#access-log
Posts
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Digging into Apache httpd's Source 16: Logging — Access Logs, Error Logs, and Wrapping Up the Series
How httpd's two kinds of log are actually written, followed through the source. How one ap_log_rerror() call is filtered by a macro before anything runs, how module_index lets LogLevel differ per module, how ErrorLogFormat and LogFormat strings become arrays of function pointers, exactly when the log_transaction hook fires, and how a piped log program is restarted — all checked with examples, followed by a look back over the 16-part series.
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Digging into Tomcat's Source 8: Pipelines and Valves — The Processing Chain on Every Container
What does one <Valve> line in server.xml become in the source? We look at the pipeline each of Engine, Host, Context and Wrapper owns, the four basic valves at the ends that pick the next container, how a valve stops a request by not calling the next one, ErrorReportValve that draws the error page, the access log that is only written after the response has gone out, and the RemoteIpValve trap — checking it all against the source with our own valves hung on three containers.