4.2.9 Collecting proxy trace information

Proxy trace information indicates the trace information that is collected in the following cases when the reverse proxy functionality is used:

When processing for connecting to the backend server starts
When processing for connecting to the backend server ends
When processing for forwarding a request to the backend server starts
When processing for receiving a response from the backend server starts

The proxy trace information collection functionality can be used when the HWSRequestLog directive is specified and proxy is specified for the HWSRequestLogType directive. Proxy trace information is useful for understanding the processing status when sending requests to the backend server.

Organization of this subsection

(1) Trace information format

(1) Trace information format

The items below are output for proxy trace information.

Note that in the following coding, server-process-ID is used in the format when the prefork MPM is used in the UNIX version. In place of server-process-ID, server-process-ID:server-thread-ID is displayed for the worker MPM in the UNIX version, and server-thread-ID is displayed in the Windows version.

When connection processing starts

[time]Δ(server-process-ID)Δ(root-application-information)ΔproxyΔconnection-destination-IP-address:connection-destination-port-numberΔ:Δconnect

When connection processing ends (connection successful)

[time]Δ(server-process-ID)Δ(root-application-information)ΔproxyΔconnection-destination-IP-address:connection-destination-port-numberΔ:Δconnect(O)

When connection processing ends (connection failed)

[time]Δ(server-process-ID)Δ(root-application-information)ΔproxyΔconnection-destination-IP-address:connection-destination-port-numberΔ:Δconnect(X)

When request forwarding starts
```
[time]Δ(server-process-ID)Δ(root-application-information)ΔproxyΔconnection-destination-IP-address:connection-destination-port-numberΔ:ΔreqΔsend(type)(Content-Lengthheader-value)
```
One of the following is displayed for type:

CHUNK: Data is forwarded in the chunk format.

CL: Transfer for the size indicated for Content-Length is repeated.

SPOOL: Bodies saved in a temporary file are forwarded in a batch.

If the value for Content-Length does not exist, - is output for header-value.

When response reception processing starts

[time]Δ(process-ID)Δ(root-application-information)ΔproxyΔconnection-destination-IP-address:connection-destination-port-numberΔ:ΔresΔrecv

Legend:

Δ: Space

(Output example)

[Thu Aug 29 11:03:58.639 2013] (21999) (192.168.0.33/250/0x0000000000000001) proxy 192.168.1.5:80 : connect
[Thu Aug 29 11:03:58.639 2013] (21999) (192.168.0.33/250/0x0000000000000001) proxy 192.168.1.5:80 : connect(O)
[Thu Aug 29 11:03:58.639 2013] (21999) (192.168.0.33/250/0x0000000000000001) proxy 192.168.1.5:80 : req send(CL)(4096)
[Thu Aug 29 11:03:58.682 2013] (21999) (192.168.0.33/250/0x0000000000000001) proxy 192.168.1.5:80 : res recv

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