datadog_agent.py

import os
import socket

from charmhelpers.core.templating import render

from charmhelpers.core.host import (
    service_restart,
    service_running,
    service_start,
)

from charms.reactive import (
    when,
    when_not,
    set_state
)

from charmhelpers.core.hookenv import (
    config,
    status_set,
)

import charms.apt


DD_AGENT_DIR = os.path.join('/', 'etc', 'dd-agent')


@when_not('apt.installed.datadog-agent')
def install_dd_agent():
    """Set the datadog-agent pkg from apt
    """
    charms.apt.queue_install(['datadog-agent'])
    charms.apt.install_queued()
    set_state('datadog.agent.installed')


@when('apt.installed.datadog-agent')
@when_not('datadog.agent.configured')
def write_dd_agent_config():
    """Write out the datadog-agent config
    """

    dd_example_conf = os.path.join(DD_AGENT_DIR, 'datadog.conf.example')
    dd_conf = os.path.join(DD_AGENT_DIR, 'datadog.conf')

    # Check for and remove conf
    if os.path.exists(dd_conf):
        os.remove(dd_conf)
    # Check for and remove example conf
    if os.path.exists(dd_example_conf):
        os.remove(dd_example_conf)

    # Collect vars for config template
    dd_agent_ctxt = {'hostname': socket.gethostname(),
                     'api_key': config('api-key')}
    # Render datadog.conf
    render(source='datadog.conf.tmpl', target=dd_conf, owner='dd-agent',
           group='root', perms=0o640, context=dd_agent_ctxt)
    # Set datadog.agent.configured state
    set_state('datadog.agent.configured')


@when('datadog.agent.configured')
@when_not('datadog.agent.available')
def start_restart_dd_agent():
    """Start or restart datadog agent
    """

    if config('no-start'):
        # If the no-start config is true, we are done
        status_set('active', 'Datadog agent installed')
    else:
        # Ensure datadog agent is running
        if service_running('datadog-agent'):
            service_restart('datadog-agent')
        else:
            service_start('datadog-agent')
        # Set status
        status_set('active', 'Datadog agent installed and running')
    # Set datadog available state
    set_state('datadog.agent.available')