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imported>BryanDavis
imported>BryanDavis
(→‎{{anchor|Logs}}Web logs: wordsmithing. This section still needs some information for non-lighttpd webservices (or links out to that documentation elsewhere))
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== {{anchor|Logs}}<!-- This anchor is linked from HTTP 500 pages on tools.wmflabs.org -->Web logs ==
== {{anchor|Logs}}<!-- This anchor is linked from HTTP 500 pages on tools.wmflabs.org -->Web logs ==
Your tool's web logs are placed in the tool account's <code>$HOME/access.log</code> in common format. Please note that the web logs are anonymized in accordance with the Foundation’s privacy policy. Each user IP address will appear to be that of the local host, for example. In general, the privacy policy precludes the logging of personally identifiable information; special permission from Foundation legal counsel is required if such information is required.
Lighttpd error logs can be found in the tool account's <code>$HOME/error.log</code>; this includes the standard error of invoked scripts.


Error logs can be found in the tool account's <code>$HOME/error.log</code>; this includes the standard error of invoked scripts.
Beginning in October 2019, Lighttpd based webservices ''do not'' write access logs by default. Tool maintainers will be reminded of this by the following warning when starting a webservice:
<syntaxhighlight lang="bash">
******************************************************************************
Note that access.log is no longer enabled by default (see https://w.wiki/9go)
******************************************************************************
</syntaxhighlight>
 
If a tool has a need for access log data, it can be enabled by adding the following line in the tool account's <code>$HOME/.lighttpd.conf</code>:
 
<syntaxhighlight lang="lighttpd">
accesslog.filename = "{home}/access.log"
</syntaxhighlight>
 
Please note that the web logs are anonymized in accordance with the Wikimedia Foundation’s privacy policy by preventing the tool's webservice from seeing the IP address of the vistitor.


== Error pages ==
== Error pages ==

Revision as of 15:53, 15 October 2019

Lighttpd is the HTTP server used by both the lighttpd and lighttpd-plain types supported by webservice. These types are supported by both the Grid Engine and Kubernetes backends.

  • The document root is $HOME/public_html.
  • Error logs from the lighttpd process are stored in $HOME/error.log
  • PHP scripts are automatically run using a FastCGI helper process.
  • The lighttpd web server is configurable (including adding other FastCGI handlers). A $HOME/.lighttpd.conf file can be used to change the default configuration.
  • Everything runs as the tool user, regardless of file ownership.

The web server reads any configuration in $HOME/.lighttpd.conf, and merges it with the default configuration. Most tools will not need custom configuration.


Ambox notice.png Sometimes merge fails if an option is already set in the default configuration. When this happens, try using option += value instead of option = value.

Default configuration

This is the default (if you don't specify any other/additional settings in your tool's .lighttpd.conf)

See lighttpdwebservice.py in operations/software/tools/webservice for the canonical configuration.

Example configurations

FCGI Flask config

fastcgi.server += ( "/gerrit-patch-uploader" =>
    ((
        "socket" => "/tmp/patchuploader-fcgi.sock",
        "bin-path" => "/data/project/gerrit-patch-uploader/src/gerrit-patch-uploader/app.fcgi",
        "check-local" => "disable",
        "max-procs" => 1,
    ))
)

For Flask, the fcgi handler looks like this: https://github.com/valhallasw/gerrit-patch-uploader/blob/master/app.fcgi

URL rewrite

Documentation: ModRewrite

Note that rewrite rules always execute before redirect rules (regardless of their order in the config file).

A common rewrite scenario is a PHP application that uses a front controller script (often index.php) to decide how to process each request based on the path of the request. The url.rewrite-if-not-file directive can be used to do this while still letting lighttpd serve static files from $HOME/public_html normally:

url.rewrite-if-not-file += ( "(.*)" => "/YOUR_TOOL_NAME/index.php/$0" )

Alternately you can use url.rewrite-once to pick and choose which requests to rewrite:

url.rewrite-once += (
    ".*\.(js|css)" => "$0",
    "^/YOUR_TOOL_NAME(/.*)" => "/YOUR_TOOL_NAME/index.php$1"
)
url.rewrite-once += ( "/YOUR_TOOL_NAME/id/([0-9]+)" => "/YOUR_TOOL_NAME/index.php?id=$1",
                      "/YOUR_TOOL_NAME/link/([a-zA-Z]+)" => "/YOUR_TOOL_NAME/index.php?link=$1" )

The $0 matches the entire match from the left-hand side regular expression.

Header, mimetype, character encoding, error handler

# Allow Cross-Origin Resource Sharing (CORS)
setenv.add-response-header += ( "Access-Control-Allow-Origin" => "en.wikipedia.org",
                                 "Access-Control-Allow-Methods" => "POST, GET, OPTIONS" )

# Set cache-control directive for static files and resources
$HTTP["url"] =~ "\.(jpg|gif|png|css|js|txt|ico)$" {
	setenv.add-response-header += ( "Cache-Control" => "max-age=86400, public" )
}

mimetype.assign += (
    # Add custom mimetype
    ".bulk"  => "text/plain",
    # Avoid [[Mojibake]] in JavaScript files
    ".js"   => "application/javascript; charset=utf-8",
    # Default MIME type with UTF-8 character encoding
    ""      => "text/plain; charset=utf-8"
)

# Add custom error-404 handler
server.error-handler-404 += "/error-404.php"

Details: ModSetEnv  Mimetype-Assign   Error-Handler-404   HTTP access control (CORS)

Directory or file index

# Enable basic directory index
$HTTP["url"] =~ "^/?" {
	dir-listing.activate = "enable"
}

Deny access to hidden files

# Deny access to hidden files
$HTTP["url"] =~ "/\." {
	url.access-deny = ("")
}

Details: ModAccess

Custom index

# Enable index for specific directory
$HTTP["url"] =~ "^/download($|/)" {
	dir-listing.activate = "enable"
}

# Custom index file or custom directory generator
index-file.names += ("index.py")

Details: ModDirlisting

Request logging

Documentation: DebugVariables

Add the line:

# Enable request logging
debug.log-request-handling = "enable"

The debug output will be written to the error.log file.

Apache-like cgi-bin directory

Add the following stanza:

$HTTP["url"] =~ "^/your_tool/cgi-bin" {
	cgi.assign = ( "" => "" )
}

This does require that cgi-bin be under your public_html rather than alongside it.

To run CGI from any directory under your public_html only need this one line (w/out the $HTTP["url"] .. block)

cgi.assign += ( ".cgi" => "" )

The part to the left is the file name or extension ("" = any). The part to the right is the program which will run it ("" = any). Another example

cgi.assign += ( "script.sh" => "/bin/bash" )

Enable status and statistics

# modify <toolname> for your tool
# this will enable counters http://tools.wmflabs.org/<toolname>/server-status (resp: .../server-statistics)
server.modules += ("mod_status")
status.status-url = "/<toolname>/server-status"
status.statistics-url = "/<toolname>/server-statistics"

Details: ModStatus

Web logs

Lighttpd error logs can be found in the tool account's $HOME/error.log; this includes the standard error of invoked scripts.

Beginning in October 2019, Lighttpd based webservices do not write access logs by default. Tool maintainers will be reminded of this by the following warning when starting a webservice:

******************************************************************************
Note that access.log is no longer enabled by default (see https://w.wiki/9go)
******************************************************************************

If a tool has a need for access log data, it can be enabled by adding the following line in the tool account's $HOME/.lighttpd.conf:

accesslog.filename = "{home}/access.log"

Please note that the web logs are anonymized in accordance with the Wikimedia Foundation’s privacy policy by preventing the tool's webservice from seeing the IP address of the vistitor.

Error pages

The proxy provides its own error pages when your application returns HTTP/500, HTTP/502 or HTTP/503. This behavior is currently under review, and might change in the near future.

You can bypass the proxy error pages by passing an X-Wikimedia-Debug header.

Changing the document root

With symlinks

The easiest way to change the document root is with a symlink to $HOME/public_html. However, before this is done, the existing public_html directory needs to be deleted or moved. This is because ln -s $HOME/foo $HOME/public_html would make $HOME/public_html/foo if the $HOME/public_html directory exists. Deleting the directory is done with rm -rf $HOME/public_html to delete the directory and all of its contents, if you do not need anything in there, or with mv $HOME/public_html $HOME/oldpublic_html to move the directory to $HOME/oldpublic_html.

To make the symlink, ln -s $HOME/foo $HOME/public_html/ would make the contents of $HOME/foo available in $HOME/public_html. Replace $HOME/foo in the example with the directory you want lighttpd to serve.

With aliases

Note that you cannot add an alias URL for /toolname because this has already been defined and can't be overridden in the local conf file.

PHP

The lighttpd webservice type includes support for running PHP scripts from files with a .php in $HOME/public_html using a FastCGI helper process.

PHP ini settings can be changed for your tool by creating a $HOME/public_html/.user.ini configuration file. This can be useful for setting the default timezone with date.timezone. See the documentation at php.net for more details.