autoscale: true
build-lists: true
theme: poster, 7
# [fit] *Deploying* PHP<br>applications<br>*with* Fabric
---
[.build-lists: false]
- What is Fabric and what do I use it for?
- How to write and organise Fabric scripts
- Task examples
---
[.build-lists: false]
- Senior Developer at Microserve
- Part-time freelance Developer & Sysadmin
- Drupal Bristol, PHPSW, DrupalCamp Bristol
- @opdavies
- oliverdavies.uk
^ Drupal (7 & 8), Symfony, Silex, Laravel, Sculpin
Not a Python Developer
---
## *What is* Fabric*?*
---
## What is Fabric?
*Fabric is a* Python (2.5-2.7) library and command-line tool for streamlining the use of SSH *for application deployment or systems administration tasks.*
---
## What is Fabric?
It provides a basic suite of operations for executing local or remote shell commands (normally or via sudo) and uploading/downloading files, as well as auxiliary functionality such as prompting the running user for input, or aborting execution.
---
## I use Fabric to...
- Simplify my build process
- Deploy code directly to different environments
- Act as an intermediate step
---
---
[.build-lists: false]
## Why Fabric?
- Powerful
- Flexible
- Easier to write than bash
^ - Can be used for different languages, frameworks
- Can be used for small, simple deployments or large, complicated ones
- Not very opinioned
---
## Installing Fabric
```bash
$ pip install fabric
# macOS
$ brew install fabric
# Debian, Ubuntu
$ apt-get install fabric
$ apt-get install python-fabric
```
---
## Writing your <br>first *fabfile*
---
```python
# fabfile.py
from fabric.api import env, run, cd, local
env.hosts = ['example.com']
# Do stuff...
```
^ Callables
---
```python
# fabfile.py
from fabric.api import *
env.hosts = ['example.com']
# Do stuff...
```
---
## Operations
- cd, lcd - *change directory*
- run, sudo, local - *run a command*
- get - *download files*
- put - *upload files*
[.footer: http://docs.fabfile.org/en/1.13/api/core/operations.html]
---
## Utils
- warn: *print warning message*
- abort: *abort execution, exit with error status*
- error: *call func with given error message*
- puts: *alias for print whose output is managed by Fabric's output controls*
[.footer: http://docs.fabfile.org/en/1.13/api/core/utils.html]
---
## File management
```python
from fabric.contrib.files import *
```
- exists - *check if path exists*
- contains - *check if file contains text/matches regex*
- sed - *run search and replace on a file*
- upload_template - *render and upload a template to remote host*
[.footer: http://docs.fabfile.org/en/1.13/api/contrib/files.html#fabric.contrib.files.append]
^ Allows for jinja2 templates
---
## Tasks
```python
def build():
with cd('/var/www/html'):
run('git pull')
run('composer install')
```
---
## Task arguments
```python, [.highlight: 1, 4-6]
def build(run_composer=True):
with cd('/var/www/html'):
run('git pull')
if run_composer:
run('composer install')
```
---
## Task arguments
```python, [.highlight: 1, 4-15]
def build(run_composer=True, env='prod', build_type):
with cd('/var/www/html'):
run('git pull')
if run_composer:
if env == 'prod':
run('composer install --no-dev')
else:
run('composer install')
if build_type == 'drupal':
...
elif build_type == 'symfony':
...
elif build_type == 'sculpin':
...
```
---
## Calling other tasks
```python, [.highlight: 4-15]
@task
def build():
with cd('/var/www/html'):
build()
post_install()
def build():
run('git pull')
run('composer install')
def post_install():
with prefix('drush'):
run('updatedb -y')
run('entity-updates -y')
run('cache-rebuild')
```
^ Better organised code
Not everything in one long
Easier to read and comprehend
Single responsibilty principle
---
## Running Tasks
```bash
fab --list
fab <task>
fab <task>:build_number=$BUILD_ID,build_type=drupal
```
^ fabfile.py in the current directory is found automatically.
---
```
[production] Executing task 'main'
[production] run: git pull
[production] out: Already up-to-date.
[production] out:
[production] run: composer install
...
[production] out: Generating autoload files
[production] out:
Done.
Disconnecting from production... done.
```
---
## Downsides
- Running build tasks on production
---
[.build-lists: false]
## *Not* Building on Prod
1. Build locally and deploy.
---
## Local tasks
```python
# Runs remotely.
from fabric.api import run
run('git pull')
run('composer install')
# Runs locally.
from fabric.api import local
local('git pull')
local('composer install')
```
---
## Local tasks
```python
# Remote.
from fabric.api import cd
with cd('themes/custom/drupalbristol'):
...
# Runs locally.
from fabric.api import lcd
with lcd('themes/custom/drupalbristol'):
...
```
---
## rsync
```python, [.highlight: 1, 5-11]
from fabric.contrib.project import rsync_project
...
def deploy():
rsync_project(
local_dir='./',
remote_dir='/var/www/html'
default_opts='-vzcrSLh',
exclude=('.git', 'node_modules/', '.sass-cache/')
)
```
---
```
[production] Executing task 'main'
[localhost] local: git pull
Current branch master is up to date.
[localhost] local: composer install
Loading composer repositories with package information
Installing dependencies (including require-dev) from lock file
Nothing to install or update
Generating autoload files
Done.
```
^ - The risky steps have been run separate to the live code.
- Any issues will not affect the live site.
---
[.build-lists: false]
## *Not* Building on Prod
1. ~~Build locally and deploy.~~
1. Build in a separate directory and switch after build.
^ Capistrano
---
## Deploying into a *different directory*
```python
from fabric.api import *
from time import time
project_dir = '/var/www/html'
next_release = "%(time).0f" % { 'time': time() } # timestamp
def init():
if not exists(project_dir):
run('mkdir -p %s/backups' % project_dir)
run('mkdir -p %s/shared' % project_dir)
run('mkdir -p %s/releases' % project_dir)
```
---
## Deploying into a *different directory*
```python
current_release = '%s/%s' % (releases_dir, next_release)
run('git clone %s %s' % (git_repo, current_release))
def build():
with cd(current_release):
pre_tasks()
build()
post_tasks()
```
^ - Clone the repository into a different directory
- Run any "risky" tasks away from the production code
---
## Deploying into a *different directory*
```python
def pre_build(build_number):
with cd('current'):
print '==> Dumping the DB (just in case)...'
backup_database()
def backup_database():
cd('drush sql-dump --gzip > ../backups/%s.sql.gz' % build_number)
```
---
## Deploying into a *different directory*
```python
def update_symlinks():
run('ln -nfs %s/releases/%s %s/current'
% (project_dir, next_release, project_dir))
# /var/www/html/current
```
---
```
[production] Executing task 'main'
[production] run: git clone https://github.com/opdavies/oliverdavies.uk.git
/var/www/html/releases/1505865600
===> Installing Composer dependencies...
[production] run: composer install --no-dev
===> Update the symlink to the new release...
[production] run: ln -nfs /var/www/html/releases/1505865600
/var/www/html/current
Done.
```
---
```bash
# /var/www/html
shared
releases/1502323200
releases/1505692800
releases/1505696400
releases/1505865600
current -> releases/1505865600 # symlink
```
---
## Positives
- Errors happen away from production
## Downsides
- Lots of release directories
---
## Removing old builds
```python
def main(builds_to_keep=3):
with cd('%s/releases' % project_dir):
run("ls -1tr | head -n -%d | xargs -d '\\n' rm -fr"
% builds_to_keep)
```
^ - Find directory names
- 1tr not ltr
- Remove the directories
- Additional tasks, removing DB etc
---
## Is the site still running?
---
## Checking for failures
```python
run(command).failed:
# Fail
run(command).return_code == 0:
# Pass
run(command).return_code == 1:
# Fail
```
^ Works for local and remote.
---
```python
def post_tasks():
print '===> Checking the site is alive.'
if run('drush status | egrep "Connected|Successful"').failed:
# Revert back to previous build.
```
---
```bash, [.highlight 3]
$ drush status
Drupal version : 8.3.7
Site URI : http://default
Database driver : mysql
Database hostname : db
Database username : user
Database name : default
Database : Connected
Drupal bootstrap : Successful
Drupal user :
Default theme : bartik
Administration theme : seven
PHP configuration : /etc/php5/cli/php.ini
...
```
^ "Database" to "PHP configuration" missing if cannot connect.
---
## Does the code still merge cleanly?
^ Pre-task
---
```python
def check_for_merge_conflicts(target_branch):
with settings(warn_only=True):
print('===> Ensuring that this can be merged into the main branch.')
if local('git fetch && git merge --no-ff origin/%s' % target_branch).failed:
abort('Cannot merge into target branch.')
```
---
## Making fabric smarter
---
## Conditional variables
```python
drupal_version = None
if exists('composer.json') and exists('core'):
drupal_version = 8
else:
drupal_version = 7
```
---
## Conditional tasks
```python
if exists('composer.json'):
run('composer install')
with cd('themes/custom/example'):
if exists('package.json') and not exists('node_modules'):
run('yarn --pure-lockfile')
if exists('gulpfile.js'):
run('node_modules/.bin/gulp --production')
elif exists('gruntfile.js'):
run('node_modules/.bin/grunt build')
```
---
## Project settings file
```yml
# app.yml
drupal:
version: 8
root: web
config:
import: yes
name: sync
cmi_tools: no
theme:
path: 'themes/custom/drupalbristol'
build:
npm: no
type: gulp
yarn: yes
composer:
install: true
```
---
## Project settings file
```python, [.highlight 3]
# fabfile.py
from fabric.api import *
import yaml
with open('app.yml', 'r') as file:
config = yaml.load(file.read())
```
---
## Project settings file
```python
# fabfile.py
if config['composer']['install'] == True:
local('composer install')
```
---
## Project settings file
```python
# fabfile.py
if build_type == 'drupal':
drupal = config['drupal']
with cd(drupal['root']):
if drupal['version'] == 8:
if drupal['config']['import'] == True:
if drupal['config']['cmi_tools']:
run('drush cim -y %s' % drupal['config']['import']['name'])
else:
run('drush cimy -y %s' % drupal['config']['import']['name'])
if drupal['version'] == 7:
...
```
^ - Less hard-coded values
- More flexible
- No need to use different files for different versions or frameworks
- No forked fabfiles per project or lots of conditionals based on the project
---
## Project settings file
```python
theme = config['theme']
with cd(theme['path']):
if theme['build']['gulp'] == True:
if env == 'prod':
run('node_modules/.bin/gulp --production')
else:
run('node_modules/.bin/gulp')
```
---
## Project settings file v2
```yml
# app.yml
commands:
build: |
cd web/themes/custom/drupalbristol
yarn --pure-lockfile
node_modules/.bin/gulp --production
deploy: |
cd web
drush cache-rebuild -y
```
---
## Project settings file v2
```python
# fabfile.py
for hook in config['commands'].get('build', '').split("\n"):
run(hook)
...
for hook in config['commands'].get('deploy', '').split("\n"):
run(hook)
```
---
## Other things
- Run Drush/console/artisan commands
- Verify file permissions
- Restart services
- Anything you can do on the command line...
---
[.build-lists: false]
## Fabric has...
- Simplified my build process
- Made my build process more flexible
- Made my build process more robust
---
[.build-lists: false]
- https://www.oliverdavies.uk/talks/deploying-php-fabric
- http://fabfile.org
- https://github.com/opdavies/fabric-example-sculpin
- https://github.com/opdavies/fabric-example-drupal
- https://deploy.serversforhackers.com (~~$129~~ $79)
---
## *joind.in/talk/*4e35d
---
## @opdavies
## *oliverdavies.uk*