"""
Author: Jharrod LaFon
See also: https://github.com/jlafon/ansible-profile
"""

import time


class CallbackModule(object):
    """
    A plugin for timing tasks
    """
    def __init__(self):
        self.stats = {}
        self.current = None

    def playbook_on_task_start(self, name, is_conditional):
        """
        Logs the start of each task
        """
        if self.current is not None:
            # Record the running time of the last executed task
            self.stats[self.current] = time.time() - self.stats[self.current]

        # Record the start time of the current task
        self.current = name
        self.stats[self.current] = time.time()

    def playbook_on_stats(self, stats):
        """
        Prints the timings
        """
        # Record the timing of the very last task
        if self.current is not None:
            self.stats[self.current] = time.time() - self.stats[self.current]

        # Sort the tasks by their running time
        results = sorted(
            self.stats.items(),
            key=lambda value: value[1],
            reverse=True,
        )

        # Just keep the top 10
        results = results[:10]

        print

        # Print the timings
        for name, elapsed in results:
            print(
                "{0:-<70}{1:->9}".format(
                    '{0} '.format(name),
                    ' {0:.02f}s'.format(elapsed),
                )
            )

        print

Add Ansible callback plugin to profile tasks
Add Ansible callback plugin to profile tasks

In order to try and speed up provisioning, this changeset adds a plugin
that gives you the per task duration breakdown of a playbook. From here,
we can identify the outliers and spend a little time making them faster.

Example tiler output:

```
PLAY RECAP ********************************************************************

azavea.mapnik | Install Mapnik ----------------------------------------- 35.60s
azavea.nginx | Configure the Nginx PPA --------------------------------- 22.61s
Update APT cache ------------------------------------------------------- 11.47s
azavea.beaver | Install Beaver ------------------------------------------ 9.48s
azavea.nodejs | Upgrade NPM --------------------------------------------- 8.94s
azavea.collectd | Install Collectd -------------------------------------- 8.70s
azavea.nodejs | Download Node.js ---------------------------------------- 5.91s
model-my-watershed.tiler | Install tiler javascript dependencies -------- 4.55s
azavea.nginx | Install Nginx -------------------------------------------- 3.97s
model-my-watershed.tiler | Install canvas rendering dependencies -------- 3.95s

tiler                      : ok=62   changed=56   unreachable=0    failed=0
```
