Making Clean and Reusable Salt States - Generic App Deployments Structure

README.md

Generic App Deployments

This is an outline of how to setup a generic app deployment using Salt Stack and all its features:

• Configure apps in the pillar
• Override git revisions with grains
• Setup box configurations with grains
• Resolve configurations with custom modules
• Generate states with jinja

pillar-appspecs.sls

appspecs:
  # This defines an application to deploy
  myapp:
    repo: myorg/myapp # Where to find the app's code
    rev: master
    
    # All the processes this app involves
    procs:
      service:
        # Configure how to launch it
        language: node
        main: service.js
        nprocs: 4

roots-_modules-generics.py

'''
A saltstack module to resolve the application specifications for this particular minion
The base appspecs are defined in pillar['appspecs']
The apps to deploy on this minion are defined via grains['apps']
For instance, grains['apps'] can be ['myapp','myotherapp'] or ['myapp@patch-1'] for changing revision number
'''

from os import path

def apps():
  '''
  Get a list of all applications to be configured in the generics system.
  Returns a list of (appname, appspec)
  '''
  specs = __pillar__.get('appspecs', {})
  apps = __grains__.get('apps', [])

  appspecs = (appspec(app, _appspecs=specs) for app in apps)
  return [(aspec['app'], aspec) for aspec in appspecs if appspec]

def procs(**filters):
  '''
  Get a list of all processes to be configured in the generics system.
  Returns a list of (appname, procname, appspec, procspec)
  Filters for processes that meet some filter.
  If a filter is None, just tests for existence in the procspec
  If a filter is not None, then it tests for equality in the procspec
  For example, nginx=None tests for nginx being in the procspec, but supervisord=True tests for procpsec['supervisord'] being True
  '''
  def gen():
    for app, aspec in apps():
      for proc in aspec['procs'].keys():
        pspec = _procspec(app, proc, aspec=aspec)

        if any(key not in pspec or (value != None and pspec[key] != value) for key, value in filters.items()):
          continue

        yield app, proc, aspec, pspec

  return list(gen())

def appspec(app, _appspecs=None):
  '''
  Get the appspec for an app
  '''
  _appspecs = _appspecs or __pillar__.get('appspecs', {})
  split = app.split('@')
  if len(split) > 1:
    app, rev = split # Here we set the revision number if an app has an '@' sign
  else:
    rev = None

  if app not in _appspecs:
    return None

  appspec = _appspecs[app]
  appspec['app'] = app
  appspec['rev'] = rev or appspec.get('rev', 'master')
  return appspec

def procspec(app, proc, _appspecs=None):
  '''
  Get the procspec for an process
  '''
  return _procspec(app, proc, appspec(app, _appspecs))

def _procspec(app, proc, aspec):
  '''
  Get the procspec for an process from an aspec
  '''
  return aspec.get('procs', {}).get(proc, {})

roots-apps-init.sls

# Download code from github
# And Run it using supervisord

include:
  - core.git

## Download code
{% for app, spec in salt['generics.apps']() %}

"[email protected]:{{spec['repo']}}":
  git.latest:
    - rev: {{spec['rev']}}
    - target: /src/{{app}}
    - force: yes
    - force_checkout: yes
    - always_fetch: yes
    - user: deploy # A custom user
    - identity: /home/deploy/.ssh/id_rsa # Gotta set this up yourself

{% endfor %}

## Run code using supervisord
include:
  - core.supervisor

{% for app, proc, aspec, pspec in salt['rcgenerics.procs'](supervisord=True) %}

# Splat the supervisord config on the file system
/etc/supervisor/conf.d/{{app}}-{{proc}}.conf:
  file.managed:
    - source: salt://apps/supervisord.conf.jinja
    - template: jinja
    - context:
        app: {{app}}
        proc: {{proc}}
    - mode: 755
    - user: deploy
    - group: deploy
    - require:
      - git: "[email protected]:{{aspec['repo']}}"

{% for pid in range(pspec.get('nprocs', 1)) %}

{{app}}-{{proc}}-start-{{pid}}:
  supervisord.running:
    - name: '{{app}}-{{proc}}:{{app}}-{{proc}}-p{{"%02d" % pid}}'
    - restart: true
    - update: true
    - watch:
      - file: '/etc/supervisor/conf.d/{{app}}-{{proc}}.conf'

{% endfor %}

{% endfor %}

roots-apps-supervisord.conf.jinja

# {% set pspec = salt['rcgenerics.procspec'](app, proc) %}

[program:{{app}}-{{proc}}]
directory = /src/{{app}}
redirect_stderr = true
stdout_logfile = /var/log/supervisor/{{app}}-{{proc}}-p%(process_num)02d.log
process_name = {{app}}-{{proc}}-p%(process_num)02d
numprocs = {{ pspec.get('nprocs', 1) if not dev else 1}}
stopasgroup = true
user = deploy

# {% if pspec['language'] == 'node' %}

command = node {{ pspec['main'] }}

# Put elif's here for all your deployment types
# {% endif %}

{% if pspec['language'] == 'node' %}
environment = HOME="/home/{{user}}",NODE_ENV="production"
{% else %}
environment = HOME="/home/{{user}}"
{% endif %}