Parsing Apache Log Entries with AWStats

Oct 13, 2025 by wbrum.org 6 views

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Introduction

Apache's LogFormat is a powerful tool for customizing log file formats. However, when working with third-party tools like AWStats, it can be challenging to parse log entries due to differences in formatting. In this article, we will explore the LogFormat directive and provide a solution for parsing Apache log entries with AWStats.

Understanding LogFormat

LogFormat is a directive in Apache's configuration file that allows you to customize the format of log entries. It uses a combination of format specifiers and escape sequences to define the structure of log entries. The format specifiers are used to extract specific information from the log entry, such as the client IP address, request method, and response status code.

Format Specifiers

Format specifiers are used to extract specific information from the log entry. Some common format specifiers include:

%v: Virtual host name
%h: Host name
%a: Client IP address
%l: Remote log name
%u: Remote user
%t: Timestamp
%r: Request line
%>s: Response status code
%O: Output bytes
%{Referer}i: Referer URL
%{User-Agent}i: User agent string

Escape Sequences

Escape sequences are used to escape special characters in the format specifiers. Some common escape sequences include:

\%: Escapes the % character
\Q: Quotes the following string
\E: Ends the quoted string

Parsing Apache Log Entries with AWStats

AWStats is a popular web analytics tool that requires a specific log format to parse log entries. However, Apache's LogFormat directive can produce log entries with different formatting, making it challenging to parse with AWStats.

Solution

To parse Apache log entries with AWStats, we need to modify the LogFormat directive to produce log entries with a consistent format. One solution is to use the %a format specifier instead of %h and %a together.

LogFormat=%v:%p [%a]:%{remote}p %l %u %t "%r" %>s %O "%{Referer}i" "%{User-Agent}i"

However, this will not work with AWStats, as it requires spaces everywhere. To fix this, we need to modify the AWStats configuration file to parse the log entries correctly.

Modifying AWStats Configuration

To modify the AWStats configuration file, we need to add the following lines to the awstats.pl file:

$LogFormatString =~ s/%vh/%virtualname/g;
$LogFormatString =~ s/%v(\s)/%virtualname$1/g;
$LogFormatString =~ s/%v$/%virtualname/g;
$LogFormatString =~ s/%h(\s)/%host$1/g;
$LogFormatString =~ s/%h$/%host/g;
$LogFormatString =~ s/%l(\s)/%other$1/g;
$LogFormatString =~ s/%l$/%other/g;
$LogFormatString =~ s/\"%u\"/%lognamequot/g;
$LogFormatString =~ s/%u(\s)/%logname$1/g;
$LogFormatString =~ s/%u$/%logname/g;
$LogFormatString =~ s/%t(\s)/%time1$1/g;
$LogFormatString =~ s/%t$/%time1/g;
$LogFormatString =~ s/\"%r\"/%methodurl/g;
$LogFormatString =~ s/%>s/%code/g;
$LogFormatString =~ s/%b(\s)/%bytesd$1/g;
$LogFormatString =~ s/%b$/%bytesd/g;
$LogFormatString =~ s/\"%\{Referer}i\"/%refererquot/g;
$LogFormatString =~ s/\"%\{User-Agent}i\"/%uaquot/g;
$LogFormatString =~ s/%\{mod_gzip_input_size}n/%gzipin/g;
$LogFormatString =~ s/%\{mod_gzip_output_size}n/%gzipout/g;
$LogFormatString =~ s/%\{mod_gzip_compression_ratio}n/%gzipratio/g;
$LogFormatString =~ s/${%\{ratio}n}$/%deflateratio/g;

This will modify the LogFormat directive to produce log entries with a consistent format that can be parsed by AWStats.

Conclusion

In this article, we explored the LogFormat directive and provided a solution for parsing Apache log entries with AWStats. By modifying the LogFormat directive and AWStats configuration file, we can produce log entries with a consistent format that can be parsed by AWStats. This will enable us to use AWStats with Apache's custom log format, making it easier to analyze web traffic and improve website performance.

Additional Tips

Make sure to test the modified LogFormat directive and AWStats configuration file to ensure that they work correctly.
Consider using a log format that is compatible with AWStats to avoid modifying the LogFormat directive and AWStats configuration file.
If you are using a custom log format, make sure to document it clearly so that others can understand it.

References

Apache LogFormat Directive: https://httpd.apache.org/docs/2.4/mod/mod_log_config.html#logformat
AWStats Configuration File: https://awstats.sourceforge.io/docs/awstats_config.html
AWStats Log Format: https://awstats.sourceforge.io/docs/awstats_logformat.html

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Q: What is LogFormat in Apache?

A: LogFormat is a directive in Apache's configuration file that allows you to customize the format of log entries. It uses a combination of format specifiers and escape sequences to define the structure of log entries.

Q: Why do I need to modify the LogFormat directive?

A: You need to modify the LogFormat directive to produce log entries with a consistent format that can be parsed by AWStats. AWStats requires a specific log format to parse log entries, and Apache's LogFormat directive can produce log entries with different formatting.

Q: What are format specifiers in LogFormat?

A: Format specifiers are used to extract specific information from the log entry. Some common format specifiers include %v (virtual host name), %h (host name), %a (client IP address), %l (remote log name), %u (remote user), %t (timestamp), %r (request line), %>s (response status code), %O (output bytes), %{Referer}i (referer URL), and %{User-Agent}i (user agent string).

Q: What are escape sequences in LogFormat?

A: Escape sequences are used to escape special characters in the format specifiers. Some common escape sequences include \% (escapes the % character), \Q (quotes the following string), and \E (ends the quoted string).

Q: How do I modify the LogFormat directive to produce log entries with a consistent format?

A: To modify the LogFormat directive, you need to add the following lines to the awstats.pl file:

$LogFormatString =~ s/%vh/%virtualname/g;
$LogFormatString =~ s/%v(\s)/%virtualname$1/g;
$LogFormatString =~ s/%v$/%virtualname/g;
$LogFormatString =~ s/%h(\s)/%host$1/g;
$LogFormatString =~ s/%h$/%host/g;
$LogFormatString =~ s/%l(\s)/%other$1/g;
$LogFormatString =~ s/%l$/%other/g;
$LogFormatString =~ s/\"%u\"/%lognamequot/g;
$LogFormatString =~ s/%u(\s)/%logname$1/g;
$LogFormatString =~ s/%u$/%logname/g;
$LogFormatString =~ s/%t(\s)/%time1$1/g;
$LogFormatString =~ s/%t$/%time1/g;
$LogFormatString =~ s/\"%r\"/%methodurl/g;
$LogFormatString =~ s/%>s/%code/g;
$LogFormatString =~ s/%b(\s)/%bytesd$1/g;
$LogFormatString =~ s/%b$/%bytesd/g;
$LogFormatString =~ s/\"%\{Referer}i\"/%refererquot/g;
$LogFormatString =~ s/\"%\{User-Agent}i\"/%uaquot/g;
$LogFormatString =~ s/%\{mod_gzip_input_size}n/%gzipin/g;
$LogFormatString =~ s/%\{mod_gzip_output_size}n/%gzipout/g;
$LogFormatString =~ s/%\{mod_gzip_compression_ratio}n/%gzipratio/g;
$LogFormatString =~ s/${%\{ratio}n}$/%deflateratio/g;

Q: What are the benefits of modifying the LogFormat directive?

A: Modifying the LogFormat directive allows you to produce log entries with a consistent format that can be parsed by AWStats. This enables you to use AWStats with Apache's custom log format, making it easier to analyze web traffic and improve website performance.

Q: What are some additional tips for working with LogFormat?

A: Some additional tips for working with LogFormat include:

Make sure to test the modified LogFormat directive and AWStats configuration file to ensure that they work correctly.
Consider using a log format that is compatible with AWStats to avoid modifying the LogFormat directive and AWStats configuration file.
If you are using a custom log format, make sure to document it clearly so that others can understand it.

Q: Where can I find more information about LogFormat and AWStats?

A: You can find more information about LogFormat and AWStats on the following websites:

Apache LogFormat Directive: https://httpd.apache.org/docs/2.4/mod/mod_log_config.html#logformat
AWStats Configuration File: https://awstats.sourceforge.io/docs/awstats_config.html
AWStats Log Format: https://awstats.sourceforge.io/docs/awstats_logformat.html