From 12e625436c53b806ec66552251483755583b0c07 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Lo=C3=AFc=20Hoguin?= Date: Mon, 28 Aug 2017 16:35:31 +0200 Subject: Document CI and OTP version management/pinning --- doc/src/guide/kerl.asciidoc | 76 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 76 insertions(+) create mode 100644 doc/src/guide/kerl.asciidoc (limited to 'doc/src/guide/kerl.asciidoc') diff --git a/doc/src/guide/kerl.asciidoc b/doc/src/guide/kerl.asciidoc new file mode 100644 index 0000000..c557d43 --- /dev/null +++ b/doc/src/guide/kerl.asciidoc @@ -0,0 +1,76 @@ +[[kerl]] +== OTP version management + +Erlang.mk comes with integrated support for +https://github.com/kerl/kerl[Kerl], a shell script that +automates the downloading, building and installing of +Erlang/OTP. It can be used to easily build a specific +Erlang/OTP version (with or without custom build options) +or maintain different versions side by side. + +=== Erlang versions + +Erlang.mk uses the Git tags from Erlang/OTP to identify +OTP versions. The most recent tag at the time of writing +is `OTP-20.0.4`, which is a patch release of `OTP-20.0`. +A patch release is a non-official release containing a +few fixes on top of the official release. + +Older versions used a slightly different versioning scheme +and tag format, for example: `OTP_R16B03`. Beware though, +there also was an `OTP_R16B03-1` release that fixed a +critical issue in the initial release. + +The README file for all official Erlang/OTP releases can +be found on http://www.erlang.org/downloads[erlang.org]. +To obtain information about patch releases when they are +released you need to be subscribed to the +http://erlang.org/mailman/listinfo/erlang-questions[erlang-questions mailing list]. + +[[otp_version_pinning]] +=== OTP version pinning + +Erlang.mk can use a specific version of Erlang/OTP when +interacting with your project. This can be very useful +when you are working with a team because you can define +the version you need in the Makefile and Erlang.mk will +ensure this version is used by everyone in your team. + +To pin the version all you need to do is to set the +`ERLANG_OTP` variable in your Makefile before including +Erlang.mk. For example, to use `OTP-20.0.4`: + +[source,make] +---- +ERLANG_OTP = OTP-20.0.4 + +include erlang.mk +---- + +The next time you run `make` Erlang.mk will build and +use the version you configured. + +Note that there has been reports that this functionality +is not compatible with the `.ONESHELL` feature from +GNU Make. + +=== Continuous integration + +Erlang.mk can automatically test your project against +many different Erlang/OTP versions. This functionality +is documented in the xref:ci[Continuous integration] chapter. + +=== Configuring Kerl + +All of the Kerl variables can be configured directly in the +Makefile. All you need to do is to export them. For example, +to change the installation directory for the Erlang/OTP +versions managed by Kerl, you could add the following to +your Makefile: + +[source,make] +export KERL_INSTALL_DIR = $(CURDIR)/erlang + +When configuring paths like this, always make sure to provide +an absolute path in the value. Erlang.mk will NOT expand them +automatically for you. -- cgit v1.2.3