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  16. NOTICE

Apache SkyWalking Nginx Agent

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SkyWalking Nginx Agent provides the native tracing capability for Nginx powered by Nginx LUA module.

This agent follows the SkyWalking tracing and header protocol. It reports tracing data to SkyWalking APM through HTTP protocol. All HTTP 1.1 requests go through Nginx could be collected by this agent.

Setup Doc

http {
    lua_package_path "/Path/to/.../skywalking-nginx-lua/lib/?.lua;;";

    # Buffer represents the register inform and the queue of the finished segment
    lua_shared_dict tracing_buffer 100m;

    # Init is the timer setter and keeper
    # Setup an infinite loop timer to do register and trace report.
    init_worker_by_lua_block {
        local metadata_buffer = ngx.shared.tracing_buffer

        -- Set service name
        metadata_buffer:set('serviceName', 'User Service Name')
        -- Instance means the number of Nginx deployment, does not mean the worker instances
        metadata_buffer:set('serviceInstanceName', 'User Service Instance Name')
        -- type 'boolean', mark the entrySpan include host/domain
        metadata_buffer:set('includeHostInEntrySpan', false)

        -- set random seed

        -- If there is a bug of this `tablepool` implementation, we can
        -- disable it in this way
        -- require("skywalking.util").disable_tablepool()

        skywalking_tracer = require("skywalking.tracer")

        location /ingress {
            default_type text/html;

            rewrite_by_lua_block {
                -- NOTICE, this should be changed manually
                -- This variable represents the upstream logic address
                -- Please set them as service logic name or DNS name
                -- Currently, we can not have the upstream real network address
                skywalking_tracer:start("upstream service")
                -- If you want correlation custom data to the downstream service
                -- skywalking_tracer:start("upstream service", {custom = "custom_value"})

            -- Target upstream service

            body_filter_by_lua_block {
                if ngx.arg[2] then

            log_by_lua_block {


Please head to the releases page to download a release of Apache SkyWalking.

  • 0.1.0 release requires SkyWalking 7
  • 0.2.0+ releases require SkyWalking 8

Compatible backend

SkyWalking OAP begins to support LUA agent in 7.0.0 release.

You could choose master branch before the official 7.0.0 release.

Set up dev env

Debug Startup

By using the /examples/nginx.conf, you could start the Nginx with LUA module or OpenResty. Such as nginx -c /path/to/skywalking-nginx-lua/examples/nginx.conf Then you could

  1. See the instance properties update logs happens on the console log.
2020/04/04 15:15:37 [debug] 12089#1446111: *4 [lua] content_by_lua(nginx.conf:175):4: Instance report request = {"service":"User Service Name","serviceInstance":"User Service Instance Name","properties":[{"language":"Lua"}]}
2020/04/04 15:15:37 [debug] 12089#1446111: *2 [lua] client.lua:89: reportServiceInstance(): Instance report response = {}
  1. See the heartbeat logs happens after the register logs
2020/04/04 15:15:40 [debug] 12089#1446111: *4 [lua] content_by_lua(nginx.conf:188):3: KeepAlive request = {"service":"User Service Name","serviceInstance":"User Service Instance Name"}
  1. Access the then you could see the tracing happens and reported spans in the logs.
2020/04/04 15:15:46 [debug] 12089#1446111: *11 [lua] tracer.lua:83: prepareForReport(): segment = {"traceId":"1585984546953.410917649.45972","serviceInstance":"User Service Instance Name","spans":[{"operationName":"\/tier2\/lb","startTime":1585984546967,"endTime":1585984546968,"spanType":"Exit","spanId":1,"isError":false,"parentSpanId":0,"componentId":6000,"peer":"backend service","spanLayer":"Http"},{"operationName":"\/tier2\/lb","startTime":1585984546967,"tags":[{"key":"http.method","value":"GET"},{"key":"http.params","value":"http:\/\/\/tier2\/lb"}],"endTime":1585984546968,"spanType":"Entry","spanId":0,"isError":false,"parentSpanId":-1,"componentId":6000,"refs":[{"traceId":"1585984546953.410917649.45972","networkAddressUsedAtPeer":"upstream service","parentEndpoint":"\/ingress","parentServiceInstance":"User Service Instance Name","parentSpanId":1,"parentService":"User Service Name","parentTraceSegmentId":"1585984546953.410917649.45972","refType":"CrossProcess"}],"spanLayer":"Http"}],"service":"User Service Name","traceSegmentId":"1585984546967.449397702.9959"}
2020/04/04 15:15:46 [debug] 12089#1446111: *11 [lua] tracer.lua:87: prepareForReport(): segment buffer size = 1
2020/04/04 15:15:46 [debug] 12089#1446111: *8 [lua] tracer.lua:83: prepareForReport(): segment = {"traceId":"1585984546953.410917649.45972","serviceInstance":"User Service Instance Name","spans":[{"operationName":"\/ingress","startTime":1585984546953,"endTime":1585984546968,"spanType":"Exit","spanId":1,"isError":false,"parentSpanId":0,"componentId":6000,"peer":"upstream service","spanLayer":"Http"},{"operationName":"\/ingress","startTime":1585984546953,"tags":[{"key":"http.method","value":"GET"},{"key":"http.params","value":"http:\/\/localhost\/ingress"}],"endTime":1585984546968,"spanType":"Entry","spanId":0,"parentSpanId":-1,"isError":false,"spanLayer":"Http","componentId":6000}],"service":"User Service Name","traceSegmentId":"1585984546953.410917649.45972"}

Local Development and Unit Tests

All codes in the lib/skywalking require the *_test.lua to do the UnitTest. To run that, you need to install

  • Lua 5.3
  • LuaRocks

The following libs are required in runtime or test cases, please use LuaRocks to install them.

  • lua-cjson. NOTICE, some platforms such as MacOS 10.15 may have issue with the latest release of this lib, consider to install an old release.(luarocks install lua-cjson 2.1.0-1)
  • luaunit
  • lua-resty-jit-uuid


This LUA tracing lib is originally designed for Nginx+LUA/OpenResty ecosystems. But we write it to support more complex cases. If you just use this in the Ngnix, Setup Doc should be good enough. The following APIs are for developers or using this lib out of the Nginx case.

Nginx APIs

  • startTimer, require("skywalking.client"):startBackendTimer(""). Start the backend timer. This timer register the metadata and report traces to the backend.
  • destroyBackendTimer, require("skywalking.client"):destroyBackendTimer(). Stop the timer created by startBackendTimer, and clean unreported data.
  • start, require("skywalking.tracer"):start("upstream service", correlation). Begin the tracing before the upstream begin. The custom data (table type) can be injected as the second parameter, and then they will be propagated to the downstream service.
  • finish, require("skywalking.tracer"):finish(). Finish the tracing for this HTTP request.
  • prepareForReport, require("skywalking.tracer"):prepareForReport(). Prepare the finished segment for further report.

Tracing APIs at LUA level

TracingContext is the entrance API for lua level tracing.

  •, serviceInstID), create an active tracing context.
  • TracingContext.newNoOP(), create a no OP tracing context.
  • TracingContext.drainAfterFinished(), fetch the segment includes all finished spans.

Create 2 kinds of span

  • TracingContext.createEntrySpan(operationName, parent, contextCarrier)
  • TracingContext.createExitSpan(operationName, parent, peer, contextCarrier)

Contact Us

  • Submit an issue with [NIGNX-LUA] as the issue title prefix.
  • Mail list: Mail to, follow the reply to subscribe the mail list.
  • Join skywalking channel at Apache Slack. If the link is not working, find the latest one at Apache INFRA WIKI.
  • QQ Group: 392443393(2000/2000, not available), 901167865(available)

Release Guide

All committers should follow Release Guide to publish the official release.


Apache 2.0