LogLineParser

LogLineParser is a simple parser of Apache access log. It parses a line of Apache access log and turns it into an array of strings or a Hash object. And from the command line, you can use it as a conversion tool of file format (to CSV or TSV) or as a filtering tool of access records.

Installation

Add this line to your application's Gemfile:

gem 'log_line_parser'

And then execute:

$ bundle

Or install it yourself as:

$ gem install log_line_parser

If you have millions of records to be parsed

I recommend you to use JRuby (version >= 9.1.8), because it is significantly faster than MRI.

When you use JRuby, you have to set RUBYOPT environment variable at first. For example:

# For Bash or Zsh
$ RUBYOPT='-Xcompile.invokedynamic=true'
$ export RUBYOPT

Or

# For MS Windows
set RUBYOPT=-Xcompile.invokedynamic=true

Usage

As a converter

require 'log_line_parser'

line = '192.168.3.4 - - [07/Feb/2016: ... ] ...'
LogLineParser.to_array(line)
# => ["192.168.3.4", "-", "-", "07/Feb/2016: ... ", ... ]

Or in limited cases, parsers corresponding to certain LogFormats are available:

require 'log_line_parser'

line = '192.168.3.4 - quidam [07/Feb/2016:07:39:42 +0900] "GET /index.html HTTP/1.1" 200 432 "http://www.example.org/start.html" "Mozilla/5.0 (X11; U; Linux i686; ja-JP; rv:1.7.5) Gecko/20041108 Firefox/1.0"'
LogLineParser::CombinedLogParser.to_hash(line)
# => {
#   "%h" => "192.168.3.4",
#   "%l" => "-",
#   "%u" => "quidam",
#   "%t" => "07/Feb/2016:07:39:42 +0900",
#   "%r" => "GET /index.html HTTP/1.1",
#   "%>s" => "200",
#   "%b" => "432",
#   "%{Referer}i" => "http://www.example.org/start.html",
#   "%{User-agent}i" => "Mozilla/5.0 (X11; U; Linux i686; ja-JP; rv:1.7.5) Gecko/20041108 Firefox/1.0",
#   "%m" => "GET",
#   "%H" => "HTTP/1.1",
#   "%U%q" => "/index.html"
# }

Three parsers are predefined for such cases:

LogLineParser::CommonLogParser

For Common Log Format (CLF)

LogLineParser::CommonLogWithVHParser

For Common Log Format with Virtual Host

LogLineParser::CombinedLogParser

For NCSA extended/combined log format

Defining a parser

You can define your own parser as in the following example:

require 'log_line_parser'

RefererLogParser = LogLineParser.parser('"%r" %>s %b %{Referer}i -> %U')

line = '"GET /index.html HTTP/1.1" 200 432 http://www.example.org/start.html -> /index.html'

RefererLogParser.to_hash(line)
# => {
#   "%r" => "GET /index.html HTTP/1.1",
#   "%>s" => "200",
#   "%b" => "432",
#   "%{Referer}i" => "http://www.example.org/start.html",
#   "->" => "->",
#   "%U" => "/index.html",
#   "%m" => "GET",
#   "%H" => "HTTP/1.1",
#   "%U%q" => "/index.html"
# }

Limitations

• Currently, you should include at least %r, %>s and %b in the format strings passed to LogLineParser.parser.
• If the value of a field is expected to contain a space, such field should be enclosed in double quotes (that means you have to change access log settings).

As a command-line application

The command line tool log_line_parser can be used for two purposes:

1. For converting file formats
2. For picking up log records that satisfy certain criteria

For the first purpose, the tool supports conversion from an Apache log format to CSV or TSV format. And for the second purpose, criteria such as :not_found?(= :status_code_404?) or :access_by_bots? are defined, and you can combine them by writing a configuration file.

For converting file formats

Suppose you have an Apache log file example_combined_log.log, and run the following command in your terminal:

$ log_line_parser example_combined_log.log > expected_combined_log.csv

Then you will get expected_combined_log.csv.

To convert into TSV format:

$ log_line_parser --to=tsv example_combined_log.log > expected_combined_log.tsv

And you will get expected_combined_log.tsv.

For picking up log records

First, you have to prepare a configuration file in YAML format. samples/sample_config.yml is an example.

Second, run the following command if you want to pick up from samples/sample_combined_log.log the log records that meet the definitions in the configuration file:

$ log_line_parser --filter-mode --log-format combined --config=samples/sample_config.yml --output-dir=samples/output samples/sample_combined_log.log

Then the results are in samples/output directory.

Format of configuration file

An example of configurations is below:

---
host_name: www.example.org
resources:
 - /end.html
 - /subdir/big.pdf
match:
 - :access_to_resources?
match_type: any
output_log_name: access-to-two-specific-files
---
host_name: www.example.org
resources:
 - /
match:
 - :access_to_under_resources?
match_type: any
ignore_match:
 - :access_by_bots?
 - :not_found?
output_log_name: all-but-bots-and-not-found
---
host_name: www.example.org
resources:
 - /index.html
match:
 - :access_to_resources?
 - :access_by_bots?
match_type: all
output_log_name: index-page-accessed-by-bot

It contains three configurations, and each of them consists of parameters in the following table:

Parameters	Note
host_name (optional)	Currently, the specified value is compared with the host part of the value of "%{Referer}i".
resources	The values will be compared with the value of "%U%q" field or the path part of the value of "%{Referer}i".
match	The criteria that a log record should satisfy.
ignore_match (optional)	If a log record satisfies any of the criteria listed under this parameter, the record is ignored.
match_type (optional)	The value is "any" (default) or "all". "any" means a log record is picked up if any of the criteria listed under the "match" parameter is satisfied. "all" means all of the criteria must be satisfied for the picking up.
output_log_name	Log records picked up are written in the file specified by this parameter.

Criteria for "match" and "ignore_match" parameters

Available criteria	Note
:access_by_bots?	Access by major web crawlers such as Googlebot or Bingbot.
:access_to_image?	The value of "%U%q" matches /.(?:jpe?g|png|gif|ico|tiff?|bmp|svgz?|webp)$/in
:referred_from_resources?	The path part of the value of "%{Referer}i" matches any of the values of "resources".
:referred_from_under_resources?	The path part of the value of "%{Referer}i" begins with any of the values of "resources".
:access_to_resources?	The value of "%U%q" matches any of the values of "resources".
:access_to_under_resources?	The value of "%U%q" begins with any of the values of "resources".
:partial_content? / :status_code_206?	The value of "%>s" is 206.
:moved_permanently? / :status_code_301?	The value of "%>s" is 301.
:not_modified? / :status_code_304?	The value of "%>s" is 304.
:not_found? / :status_code_404?	The value of "%>s" is 404.
:options_method?	The value of "%m" is OPTIONS
:get_method?	The value of "%m" is GET.
:head_method?	The value of "%m" is HEAD.
:post_method?	The value of "%m" is POST.
:put_method?	The value of "%m" is PUT.
:delete_method?	The value of "%m" is DELETE.
:trace_method?	The value of "%m" is TRACE.
:connect_method?	The value of "%m" is CONNECT.
:patch_method?	The value of "%m" is PATCH.

Default web crawlers

The following web crawlers are set by default and used by Query#access_by_bots?:

• Googlebot
• Googlebot-Mobile
• Mediapartners-Google
• Bingbot
• Slurp
• Baiduspider
• BaiduImagespider
• BaiduMobaider
• YetiBot
• Applebot

Format of bots configuration file

You can specify web crawlers by giving a configuration file to --bots-config option. The following is an example of configuration file:

inherit_default_bots: false
bots:
 - Googlebot
 - Googlebot-Mobile
 - Mediapartners-Google
 - Bingbot
 - Slurp
 - Baiduspider
 - BaiduImagespider
 - BaiduMobaider
 - YetiBot
 - Applebot
bots_re:
 - " bot$"

Parameters	Note
bots (optional)	Names of web crawlers that make Query#access_by_bots? return true when they are included in the value of "%{Referer}i".
inherit_default_bots (optional)	If this option is set to true, the default names of major web crawlers are added to the names specified by bots parameter.
bots_re (optional)	Use this parameter if you want to identify bots by regular expressions.

The values given by the configuration file are compiled into a regular expression, and you can check the expression by invoking the tool as follows:

$ log_line_parser --show-current-settings --bots-config=bots_config.yml

Command line options

The following command options are available.

Short	Long	Description
-c [config_file]	--config [=config_file]	Give a configuration file in yaml format
-b [bots_config_file]	--bots-config [=bots_config_file]	Give a configuration file in yaml format. Default bots: Googlebot, Googlebot-Mobile, Mediapartners-Google, Bingbot, Slurp, Baiduspider, BaiduImagespider, BaiduMobaider, YetiBot, Applebot
-s	--show-current-settings	Show the detail of the current settings
-f	--filter-mode	Mode for choosing log records that satisfy certain criteria
-l [LogFormat]	--log-format [=LogFormat]	Specify LogFormat by giving a LogFormat or one of formats predefined as "common", "common_with_vh", "combined", "moe"
-o [output_dir]	--output-dir [=output_dir]	Specify the output directory for log files
-t [format]	--to [=format]	Specify a format: csv, tsv or ltsv
-e [error_log_file]	--error-log [=error_log_file]	Specify a file for error logging

Development

After checking out the repo, run bin/setup to install dependencies. Then, run bin/console for an interactive prompt that will allow you to experiment. Run bundle exec log_line_parser to use the code located in this directory, ignoring other installed copies of this gem.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release to create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

1. Fork it ( https://github.com/nico-hn/LogLineParser/fork )
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create a new Pull Request