feature: add opentelemetry plugin. (apache#3891)

apisix/plugins/opentelemetry.lua

@@ -61,7 +61,7 @@ local attr_schema = {
         trace_id_source = {
             type = "string",
             enum = {"x-request-id", "random"},
-            description = "alternate use x-request-id as trace id",
+            description = "the source of trace id",
             default = "random",
         },
         resource = {
@@ -307,11 +307,14 @@ function _M.access(conf, api_ctx)
 end
 
 
-function _M.body_filter(conf, ctx)
+function _M.body_filter(conf, api_ctx)
     if ngx.arg[2] then
-        local upstream_status = core.response.get_upstream_status(ctx)
+        local upstream_status = core.response.get_upstream_status(api_ctx)
+        local ctx = context:current();
+        ctx:detach()
+
         -- get span from current context
-        local span = context:current():span()
+        local span = ctx:span()
         if upstream_status and upstream_status >= 500 then
             span:set_status(span_status.error,
                             "upstream response status: " .. upstream_status)
@@ -322,4 +325,19 @@ function _M.body_filter(conf, ctx)
 end
 
 
+function _M.log(conf, api_ctx)
+    local ctx = context:current();
+    if ctx then
+        -- get span from current context
+        local span = ctx:span()
+        if upstream_status and upstream_status >= 500 then
+            span:set_status(span_status.error,
+                    "upstream response status: " .. upstream_status)
+        end
+
+        span:finish()
+    end
+end
+
+
 return _M

docs/en/latest/plugins/opentelemetry.md

@@ -47,8 +47,8 @@ Just support reporting in `HTTP` with `Content-Type=application/x-protobuf`, the
 | sampler.options.root.name | string | optional | always_off | ["always_on", "always_off", "trace_id_ratio"] | sampling strategy
 | sampler.options.root.options | object | optional | {fraction = 0} | | sampling strategy parameters
 | sampler.options.root.options.fraction | number | optional | 0 | [0, 1] | trace_id_ratio fraction
-| additional_attributes | array[string] | optional | | | append to trace span attributes
-| additional_attributes[0] | string | required | | | key of ctx.var
+| additional_attributes | array[string] | optional | | | attributes (variable and its value) which will be appended to the trace span
+| additional_attributes[0] | string | required | | | APISIX or Nginx variable, like `http_header` or `route_id`
 
 ## How To Enable
 
@@ -94,7 +94,7 @@ We can set the collecting by specifying the configuration in `conf/config.yaml`.
 
 | Name         | Type   | Default  | Description                                                          |
 | ------------ | ------ | -------- | ----------------------------------------------------- |
-| trace_id_source | enum | random | alternate use x-request-id as trace id, valid value is `random` or `x-request-id`, if use `x-request-id`, please make sure it match regex pattern `[0-9a-f]{32}` |
+| trace_id_source | enum | random | the source of trace id, the valid value is `random` or `x-request-id`. If `x-request-id` is set, the value of `x-request-id` request header will be used as trace id. Please make sure it match regex pattern `[0-9a-f]{32}` |
 | resource | object |   | additional [resource](https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/resource/sdk.md) append to trace |
 | collector | object | {address = "127.0.0.1:4317", request_timeout = 3} | otlp collector |
 | collector.address | string | 127.0.0.1:4317 | collector address |

docs/zh/latest/plugins/opentelemetry.md

@@ -47,9 +47,8 @@ title: opentelemetry
 | sampler.options.root.name | string | 可选 | always_off | ["always_on", "always_off", "trace_id_ratio"] | 采样算法
 | sampler.options.root.options | object | 可选 | {fraction = 0} | | 采样算法参数
 | sampler.options.root.options.fraction | number | 可选 | 0 | [0, 1] | trace_id_ratio 采样算法的百分比
-| tags | array[object] | 可选 | | | 追加到 trace span 的属性
-| tags.position | string | 必须 | | ["http", "arg", "cookie"] | 变量的位置
-| tags.name | string | 必须 | | | 变量的名称
+| additional_attributes | array[string] | optional | | | 追加到 trace span 的额外属性（变量名为 key，变量值为 value）
+| additional_attributes[0] | string | required | | | APISIX or Nginx 变量，例如 `http_header` or `route_id`
 
 ## 如何启用