From e9e53e8152b92c2daa16a27e411ebf318534b4a6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E7=BD=97=E6=B3=BD=E8=BD=A9?= <spacewanderlzx@gmail.com>
Date: Wed, 9 Feb 2022 19:54:38 +0800
Subject: [PATCH] refactor: mv the var mqtt_client_id to plugin level (#6241)

---
 apisix/core/ctx.lua                  |  5 -----
 apisix/stream/plugins/mqtt-proxy.lua |  5 +++++
 docs/en/latest/apisix-variable.md    | 26 +++++++++++++-------------
 3 files changed, 18 insertions(+), 18 deletions(-)

diff --git a/apisix/core/ctx.lua b/apisix/core/ctx.lua
index a954e750..af8672d9 100644
--- a/apisix/core/ctx.lua
+++ b/apisix/core/ctx.lua
@@ -148,7 +148,6 @@ do
         balancer_ip = true,
         balancer_port = true,
         consumer_name = true,
-        mqtt_client_id = true,
         route_id = true,
         route_name = true,
         service_id = true,
@@ -254,10 +253,6 @@ function _M.register_var(name, getter)
         error("the getter of registered var should be a function")
     end
 
-    if apisix_var_names[name] then
-        error(name .. " is registered")
-    end
-
     apisix_var_names[name] = getter
 end
 
diff --git a/apisix/stream/plugins/mqtt-proxy.lua b/apisix/stream/plugins/mqtt-proxy.lua
index 3a285890..2c421dcc 100644
--- a/apisix/stream/plugins/mqtt-proxy.lua
+++ b/apisix/stream/plugins/mqtt-proxy.lua
@@ -23,6 +23,11 @@ local str_byte  = string.byte
 local str_sub   = string.sub
 
 
+core.ctx.register_var("mqtt_client_id", function(ctx)
+    return ctx.mqtt_client_id
+end)
+
+
 local schema = {
     type = "object",
     properties = {
diff --git a/docs/en/latest/apisix-variable.md b/docs/en/latest/apisix-variable.md
index 9591010e..d6254b82 100644
--- a/docs/en/latest/apisix-variable.md
+++ b/docs/en/latest/apisix-variable.md
@@ -26,18 +26,18 @@ additional variables.
 
 List in alphabetical order:
 
-|   Variable Name  |      Description        | Example      |
-|------------------|-------------------------| ---------    |
-| balancer_ip      | the IP of picked upstream server | 1.1.1.1 |
-| balancer_port    | the port of picked upstream server | 80 |
-| consumer_name    | username of `consumer` |   |
-| graphql_name     | the [operation name](https://graphql.org/learn/queries/#operation-name) of GraphQL | HeroComparison |
-| graphql_operation     | the operation type of GraphQL | mutation  |
-| graphql_root_fields     | the top level fields of GraphQL | ["hero"] |
-| mqtt_client_id   | the client id in MQTT protocol |   |
-| route_id         | id of `route`          |   |
-| route_name       | name of `route`        |   |
-| service_id       | id of `service`        |   |
-| service_name     | name of `service`      |   |
+|   Variable Name  |  Origin | Description        | Example      |
+|------------------|---------|--------------------| ---------    |
+| balancer_ip      | core    | the IP of picked upstream server | 1.1.1.1 |
+| balancer_port    | core    | the port of picked upstream server | 80 |
+| consumer_name    | core    | username of `consumer` |   |
+| graphql_name     | core    | the [operation name](https://graphql.org/learn/queries/#operation-name) of GraphQL | HeroComparison |
+| graphql_operation     | core    | the operation type of GraphQL | mutation  |
+| graphql_root_fields     | core    | the top level fields of GraphQL | ["hero"] |
+| mqtt_client_id   | mqtt-proxy | the client id in MQTT protocol |   |
+| route_id         | core    | id of `route`          |   |
+| route_name       | core    | name of `route`        |   |
+| service_id       | core    | id of `service`        |   |
+| service_name     | core    | name of `service`      |   |
 
 You can also [register your own variable](./plugin-develop.md#register-custom-variable).