Add support to define macros as environment variables

Define and macro by setting as environment variable:
  EJABBERD_MACRO_ + macro name

For example, if you configure in ejabberd.yml:
  define_macro:
    LOGLEVEL: 4
  loglevel: LOGLEVEL

You can define (and overwrite) that macro definition when starting ejabberd:
  EJABBERD_MACRO_LOGLEVEL=5 make relive

CONTAINER.md

@@ -234,6 +234,30 @@ Example usage (or check the [full example](#customized-example)):
 ```
 
 
+### Macros in environment
+
+ejabberd reads `EJABBERD_MACRO_*` environment variables
+and uses them to define the `*`
+[macros](https://docs.ejabberd.im/admin/configuration/file-format/#macros-in-configuration-file),
+overwriting the corresponding macro definition if it was set in the configuration file.
+
+For example, if you configure this in `ejabberd.yml`:
+
+```yaml
+acl:
+  admin:
+    user: ADMINJID
+```
+
+now you can define the admin account JID using an environment variable:
+```yaml
+    environment:
+      - EJABBERD_MACRO_ADMINJID=admin@localhost
+```
+
+Check the [full example](#customized-example) for other example.
+
+
 ### Clustering
 
 When setting several containers to form a
@@ -371,6 +395,7 @@ docker-compose up
 
 This example shows the usage of several customizations:
 it uses a local configuration file,
+defines a configuration macro using an environment variable,
 stores the mnesia database in a local path,
 registers an account when it's created,
 and checks the number of registered accounts every time it's started.
@@ -381,6 +406,14 @@ wget https://raw.githubusercontent.com/processone/ejabberd/master/ejabberd.yml.e
 mv ejabberd.yml.example ejabberd.yml
 ```
 
+Use a macro in `ejabberd.yml` to set the served vhost, with `localhost` as default value:
+```bash
+define_macro:
+  XMPPHOST: localhost
+hosts:
+  - XMPPHOST
+```
+
 Create the database directory and allow the container access to it:
 ```bash
 mkdir database
@@ -397,8 +430,9 @@ services:
     image: ghcr.io/processone/ejabberd
     container_name: ejabberd
     environment:
-      - CTL_ON_CREATE=register admin localhost asd
+      - EJABBERD_MACRO_XMPPHOST=example.com
-      - CTL_ON_START=registered_users localhost ;
+      - CTL_ON_CREATE=register admin example.com asd
+      - CTL_ON_START=registered_users example.com ;
                      status
     ports:
       - "5222:5222"

mix.exs

@@ -145,7 +145,7 @@ defmodule Ejabberd.MixProject do
      {:pkix, "~> 1.0"},
      {:stringprep, ">= 1.0.26"},
      {:xmpp, "~> 1.9"},
-     {:yconf, "~> 1.0"}]
+     {:yconf, git: "https://github.com/processone/yconf.git", ref: "9898754f16cbd4585a1c2061d72fa441ecb2e938", override: true}]
     ++ cond_deps()
   end
 

mix.lock

@@ -35,5 +35,5 @@
   "stun": {:hex, :stun, "1.2.15", "eec510af6509201ff97f1f2c87b7977c833bf29c04e985383370ec21f04e4ccf", [:rebar3], [{:fast_tls, "1.1.22", [hex: :fast_tls, repo: "hexpm", optional: false]}, {:p1_utils, "1.0.26", [hex: :p1_utils, repo: "hexpm", optional: false]}], "hexpm", "f6d8a541a29fd13f2ce658b676c0cc661262b96e045b52def1644b75ebc0edef"},
   "unicode_util_compat": {:hex, :unicode_util_compat, "0.7.0", "bc84380c9ab48177092f43ac89e4dfa2c6d62b40b8bd132b1059ecc7232f9a78", [:rebar3], [], "hexpm", "25eee6d67df61960cf6a794239566599b09e17e668d3700247bc498638152521"},
   "xmpp": {:hex, :xmpp, "1.9.0", "d92446bf51d36adda02db63b963fe6d4a1ede33e59b38a43d9b90afd20c25b74", [:rebar3], [{:ezlib, "~> 1.0.12", [hex: :ezlib, repo: "hexpm", optional: false]}, {:fast_tls, "~> 1.1.19", [hex: :fast_tls, repo: "hexpm", optional: false]}, {:fast_xml, "~> 1.1.51", [hex: :fast_xml, repo: "hexpm", optional: false]}, {:idna, "~> 6.0", [hex: :idna, repo: "hexpm", optional: false]}, {:p1_utils, "~> 1.0.25", [hex: :p1_utils, repo: "hexpm", optional: false]}, {:stringprep, "~> 1.0.29", [hex: :stringprep, repo: "hexpm", optional: false]}], "hexpm", "c1b91be74a9a9503afa6766f756477516920ffbfeea0c260c2fa171355f53c27"},
-  "yconf": {:hex, :yconf, "1.0.16", "d59521d66ff89f219411b6e9277cd6feec7cc6fce11554e67de02a8d0a470479", [:rebar3], [{:fast_yaml, "1.0.37", [hex: :fast_yaml, repo: "hexpm", optional: false]}], "hexpm", "e947813273f38711c7b2e5a8e4acc9a51c7bbe854f744a345f60300b38586c89"},
+  "yconf": {:git, "https://github.com/processone/yconf.git", "9898754f16cbd4585a1c2061d72fa441ecb2e938", [ref: "9898754f16cbd4585a1c2061d72fa441ecb2e938"]},
 }

rebar.config

@@ -70,7 +70,7 @@
         {if_var_true, stun,
          {stun, "~> 1.2.12", {git, "https://github.com/processone/stun", {tag, "1.2.15"}}}},
         {xmpp, "~> 1.9.0", {git, "https://github.com/processone/xmpp", {tag, "1.9.0"}}},
-        {yconf, "~> 1.0.15", {git, "https://github.com/processone/yconf", {tag, "1.0.16"}}}
+        {yconf, ".*", {git, "https://github.com/processone/yconf", "9898754f16cbd4585a1c2061d72fa441ecb2e938"}}
        ]}.
 
 {gitonly_deps, [ejabberd_po]}.

rebar.lock

@@ -25,7 +25,10 @@
  {<<"stun">>,{pkg,<<"stun">>,<<"1.2.15">>},0},
  {<<"unicode_util_compat">>,{pkg,<<"unicode_util_compat">>,<<"0.7.0">>},1},
  {<<"xmpp">>,{pkg,<<"xmpp">>,<<"1.9.0">>},0},
- {<<"yconf">>,{pkg,<<"yconf">>,<<"1.0.16">>},0}]}.
+ {<<"yconf">>,
+  {git,"https://github.com/processone/yconf",
+       {ref,"9898754f16cbd4585a1c2061d72fa441ecb2e938"}},
+  0}]}.
 [
 {pkg_hash,[
  {<<"base64url">>, <<"F8C7F2DA04CA9A5D0F5F50258F055E1D699F0E8BF4CFDB30B750865368403CF6">>},
@@ -53,8 +56,7 @@
  {<<"stringprep">>, <<"46CF0FF631B3E7328F61F20B454D59428D87738F25D709798B5DCBB9B83C23F1">>},
  {<<"stun">>, <<"EEC510AF6509201FF97F1F2C87B7977C833BF29C04E985383370EC21F04E4CCF">>},
  {<<"unicode_util_compat">>, <<"BC84380C9AB48177092F43AC89E4DFA2C6D62B40B8BD132B1059ECC7232F9A78">>},
- {<<"xmpp">>, <<"D92446BF51D36ADDA02DB63B963FE6D4A1EDE33E59B38A43D9B90AFD20C25B74">>},
+ {<<"xmpp">>, <<"D92446BF51D36ADDA02DB63B963FE6D4A1EDE33E59B38A43D9B90AFD20C25B74">>}]},
- {<<"yconf">>, <<"D59521D66FF89F219411B6E9277CD6FEEC7CC6FCE11554E67DE02A8D0A470479">>}]},
 {pkg_hash_ext,[
  {<<"base64url">>, <<"F9B3ADD4731A02A9B0410398B475B33E7566A695365237A6BDEE1BB447719F5C">>},
  {<<"cache_tab">>, <<"8582B60A4A09B247EF86355BA9E07FCE9E11EDC0345A775C9171F971C72B6351">>},
@@ -81,6 +83,5 @@
  {<<"stringprep">>, <<"F6FC9B3384A03877830F89B2F38580CAF3F4A27448A4A333D6A8C3975C220B9A">>},
  {<<"stun">>, <<"F6D8A541A29FD13F2CE658B676C0CC661262B96E045B52DEF1644B75EBC0EDEF">>},
  {<<"unicode_util_compat">>, <<"25EEE6D67DF61960CF6A794239566599B09E17E668D3700247BC498638152521">>},
- {<<"xmpp">>, <<"C1B91BE74A9A9503AFA6766F756477516920FFBFEEA0C260C2FA171355F53C27">>},
+ {<<"xmpp">>, <<"C1B91BE74A9A9503AFA6766F756477516920FFBFEEA0C260C2FA171355F53C27">>}]}
- {<<"yconf">>, <<"E947813273F38711C7B2E5A8E4ACC9A51C7BBE854F744A345F60300B38586C89">>}]}
 ].

src/ejabberd_config.erl

@@ -516,8 +516,23 @@ read_file(File, Opts) ->
 	    Err
     end.
 
+get_additional_macros() ->
+    MacroStrings = lists:foldl(fun([$E, $J, $A, $B, $B, $E, $R, $D, $_, $M, $A, $C, $R, $O, $_ | MacroString], Acc) ->
+                                        [parse_macro_string(MacroString) | Acc];
+                                   (_, Acc) ->
+                                        Acc
+                                end,
+                                [],
+                                os:getenv()),
+    {additional_macros, MacroStrings}.
+
+parse_macro_string(MacroString) ->
+    [NameString, ValueString] = string:split(MacroString, "="),
+    {ok, [ValueDecoded]} = fast_yaml:decode(ValueString, [plain_as_atom]),
+    {list_to_atom(NameString), ValueDecoded}.
+
 read_yaml_files(Files, Opts) ->
-    ParseOpts = [plain_as_atom | lists:flatten(Opts)],
+    ParseOpts = [plain_as_atom, get_additional_macros() | lists:flatten(Opts)],
     lists:foldl(
       fun(File, {ok, Y1}) ->
 	      case econf:parse(File, #{'_' => econf:any()}, ParseOpts) of