README.md

OpenTelemetry C++ Example

HTTP

This is a simple example that demonstrates tracing an HTTP request from client to server. The example shows several aspects of tracing such as:

• Using the TracerProvider
• Using the GlobalPropagator
• Span Attributes
• Span Events
• Using the ostream exporter
• Nested spans (TBD)
• W3C Trace Context Propagation

Running the example

1. The example uses HTTP server and client provided as part of this repo:

   • HTTP Client
   • HTTP Server

2. Build and Deploy the opentelemetry-cpp as described in INSTALL.md

3. Start the server from the examples/http directory

   $ http_server 8800
    Server is running..Press ctrl-c to exit...

4. In a separate terminal window, run the client to make a single request:

   $ ./http_client 8800
   ...
   ...

5. You should see console exporter output for both the client and server sessions.

   • Client console

   {
     name          : /helloworld
     trace_id      : baa922bc0da6f79d46373371f4416463
     span_id       : 83bed4da7a01267d
     tracestate    :
     parent_span_id: 0000000000000000
     start         : 1620287026111457000
     duration      : 5164400
     description   :
     span kind     : Client
     status        : Unset
     attributes    :
           http.header.Date: Thu, 06 May 2021 07:43:46 GMT
           http.header.Content-Length: 0
           http.status_code: 200
           http.method: GET
           http.header.Host: localhost
           http.header.Content-Type: text/plain
           http.header.Connection: keep-alive
           http.scheme: http
           http.url: h**p://localhost:8800/helloworld
     events        :
     links         :
   
   }

   • Server console

   {
     name          : /helloworld
     trace_id      : baa922bc0da6f79d46373371f4416463
     span_id       : c3e7e23042eb670e
     tracestate    :
     parent_span_id: 83bed4da7a01267d
     start         : 1620287026115443300
     duration      : 50700
     description   :
     span kind     : Server
     status        : Unset
     attributes    :
           http.header.Traceparent: 00-baa922bc0da6f79d46373371f4416463-83bed4da7a01267d-01
           http.header.Accept: */*
           http.request_content_length: 0
           http.header.Host: localhost:8800
           http.scheme: http
           http.client_ip: 127.0.0.1:50792
           http.method: GET
           net.host.port: 8800
           http.server_name: localhost
     events        :
           {
             name          : Processing request
             timestamp     : 1620287026115464000
             attributes    :
           }
     links         :
   
   }

   As seen from example above, trace_id and parent_span_id is propagated from client to server.