Merge pull request 2600hz#1712 from 2600hz/KAZOO-4613

KAZOO-4613: read a release`s cookie from conf, for services or SUP co…

Makefile

@@ -4,7 +4,7 @@ ELVIS = $(ROOT)/utils/elvis/elvis
 
 KAZOODIRS = core/Makefile applications/Makefile
 
-.PHONY: $(KAZOODIRS) deps core apps xref xref_release dialyze dialyze-apps dialyze-core dialyze-kazoo clean clean-test clean-release build-release tar-release release elvis
+.PHONY: $(KAZOODIRS) deps core apps xref xref_release dialyze dialyze-apps dialyze-core dialyze-kazoo clean clean-test clean-release build-release tar-release release read-release-cookie elvis
 
 all: compile rel/dev-vm.args
 
@@ -91,6 +91,10 @@ endif
 	@RELX_REPLACE_OS_VARS=true KZname='-name $(REL)' _rel/kazoo/bin/kazoo $(ACT) "$$@"
 
 
+read-release-cookie: REL ?= whistle_apps
+read-release-cookie:
+	@RELX_REPLACE_OS_VARS=true KZname='-name $(REL)' _rel/kazoo/bin/kazoo escript lib/whistle_config-*/priv/read-cookie.escript "$$@"
+
 DIALYZER ?= dialyzer
 PLT ?= .kazoo.plt
 OTP_APPS ?= erts kernel stdlib crypto public_key ssl asn1 inets

core/whistle_config/priv/read-cookie.escript

@@ -0,0 +1,21 @@
+#!/usr/bin/env escript
+%%!
+%% -*- coding: utf-8 -*-
+
+%% Reads a running release's cookie from config.ini
+
+-mode('compile').
+
+-export([main/1]).
+
+%% API
+
+main(_) ->
+    "-name "++Release = os:getenv("KZname"),
+    REL = list_to_atom(Release),
+    INI = whistle_config_init:load_file(),
+    {_, RelEnv} = lists:keyfind(REL, 1, INI),
+    {_, Cookie} = lists:keyfind('cookie', 1, RelEnv),
+    io:format("~s\n", [Cookie]).
+
+%% End of Module

core/whistle_config/src/whistle_config_init.erl

@@ -13,13 +13,16 @@
          ,reload/0
         ]).
 
+%% To read config.ini
+-export([load_file/0]).
+
 %%--------------------------------------------------------------------
 %% @public
 %% @doc Starts the app for inclusion in a supervisor tree
 %%--------------------------------------------------------------------
 -spec start_link() -> startlink_ret().
 start_link() ->
-	set_env(),
+    set_env(),
     'ignore'.
 
 ini_file() ->
@@ -28,28 +31,31 @@ ini_file() ->
         File -> File
     end.
 
--spec load_file(string()) -> {'ok', wh_proplist()}.
+-spec load_file() -> wh_proplist().
+-spec load_file(file:name()) -> wh_proplist().
+load_file() ->
+    load_file(ini_file()).
 load_file(File) ->
     case zucchini:parse_file(File) of
         {'ok', Prop} ->
             lager:info("loaded configs from file ~s", [File]),
-            {'ok', Prop};
+            Prop;
         {'error', 'enoent'} ->
             lager:warning("file ~s does not exist or is not accessible", [File]),
             lager:warning("please create ~s or set the environment variable ~s to the path of the config file", [File, ?CONFIG_FILE_ENV]),
             lager:warning("trying defaults instead"),
-            {'ok', ?SECTION_DEFAULTS};
+            ?SECTION_DEFAULTS;
         {'error', _}=Error ->
             lager:warning("error loading file ~s: ~s", [File, Error]),
             lager:warning("trying defaults instead"),
-            {'ok', ?SECTION_DEFAULTS}
+            ?SECTION_DEFAULTS
     end.
 
 -spec set_env() -> 'ok'.
 set_env() ->
-    {'ok', X} = load_file(ini_file()),
-    lager:debug("setting config env ~p", [X]),
-    application:set_env('whistle_config', 'wh_config', X).
+    AppEnv = load_file(),
+    lager:debug("setting config env ~p", [AppEnv]),
+    application:set_env('whistle_config', 'wh_config', AppEnv).
 
 -spec reload() -> 'ok'.
 reload() ->

doc/engineering/releases.md

@@ -81,3 +81,13 @@ When troubleshooting, this attaches a REPL to the running faulty `ecallmgr` node
 This gracefully stops an `ecallmgr` node:
 
     REL=ecallmgr ACT=stop   make release
+
+
+### Read a release's cookie from Kazoo's configuration
+
+    REL=whistle_apps make read-release-cookie
+
+This hits `/etc/kazoo/config.ini` or the file at `$KAZOO_CONFIG`
+and reads the cookie value for release `REL`.
+
+Note: the release does not even need to be started!