Liip Monitor Bundle

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Type: symfony-bundle

2.1.3 2015-10-24 15:31 UTC


Build Status Scrutinizer Code Quality

This bundle provides a way to run a series of application related health checks. Health checks in the scope of this bundle go beyond simple actions like performing a ping to a server to see if it's alive. For example a Memcache server can be alive and not displaying any errors in your Nagios but you might not be able to access it from your PHP application. Each health check should then implement some application logic that you want to make sure always works. Another usage can be testing for specific requirements, like availability of PHP extensions.

Another design goal of the bundle was to be able to perform the checks using the same configuration and environment that your application is using. In that way you can make sure that if the health check runs successfully then your app should work too.

So each health check will be a class that will implement the CheckInterface::check method which must return a CheckResult object. What happens inside that method is up to the check developer.

Health checks are defined as Symfony services and they have to be tagged as liip_monitor.check in order to be picked up by the health check runner. This gives a lot of flexibility to application and bundle developers when they want to add their own checks.

Checks are run via the command line using a Symfony command or via a REST api that delivers the results in JSON format.

Here's the web interface:

Web Interface


Install with composer:

$ composer require liip/monitor-bundle

Then register the bundle in the AppKernel.php file:

public function registerBundles()
    $bundles = array(
        // ...
        new Liip\MonitorBundle\LiipMonitorBundle(),
        // ...

    return $bundles;

If you want to enable the REST API provided by the bundle then add the following to your routing.yml:

    resource: "@LiipMonitorBundle/Resources/config/routing.xml"
    prefix: /monitor/health

Then, enable the controller in your configuration:

    enable_controller: true

And finally don't forget to install the bundle assets into your web root:

$ ./app/console assets:install web --symlink --relative

Enabling built-in health checks

To enable built-in health checks, add them to your config.yml

        php_extensions: [apc, xdebug]

Adding Health Checks

Once you implemented the class then it's time to register the check service with our service container:

        class: Acme\HelloBundle\Check\PhpExtensionsCheck
            - [ xhprof, apc, memcache ]
            - { name: liip_monitor.check, alias: php_extensions }

The important bit there is to remember to tag your services with the liip_monitor.check tag. By doing that the check runner will be able to find your checks. Keep in mind that checks can reside either in your bundles or in your app specific code. The location doesn't matter as long as the service is properly tagged. The alias is optional and will then simply define the id used when running health checks individually, otherwise the full service id must be used in this case.

Available Built-in Health Checks

See "Full Default Config" below for a list of all built-in checks and their configuration.

Running Checks

There are two ways of running the health checks: by using the CLI or by using the REST API provided by the bundle. Let's see what commands we have available for the CLI:

List Checks

$ ./app/console monitor:list


Run All the Checks

$ ./app/console monitor:health

Jackrabbit Health Check: OK
Redis Health Check: OK
Memcache Health Check: KO - No configuration set for session.save_path
PHP Extensions Health Check: OK

Run Individual Checks

To run an individual check you need to provide the check id to the health command:

$ ./app/console monitor:health monitor.check.php_extensions

PHP Extensions Health Check: OK

Run health checks as composer post-install/update scripts

To run health checks as a composer post-install or post-update script, simply add the Liip\\MonitorBundle\\Composer\\ScriptHandler::checkHealth ScriptHandler to the post-install-cmd / post-update-cmd command sections of your composer.json:

"scripts": {
    "post-install-cmd": [
    "post-update-cmd": [

Adding Additional Reporters

There are two default reporters: ArrayReporter for the REST API and ConsoleReporter for the CLI command. You can add additional reporters to be used by either of these.

First, define an additional reporter service and tag it with liip_monitor.additional_reporter:

    class: My\Reporter
        - { name: liip_monitor.additional_reporter, alias: my_reporter }

To run additional reporters with the CLI, add --reporter=... options for each one:

$ ./app/console monitor:health --reporter=my_reporter

To run this reporter with the REST API, add a reporters query parameter:


You can list available reporters with:

$ ./app/console monitor:list --reporters

Full Default Config

    enable_controller:    false
        enabled:              false
        recipient:            ~ # Required
        sender:               ~ # Required
        subject:              ~ # Required
        send_on_warning:      true
        # Validate that a named extension or a collection of extensions is available
        php_extensions:       [] # Example: [redis, mysqli]

        # Pairs of a PHP setting and an expected value
        php_flags:            # Example: session.use_only_cookies: false

            # Prototype
            setting:              ~

        # Pairs of a version and a comparison operator
        php_version:          # Example: 5.4.15: >=

            # Prototype
            version:              ~

        # Process name/pid or an array of process names/pids
        process_running:      ~ # Example: [apache, foo]

        # Validate that a given path (or a collection of paths) is a dir and is readable
        readable_directory:   [] # Example: ["%kernel.cache_dir%"]

        # Validate that a given path (or a collection of paths) is a dir and is writable
        writable_directory:   [] # Example: ['%kernel.cache_dir%']

        # Validate that a class or a collection of classes is available
        class_exists:         [] # Example: ["Lua", "My\Fancy\Class"]

        # Benchmark CPU performance and return failure if it is below the given ratio
        cpu_performance:      ~ # Example: 1.0 # This is the power of an EC2 micro instance

        # Checks to see if the disk usage is below warning/critical percent thresholds
            warning:              70
            critical:             90
            path:                 '%kernel.cache_dir%'

        # Checks Symfony2 requirements file
            file:                 '%kernel.root_dir%/SymfonyRequirements.php'

        # Checks to see if the OpCache memory usage is below warning/critical thresholds
            warning:              70
            critical:             90

        # Checks to see if the APC memory usage is below warning/critical thresholds
            warning:              70
            critical:             90

        # Checks to see if the APC fragmentation is below warning/critical thresholds
            warning:              70
            critical:             90

        # Connection name or an array of connection names
        doctrine_dbal:        null # Example: [default, crm]

        # Check if MemCache extension is loaded and given server is reachable

            # Prototype
                host:                 localhost
                port:                 11211

        # Validate that a Redis service is running

            # Prototype
                host:                 localhost
                port:                 6379

        # Attempt connection to given HTTP host and (optionally) check status code and page content

            # Prototype
                host:                 localhost
                port:                 80
                path:                 /
                status_code:          200
                content:              null

        # Attempt connection using Guzzle to given HTTP host and (optionally) check status code and page content

            # Prototype
                url:                  localhost
                headers:              []
                options:              []
                status_code:          200
                content:              null
                method:               GET
                body:                 null

        # Validate that a RabbitMQ service is running

            # Prototype
                host:                 localhost
                port:                 5672
                user:                 guest
                password:             guest
                vhost:                /

        # Checks the version of this app against the latest stable release
        symfony_version:      ~

        # Checks if error pages have been customized for given error codes
            error_codes:          [] # Required
            path:                 '%kernel.root_dir%'
            controller:           '%twig.exception_listener.controller%'

        # Checks installed composer dependencies against the SensioLabs Security Advisory database
            lock_file:            '%kernel.root_dir%/../composer.lock'

        # Validate that a stream wrapper or collection of stream wrappers exists
        stream_wrapper_exists:  [] # Example: ['zlib', 'bzip2', 'zip']

        # Find and validate INI files
        file_ini:             [] # Example: ['path/to/my.ini']

        # Find and validate JSON files
        file_json:            [] # Example: ['path/to/my.json']

        # Find and validate XML files
        file_xml:             [] # Example: ['path/to/my.xml']

        # Find and validate YAML files
        file_yaml:            [] # Example: ['path/to/my.yml']

        # Checks that fail/warn when given expression is false (expressions are evaluated with symfony/expression-language)

            # Example:
                label:               OPcache
                warning_expression:  ini('opcache.revalidate_freq') > 0
                critical_expression: ini('opcache.enable')
                warning_message:     OPcache not optimized for production
                critical_message:    OPcache not enabled

            # Prototype
                label:                ~ # Required
                warning_expression:   null # Example: ini('apc.stat') == 0
                critical_expression:  null # Example: ini('short_open_tag') == 1
                warning_message:      null
                critical_message:     null


For documentation on the REST API see: Don't forget to add the bundle routes in your routing.xml file.

Nagios integration

You can find a simple Nagios check written in Perl and Python in the Resources/scripts directory.

Perl Version

This is dependent on perl modules available on CPAN Getopt::Std, WWW::Mechanize, and JSON

Copy the script into your scripts directory in Nagios and create a command like this:

define command{
        command_name    check_symfony_health
        command_line    $USER1$/ -H $HOSTNAME$

Running the command with the Hostname flag (-H) will check "http://$HOSTNAME$/monitor/health/run". You can also use the Address flag (-A) to check a specified URL:

command_line    $USER1$/ -A

The plugin can be used with Authentication, Using the Username (-u) and Password (-p) flags:

command_line    $USER1$/check_symfony2.p1 -H $HOSTNAME$ -u username -p password

You can also specify the Warning (-w) and Critical (-c) levels for the check using the standard flags

command_line    $USER1$/ -H $HOSTNAME$ -w 1 -c 2

Any flags can be combined except -A and -H. THe -u and -p flags should always be used together.

Python Version

The Python version depends on the nagiosplugin library < 1.0.0.

Copy the script into your scripts directory in Nagios and create a command like this:

define command{
        command_name    check_symfony_health
        command_line    $USER1$/ -w 0  -c 0 -u https://$HOSTNAME$

To use the plugin with HTTP basic authentication, change the command to:

command_line    $USER1$/ -w 0  -c 0 -u https://$HOSTNAME$ -a username:password

Connecting Check to Host in Nagios

Add a service:

define service{
 hostgroup_name         Symfony2
 service_description    Symfony2 health check
 check_command          check_symfony_health
 use                    generic-service

And create a host attached to the Symfony2 hostgroup:

define host{
    use              web-host
    hostgroups       Symfony2

And place your host within the Symfony2 hostgroup.