From e808fef1e47d6ae9f2aae7cc8d039d6c5fa4003d Mon Sep 17 00:00:00 2001
From: Kjell Winblad <kjellwinblad@gmail.com>
Date: Thu, 30 Mar 2023 17:49:56 +0200
Subject: [PATCH 1/2] feat: (MongoDB bridge) use ${var} syntax for MongoDB
 collection

This commit makes it possible to use the ${var} syntax to refer to
variables in the payload of the message in the collection field.
This makes it possible to select which collection to insert into
dynamically.

Fixes:
https://emqx.atlassian.net/browse/EMQX-9246
---
 .../test/emqx_ee_bridge_mongodb_SUITE.erl     | 24 ++++++++++++++++++-
 .../src/emqx_ee_connector_mongodb.erl         |  9 ++++++-
 2 files changed, 31 insertions(+), 2 deletions(-)

diff --git a/lib-ee/emqx_ee_bridge/test/emqx_ee_bridge_mongodb_SUITE.erl b/lib-ee/emqx_ee_bridge/test/emqx_ee_bridge_mongodb_SUITE.erl
index f81571223..9850c9529 100644
--- a/lib-ee/emqx_ee_bridge/test/emqx_ee_bridge_mongodb_SUITE.erl
+++ b/lib-ee/emqx_ee_bridge/test/emqx_ee_bridge_mongodb_SUITE.erl
@@ -26,7 +26,8 @@ group_tests() ->
     [
         t_setup_via_config_and_publish,
         t_setup_via_http_api_and_publish,
-        t_payload_template
+        t_payload_template,
+        t_collection_template
     ].
 
 groups() ->
@@ -302,3 +303,24 @@ t_payload_template(Config) ->
         find_all(Config)
     ),
     ok.
+
+t_collection_template(Config) ->
+    {ok, _} = create_bridge(
+        Config,
+        #{
+            <<"payload_template">> => <<"{\"foo\": \"${clientid}\"}">>,
+            <<"collection">> => <<"${mycollectionvar}">>
+        }
+    ),
+    Val = erlang:unique_integer(),
+    ClientId = emqx_guid:to_hexstr(emqx_guid:gen()),
+    ok = send_message(Config, #{
+        key => Val,
+        clientid => ClientId,
+        mycollectionvar => <<"mycol">>
+    }),
+    ?assertMatch(
+        {ok, [#{<<"foo">> := ClientId}]},
+        find_all(Config)
+    ),
+    ok.
diff --git a/lib-ee/emqx_ee_connector/src/emqx_ee_connector_mongodb.erl b/lib-ee/emqx_ee_connector/src/emqx_ee_connector_mongodb.erl
index b1327fef6..8df77fbe0 100644
--- a/lib-ee/emqx_ee_connector/src/emqx_ee_connector_mongodb.erl
+++ b/lib-ee/emqx_ee_connector/src/emqx_ee_connector_mongodb.erl
@@ -35,8 +35,11 @@ on_start(InstanceId, Config) ->
         {ok, ConnectorState} ->
             PayloadTemplate0 = maps:get(payload_template, Config, undefined),
             PayloadTemplate = preprocess_template(PayloadTemplate0),
+            CollectionTemplateSource = maps:get(collection, Config),
+            CollectionTemplate = preprocess_template(CollectionTemplateSource),
             State = #{
                 payload_template => PayloadTemplate,
+                collection_template => CollectionTemplate,
                 connector_state => ConnectorState
             },
             {ok, State};
@@ -50,10 +53,14 @@ on_stop(InstanceId, _State = #{connector_state := ConnectorState}) ->
 on_query(InstanceId, {send_message, Message0}, State) ->
     #{
         payload_template := PayloadTemplate,
+        collection_template := CollectionTemplate,
         connector_state := ConnectorState
     } = State,
+    NewConnectorState = ConnectorState#{
+        collection => emqx_plugin_libs_rule:proc_tmpl(CollectionTemplate, Message0)
+    },
     Message = render_message(PayloadTemplate, Message0),
-    emqx_connector_mongo:on_query(InstanceId, {send_message, Message}, ConnectorState);
+    emqx_connector_mongo:on_query(InstanceId, {send_message, Message}, NewConnectorState);
 on_query(InstanceId, Request, _State = #{connector_state := ConnectorState}) ->
     emqx_connector_mongo:on_query(InstanceId, Request, ConnectorState).
 

From 91df54028786d5ed0b9c0cc3bcba1b883f077aae Mon Sep 17 00:00:00 2001
From: Kjell Winblad <kjellwinblad@gmail.com>
Date: Fri, 31 Mar 2023 06:36:21 +0200
Subject: [PATCH 2/2] docs: add changelog entry for MongoDB ${var} syntax for
 collection

---
 changes/ee/feat-10294.en.md | 1 +
 changes/ee/feat-10294.zh.md | 1 +
 2 files changed, 2 insertions(+)
 create mode 100644 changes/ee/feat-10294.en.md
 create mode 100644 changes/ee/feat-10294.zh.md

diff --git a/changes/ee/feat-10294.en.md b/changes/ee/feat-10294.en.md
new file mode 100644
index 000000000..cac3a7587
--- /dev/null
+++ b/changes/ee/feat-10294.en.md
@@ -0,0 +1 @@
+When configuring a MongoDB bridge, you can now use the ${var} syntax to reference fields in the message payload within the collection field. This enables you to select the collection to insert data into dynamically.
diff --git a/changes/ee/feat-10294.zh.md b/changes/ee/feat-10294.zh.md
new file mode 100644
index 000000000..ca1727012
--- /dev/null
+++ b/changes/ee/feat-10294.zh.md
@@ -0,0 +1 @@
+在配置 MongoDB 桥时，现在可以使用 ${var} 语法来引用消息负载中的字段，以便动态选择要插入的集合。