[snmp/agent] enable SNMP to create missing database directories

Add {db_init_error, create_db_and_dir} option to SNMP manager and
agent. This allows them to create any missing parent directories for
db_dir, rather than treating any missing directories as a fatal error.

The default for db_init_error, which is terminate, is unchanged.

Add create_db_and_dir to the documentation.

Add new tests to verify that using create_db_and_dir results in missing
parent directories being created.

2 files changed, 109 insertions, 4 deletions

diff --git a/lib/snmp/test/snmp_agent_test.erl b/lib/snmp/test/snmp_agent_test.erl
index 7e683e315a..b7d34eb198 100644
--- a/lib/snmp/test/snmp_agent_test.erl
+++ b/lib/snmp/test/snmp_agent_test.erl
@@ -34,6 +34,7 @@
 	 %% all_tcs - misc
 	 app_info/1, 
 	 info_test/1, 
+         create_local_db_dir/1,
 
 	 %% all_tcs - test_v1
 	 simple/1, 
@@ -1506,7 +1507,8 @@ finish_misc(Config) ->
 misc_cases() -> 
     [
      app_info, 
-     info_test
+     info_test,
+     create_local_db_dir
     ].
 
 app_info(suite) -> [];
@@ -1539,7 +1541,75 @@ app_dir(App) ->
 	    "undefined"
     end.
 
+create_local_db_dir(Config) when is_list(Config) ->
+    ?P(create_local_db_dir),
+    DataDir = snmp_test_lib:lookup(data_dir, Config),
+    T = erlang:now(),
+    [As,Bs,Cs] = [integer_to_list(I) || I <- tuple_to_list(T)],
+    DbDir = filename:join([DataDir, As, Bs, Cs]),
+    ok = del_dir(DbDir, 3),
+    Name = list_to_atom(atom_to_list(create_local_db_dir)
+                        ++"-"++As++"-"++Bs++"-"++Cs),
+    Pa = filename:dirname(code:which(?MODULE)),
+    {ok,Node} = ?t:start_node(Name, slave, [{args, "-pa "++Pa}]),
+
+    %% first start with a nonexisting DbDir
+    Fun1 = fun() ->
+                   false = filelib:is_dir(DbDir),
+                   process_flag(trap_exit,true),
+                   {error, {error, {failed_open_dets, {file_error, _, _}}}} =
+                       snmpa_local_db:start_link(normal, DbDir, [{verbosity,trace}]),
+                   false = filelib:is_dir(DbDir),
+                   {ok, not_found}
+           end,
+    {ok, not_found} = nodecall(Node, Fun1),
+    %% now start with a nonexisting DbDir but pass the
+    %% create_local_db_dir option as well
+    Fun2 = fun() ->
+                   false = filelib:is_dir(DbDir),
+                   process_flag(trap_exit,true),
+                   {ok, _Pid} =
+                       snmpa_local_db:start_link(normal, DbDir,
+                                                 create_db_and_dir, [{verbosity,trace}]),
+                   snmpa_local_db:stop(),
+                   true = filelib:is_dir(DbDir),
+                   {ok, found}
+           end,
+    {ok, found} = nodecall(Node, Fun2),
+    %% cleanup
+    ?t:stop_node(Node),
+    ok = del_dir(DbDir, 3),
+    ok.
+
+nodecall(Node, Fun) ->
+    Parent = self(),
+    Ref = make_ref(),
+    spawn_link(Node,
+               fun() ->
+                       Res = Fun(),
+                       unlink(Parent),
+                       Parent ! {Ref, Res}
+               end),
+    receive
+        {Ref, Res} ->
+            Res
+    end.
 
+del_dir(_Dir, 0) ->
+    ok;
+del_dir(Dir, Depth) ->
+    case filelib:is_dir(Dir) of
+        true ->
+            {ok, Files} = file:list_dir(Dir),
+            lists:map(fun(F) ->
+                              Nm = filename:join(Dir,F),
+                              ok = file:delete(Nm)
+                      end, Files),
+            ok = file:del_dir(Dir),
+            del_dir(filename:dirname(Dir), Depth-1);
+        false ->
+            ok
+    end.
 
 %v1_cases() -> [loop_mib];
 v1_cases() -> 
diff --git a/lib/snmp/test/snmp_manager_config_test.erl b/lib/snmp/test/snmp_manager_config_test.erl
index 3192fe1b40..a2733cd043 100644
--- a/lib/snmp/test/snmp_manager_config_test.erl
+++ b/lib/snmp/test/snmp_manager_config_test.erl
@@ -57,6 +57,7 @@
 	 start_with_invalid_users_conf_file1/1,
 	 start_with_invalid_agents_conf_file1/1,
 	 start_with_invalid_usm_conf_file1/1,
+         start_with_create_db_and_dir_opt/1,
 
 	
 
@@ -139,8 +140,13 @@ init_per_testcase(Case, Config) when is_list(Config) ->
 	file:make_dir(MgrTopDir  = filename:join(CaseTopDir, "manager/")),
     ?line ok = 
 	file:make_dir(MgrConfDir = filename:join(MgrTopDir,   "conf/")),
-    ?line ok = 
-	file:make_dir(MgrDbDir   = filename:join(MgrTopDir,   "db/")),
+    MgrDbDir = filename:join(MgrTopDir, "db/"),
+    case Case of
+	start_with_create_db_and_dir_opt ->
+	    ok;
+	_ ->
+	    ?line ok = file:make_dir(MgrDbDir)
+    end,
     ?line ok = 
 	file:make_dir(MgrLogDir  = filename:join(MgrTopDir,   "log/")),
     [{case_top_dir,     CaseTopDir},
@@ -174,6 +180,7 @@ groups() ->
        start_without_mandatory_opts2,
        start_with_all_valid_opts, start_with_unknown_opts,
        start_with_incorrect_opts,
+       start_with_create_db_and_dir_opt,
        start_with_invalid_manager_conf_file1,
        start_with_invalid_users_conf_file1,
        start_with_invalid_agents_conf_file1,
@@ -332,7 +339,8 @@ start_with_all_valid_opts(Conf) when is_list(Conf) ->
 			       {no_reuse, false}]}],
     ServerOpts = [{timeout, 10000}, {verbosity, trace}],
     NoteStoreOpts = [{timeout, 20000}, {verbosity, trace}],
-    ConfigOpts = [{dir, ConfDir}, {verbosity, trace}, {db_dir, DbDir}],
+    ConfigOpts = [{dir, ConfDir}, {verbosity, trace},
+                  {db_dir, DbDir}, {db_init_error, create}],
     Mibs = [join(StdMibDir, "SNMP-NOTIFICATION-MIB"),
 	    join(StdMibDir, "SNMP-USER-BASED-SM-MIB")],
     Prio = normal,
@@ -1674,7 +1682,34 @@ start_with_invalid_usm_conf_file1(Conf) when is_list(Conf) ->
 %% ---
 %% 
 
+start_with_create_db_and_dir_opt(suite) -> [];
+start_with_create_db_and_dir_opt(doc) ->
+    "Start the snmp manager config process with the\n"
+        "create_db_and_dir option.";
+start_with_create_db_and_dir_opt(Conf) when is_list(Conf) ->
+    put(tname, swcdado),
+    p("start"),
+    process_flag(trap_exit, true),
+    ConfDir = ?config(manager_conf_dir, Conf),
+    DbDir = ?config(manager_db_dir, Conf),
+    true = not filelib:is_dir(DbDir) and not filelib:is_file(DbDir),
+    write_manager_conf(ConfDir),
+
+    p("verify nonexistent db_dir"),
+    ConfigOpts01 = [{verbosity,trace}, {dir, ConfDir}, {db_dir, DbDir}],
+    {error, Reason01} = config_start([{config, ConfigOpts01}]),
+    p("nonexistent db_dir res: ~p", [Reason01]),
+    {invalid_conf_db_dir, _, not_found} = Reason01,
 
+    p("verify nonexistent db_dir gets created"),
+    ConfigOpts02 = [{db_init_error, create_db_and_dir} | ConfigOpts01],
+    {ok, _Pid} = config_start([{config, ConfigOpts02}]),
+    true = filelib:is_dir(DbDir),
+    p("verified: nonexistent db_dir was correctly created"),
+    ok = config_stop(),
+
+    p("done"),
+    ok.
 
 %% 
 %% ---