feature: supported zipkin plugin.

COPYRIGHT

@@ -239,3 +239,44 @@ Redistributions in binary form must reproduce the above copyright notice, this l
 
 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
+%%%%%%%%%
+
+opentracing-openresty
+
+https://github.com/iresty/opentracing-openresty
+
+Apache License 2
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+   http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+
+%%%%%%%%%
+
+kong-plugin-zipkin
+
+https://github.com/Kong/kong-plugin-zipkin
+
+Copyright 2018-2019 Kong Inc.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+   http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+
+%%%%%%%%%

conf/config.yaml

@@ -19,8 +19,9 @@ plugins:                        # plugin list
   - example-plugin
   - limit-req
   - limit-count
+  - limit-conn
   - key-auth
   - prometheus
-  - limit-conn
   - node-status
   - jwt-auth
+  - zipkin

doc/plugins/zipkin.md

@@ -0,0 +1,95 @@
+# Summary
+- [**Name**](#name)
+- [**Attributes**](#attributes)
+- [**How To Enable**](#how-to-enable)
+- [**Test Plugin**](#test-plugin)
+- [**Disable Plugin**](#disable-plugin)
+
+
+## Name
+
+[Zipkin](https://github.com/openzipkin/zipkin) is a OpenTracing plugin.
+
+It's also works with `Apache SkyWalking`, which is support Zipkin v1/v2 format.
+
+## Attributes
+
+* `endpoint`: the http endpoint of Ziplin, for example: `http://127.0.0.1:9411/api/v2/spans`.
+
+* `sample_ratio`: the ratio of sample, the minimum is 0.00001, the maximum is 1.
+
+## How To Enable
+
+Here's an example, enable the zipkin plugin on the specified route:
+
+```shell
+curl http://127.0.0.1:9080/apisix/admin/routes/1 -X PUT -d '
+{
+	"methods": ["GET"],
+	"uri": "/index.html",
+	"plugins": {
+		"zipkin": {
+			"endpoint": "http://127.0.0.1:9411/api/v2/spans",
+			"sample_ratio": 1
+		}
+	},
+	"upstream": {
+		"type": "roundrobin",
+		"nodes": {
+			"39.97.63.215:80": 1
+		}
+	}
+}'
+```
+
+## Test Plugin
+
+### run the Zipkin instance
+
+e.g. using docker:
+
+```
+sudo docker run -d -p 9411:9411 openzipkin/zipkin
+```
+
+Here is a test example:
+
+```shell
+$ curl http://127.0.0.1:9080/index.html
+HTTP/1.1 200 OK
+...
+```
+
+Then you can use a browser to access the webUI of Zipkin:
+
+```
+http://127.0.0.1:9411/zipkin
+```
+
+![](../../doc/images/plugin/zipkin-1.png)
+
+![](../../doc/images/plugin/zipkin-2.png)
+
+## Disable Plugin
+
+When you want to disable the zipkin plugin, it is very simple,
+ you can delete the corresponding json configuration in the plugin configuration,
+  no need to restart the service, it will take effect immediately:
+
+```shell
+$ curl http://127.0.0.1:2379/v2/keys/apisix/routes/1 -X PUT -d value='
+{
+	"methods": ["GET"],
+	"uri": "/index.html",
+	"plugins": {
+	},
+	"upstream": {
+		"type": "roundrobin",
+		"nodes": {
+			"39.97.63.215:80": 1
+		}
+	}
+}'
+```
+
+The zipkin plugin has been disabled now. It works for other plugins.

lua/apisix/core/request.lua

@@ -2,12 +2,15 @@
 
 local ngx = ngx
 local get_headers = ngx.req.get_headers
-
+local tonumber = tonumber
 
 local _M = {version = 0.1}
 
 
 local function _headers(ctx)
+    if not ctx then
+        ctx = ngx.ctx.api_ctx
+    end
     local headers = ctx.headers
     if not headers then
         headers = get_headers()
@@ -20,6 +23,9 @@ _M.headers = _headers
 
 
 function _M.header(ctx, name)
+    if not ctx then
+        ctx = ngx.ctx.api_ctx
+    end
     return _headers(ctx)[name]
 end
 
@@ -28,15 +34,29 @@ end
 -- so if there is a load balancer between downstream client and APISIX,
 -- this function will return the ip of load balancer.
 function _M.get_ip(ctx)
+    if not ctx then
+        ctx = ngx.ctx.api_ctx
+    end
     return ctx.var.realip_remote_addr or ctx.var.remote_addr or ''
 end
 
 
 -- get remote address of downstream client,
 -- in cases there is a load balancer between downstream client and APISIX.
 function _M.get_remote_client_ip(ctx)
+    if not ctx then
+        ctx = ngx.ctx.api_ctx
+    end
     return ctx.var.remote_addr or ''
 end
 
 
+function _M.get_remote_client_port(ctx)
+    if not ctx then
+        ctx = ngx.ctx.api_ctx
+    end
+    return tonumber(ctx.var.remote_port)
+  end
+
+
 return _M

lua/apisix/core/response.lua

@@ -10,7 +10,8 @@ local type = type
 local ngx_exit = ngx.exit
 local insert_tab = table.insert
 local concat_tab = table.concat
-
+local str_sub = string.sub
+local tonumber = tonumber
 
 local _M = {version = 0.1}
 
@@ -78,4 +79,9 @@ function _M.set_header(...)
 end
 
 
+function _M.get_upstream_status(ctx)
+    -- $upstream_status maybe including mutiple status, only need the last one
+    return tonumber(str_sub(ctx.var.upstream_status or "", -3))
+end
+
 return _M

lua/apisix/plugins/zipkin.lua

@@ -0,0 +1,165 @@
+local core = require("apisix.core")
+local new_tracer = require("opentracing.tracer").new
+local zipkin_codec = require("apisix.plugins.zipkin.codec")
+local new_random_sampler = require("apisix.plugins.zipkin.random_sampler").new
+local new_reporter = require("apisix.plugins.zipkin.reporter").new
+local ngx = ngx
+local pairs = pairs
+
+local plugin_name = "zipkin"
+
+
+-- You can follow this document to write schema:
+-- https://github.com/Tencent/rapidjson/blob/master/bin/draft-04/schema
+-- rapidjson not supported `format` in draft-04 yet
+local schema = {
+    type = "object",
+    properties = {
+        endpoint = {type = "string"},
+        sample_ratio = {type = "number", minimum = 0.00001, maximum = 1}
+    },
+    required = {"endpoint", "sample_ratio"}
+}
+
+
+local _M = {
+    version = 0.1,
+    priority = -1000, -- last running plugin
+    name = plugin_name,
+    schema = schema,
+}
+
+
+function _M.check_schema(conf)
+    return core.schema.check(schema, conf)
+end
+
+
+local function create_tracer(conf)
+    local tracer = new_tracer(new_reporter(conf), new_random_sampler(conf))
+    tracer:register_injector("http_headers", zipkin_codec.new_injector())
+    tracer:register_extractor("http_headers", zipkin_codec.new_extractor())
+    return tracer
+end
+
+local function report2endpoint(premature, reporter)
+    if premature then
+        return
+    end
+
+    local ok, err = reporter:flush()
+    if not ok then
+        core.log.error("reporter flush ", err)
+        return
+    end
+
+    core.log.info("report2endpoint ok")
+end
+
+
+function _M.rewrite(conf, ctx)
+    local tracer = core.lrucache.plugin_ctx(plugin_name, ctx,
+                                            create_tracer, conf)
+
+    ctx.opentracing_sample = tracer.sampler:sample()
+    if not ctx.opentracing_sample then
+        return
+    end
+
+    local wire_context = tracer:extract("http_headers",
+                                        core.request.headers(ctx))
+
+    local start_timestamp = ngx.req.start_time()
+    local request_span = tracer:start_span("apisix.request", {
+        child_of = wire_context,
+        start_timestamp = start_timestamp,
+        tags = {
+            component = "apisix",
+            ["span.kind"] = "server",
+            ["http.method"] = ctx.var.method,
+            ["http.url"] = ctx.var.request_uri,
+             -- TODO: support ipv6
+            ["peer.ipv4"] = core.request.get_remote_client_ip(ctx),
+            ["peer.port"] = core.request.get_remote_client_port(ctx),
+        }
+    })
+
+    ctx.opentracing = {
+        tracer = tracer,
+        wire_context = wire_context,
+        request_span = request_span,
+        rewrite_span = nil,
+        access_span = nil,
+        proxy_span = nil,
+    }
+
+    local request_span = ctx.opentracing.request_span
+    ctx.opentracing.rewrite_span = request_span:start_child_span(
+                                            "apisix.rewrite", start_timestamp)
+    ctx.REWRITE_END_TIME = tracer:time()
+    ctx.opentracing.rewrite_span:finish(ctx.REWRITE_END_TIME)
+end
+
+function _M.access(conf, ctx)
+    if not ctx.opentracing_sample then
+        return
+    end
+
+    local opentracing = ctx.opentracing
+
+    opentracing.access_span = opentracing.request_span:start_child_span(
+            "apisix.access", ctx.REWRITE_END_TIME)
+
+    local tracer = opentracing.tracer
+
+    ctx.ACCESS_END_TIME = tracer:time()
+    opentracing.access_span:finish(ctx.ACCESS_END_TIME)
+
+    opentracing.proxy_span = opentracing.request_span:start_child_span(
+            "apisix.proxy", ctx.ACCESS_END_TIME)
+
+    -- send headers to upstream
+    local outgoing_headers = {}
+    tracer:inject(opentracing.proxy_span, "http_headers", outgoing_headers)
+    for k, v in pairs(outgoing_headers) do
+        core.response.set_header(k, v)
+    end
+end
+
+
+function _M.header_filter(conf, ctx)
+    if not ctx.opentracing_sample then
+        return
+    end
+
+    local opentracing = ctx.opentracing
+
+    ctx.HEADER_FILTER_END_TIME = opentracing.tracer:time()
+    opentracing.body_filter_span = opentracing.proxy_span:start_child_span(
+            "apisix.body_filter", ctx.HEADER_FILTER_END_TIME)
+end
+
+
+function _M.log(conf, ctx)
+    if not ctx.opentracing_sample then
+        return
+    end
+
+    local opentracing = ctx.opentracing
+
+    local log_end_time = opentracing.tracer:time()
+    opentracing.body_filter_span:finish(log_end_time)
+
+    local upstream_status = core.response.get_upstream_status(ctx)
+    opentracing.request_span:set_tag("http.status_code", upstream_status)
+    opentracing.proxy_span:finish(log_end_time)
+    opentracing.request_span:finish(log_end_time)
+
+    local reporter = opentracing.tracer.reporter
+    local ok, err = ngx.timer.at(0, report2endpoint, reporter)
+    if not ok then
+        core.log.error("failed to create timer: ", err)
+    end
+end
+
+return _M