <v>Script</v> + <d>See <seealso marker="#upgrade_script/2"><c>upgrade_script/2</c></seealso>, <seealso marker="#downgrade_script/3"><c>downgrade_script/3</c></seealso></d> <v>Unpurged = [Module]</v> <v> Module = atom()</v> <v>Reason = term()</v> @@ -660,114 +723,100 @@ release_handler:set_unpacked(RelFile, [{myapp,"1.0","/home/user"},...]). <desc> <p>Evaluates an application upgrade or downgrade script <c>Script</c>, the result from calling - <seealso marker="#upgrade_app/2">upgrade_script/2</seealso> or - <seealso marker="#downgrade_app/3">downgrade_script/3</seealso>, + <seealso marker="#upgrade_script/2"><c>upgrade_script/2</c></seealso> or + <seealso marker="#downgrade_script/3"><c>downgrade_script/3</c></seealso>, exactly in the same way as - <seealso marker="#install_release/1">install_release/1,2</seealso> + <seealso marker="#install_release/1"><c>install_release/1,2</c></seealso> does.</p> <p><c>App</c> is the name of the application, which must be started. <c>ToVsn</c> is the version to be upgraded/downgraded to, and <c>ToDir</c> is the library directory of this version. The corresponding modules as well as the <c>.app</c> and - <c>.appup</c> files should be located under <c>Dir/ebin</c>.</p> - <p>Returns <c>{ok, Unpurged}</c> if evaluating the script is - successful, where <c>Unpurged</c> is a list of unpurged - modules, or <c>restart_emulator</c> if this instruction is - encountered in the script, or <c>{error, Reason}</c> if - an error occurred when evaluating the script.</p> - <p>If the <c>restart_new_emulator</c> instruction is found in - the script, <c>eval_appup_script/4</c> will return - <c>{error,restart_new_emulator}</c>. The reason for this is - that this instruction requires that a new version of the - emulator is started before the rest of the upgrade - instructions can be executed, and this can only be done by - <c>install_release/1,2</c>.</p> + <c>.appup</c> files are to be located under <c>Dir/ebin</c>.</p> + <p>Returns one of the following:</p> + <list type="bulleted"> + <item><c>{ok, Unpurged}</c> if evaluating the script is + successful, where <c>Unpurged</c> is a list of unpurged + modules</item> + <item><c>restart_emulator</c> if this instruction is + encountered in the script</item> + <item><c>{error, Reason}</c> if an error occurred when + finding or evaluating the script</item> + </list> + <p>If the <c>restart_new_emulator</c> instruction is found in + the script, + <seealso marker="#eval_appup_script/4"><c>eval_appup_script/4</c></seealso> + returns <c>{error,restart_new_emulator}</c>. This because + <c>restart_new_emulator</c> requires a new version of the + emulator to be started before the rest of the upgrade + instructions can be executed, and this can only be done by + <seealso marker="#install_release/1"><c>install_release/1,2</c></seealso>.</p> </desc> </func> </funcs> <section> <title>Typical Error Reasons</title> - <list type="bulleted"> - <item> - <p><c>{bad_masters, Masters}</c> - The master nodes - <c>Masters</c> are not alive.</p> - </item> - <item> - <p><c>{bad_rel_file, File}</c> - Specified <c>.rel</c> file - <c>File</c> can not be read, or does not contain a single - term.</p> - </item> - <item> - <p><c>{bad_rel_data, Data}</c> - Specified <c>.rel</c> file - does not contain a recognized release specification, but - another term <c>Data</c>.</p> - </item> - <item> - <p><c>{bad_relup_file, File}</c> - Specified <c>relup</c> file - <c>Relup</c> contains bad data.</p> - </item> - <item> - <p><c>{cannot_extract_file, Name, Reason}</c> - Problems when - extracting from a tar file, <c>erl_tar:extract/2</c> returned - <c>{error, {Name, Reason}}</c>.</p> - </item> - <item> - <p><c>{existing_release, Vsn}</c> - Specified release version - <c>Vsn</c> is already in use.</p> - </item> - <item> - <p><c>{Master, Reason, When}</c> - Some operation, indicated by - the term <c>When</c>, failed on the master node <c>Master</c> - with the specified error reason <c>Reason</c>.</p> - </item> - <item> - <p><c>{no_matching_relup, Vsn, CurrentVsn}</c> - Cannot find a - script for up/downgrading between <c>CurrentVsn</c> and - <c>Vsn</c>.</p> - </item> - <item> - <p><c>{no_such_directory, Path}</c> - The directory <c>Path</c> - does not exist.</p> - </item> - <item> - <p><c>{no_such_file, Path}</c> - The path <c>Path</c> (file or - directory) does not exist.</p> - </item> - <item> - <p><c>{no_such_file, {Master, Path}}</c> - The path <c>Path</c> - (file or directory) does not exist at the master node - <c>Master</c>.</p> - </item> - <item> - <p><c>{no_such_release, Vsn}</c> - The specified version - <c>Vsn</c> of the release does not exist.</p> - </item> - <item> - <p><c>{not_a_directory, Path}</c> - <c>Path</c> exists, but is - not a directory.</p> - </item> - <item> - <p><c>{Posix, File}</c> - Some file operation failed for - <c>File</c>. <c>Posix</c> is an atom named from the Posix - error codes, such as <c>enoent</c>, <c>eacces</c> or - <c>eisdir</c>. See <c>file(3)</c>.</p> - </item> - <item> - <p><c>Posix</c> - Some file operation failed, as above.</p> - </item> - </list> + <taglist> + <tag><c>{bad_masters, Masters}</c></tag> + <item><p>The master nodes <c>Masters</c> are not alive.</p></item> + <tag><c>{bad_rel_file, File}</c></tag> + <item><p>Specified <c>.rel</c> file <c>File</c> cannot be read or + does not contain a single term.</p></item> + <tag><c>{bad_rel_data, Data}</c></tag> + <item><p>Specified <c>.rel</c> file does not contain a recognized + release specification, but another term <c>Data</c>.</p></item> + <tag><c>{bad_relup_file, File}</c></tag> + <item><p>Specified <c>relup</c> file <c>Relup</c> contains bad + data.</p></item> + <tag><c>{cannot_extract_file, Name, Reason}</c></tag> + <item><p>Problems when extracting from a tar file, + <seealso marker="stdlib:erl_tar#extract/2"><c>erl_tar:extract/2</c></seealso> + returned <c>{error, {Name, Reason}}</c>.</p></item> + <tag><c>{existing_release, Vsn}</c></tag> + <item><p>Specified release version <c>Vsn</c> is already + in use.</p></item> + <tag><c>{Master, Reason, When}</c></tag> + <item><p>Some operation, indicated by the term <c>When</c>, failed + on the master node <c>Master</c> with the specified error + reason <c>Reason</c>.</p></item> + <tag><c>{no_matching_relup, Vsn, CurrentVsn}</c></tag> + <item><p>Cannot find a script for upgrading/downgrading between + <c>CurrentVsn</c> and <c>Vsn</c>.</p></item> + <tag><c>{no_such_directory, Path}</c></tag> + <item><p>The directory <c>Path</c>does not exist.</p></item> + <tag><c>{no_such_file, Path}</c></tag> + <item><p>The path <c>Path</c> (file or directory) does not + exist.</p></item> + <tag><c>{no_such_file, {Master, Path}}</c></tag> + <item><p>The path <c>Path</c> (file or directory) does not exist at + the master node <c>Master</c>.</p></item> + <tag><c>{no_such_release, Vsn}</c></tag> + <item><p>The specified release version <c>Vsn</c> does not + exist.</p></item> + <tag><c>{not_a_directory, Path}</c></tag> + <item><p><c>Path</c> exists but is not a directory.</p></item> + <tag><c>{Posix, File}</c></tag> + <item><p>Some file operation failed for <c>File</c>. <c>Posix</c> + is an atom named from the Posix error codes, such as + <c>enoent</c>, <c>eacces</c>, or <c>eisdir</c>. See + <seealso marker="kernel:file"><c>file(3)</c></seealso> + in <c>Kernel</c>.</p></item> + <tag><c>Posix</c></tag> + <item><p>Some file operation failed, as for the previous item in + the list.</p></item> + </taglist> </section> <section> - <title>SEE ALSO</title> - <p><seealso marker="doc/design_principles:release_handling">OTP Design Principles</seealso>, - <seealso marker="kernel:config">config(4)</seealso>, - <seealso marker="relup">relup(4)</seealso>, - <seealso marker="rel">rel(4)</seealso>, - <seealso marker="script">script(4)</seealso>, - <seealso marker="stdlib:sys">sys(3)</seealso>, - <seealso marker="systools">systools(3)</seealso></p> + <title>See Also</title> + <p><seealso marker="doc/design_principles:users_guide">OTP Design Principles</seealso>, + <seealso marker="kernel:config"><c>config(4)</c></seealso>, + <seealso marker="rel"><c>rel(4)</c></seealso>, + <seealso marker="relup"><c>relup(4)</c></seealso>, + <seealso marker="script"><c>script(4)</c></seealso>, + <seealso marker="stdlib:sys"><c>sys(3)</c></seealso>, + <seealso marker="systools"><c>systools(3)</c></seealso></p> </section> </erlref> |