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https://github.com/jgraichen/salt-tower

A salt external pillar for replacing salt pillars
https://github.com/jgraichen/salt-tower

pillar salt salt-master salt-tower yaml yamlet

Last synced: about 2 months ago
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A salt external pillar for replacing salt pillars

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README 

        
Salt Tower (Logo)




# Salt Tower — A Flexible External Pillar Module



[![GitHub Workflow Status](https://github.com/jgraichen/salt-tower/actions/workflows/test.yml/badge.svg)](https://github.com/jgraichen/salt-tower/actions/workflows/test.yml)



Salt Tower is an advanced and flexible `ext_pillar` that gives access to pillar values while processing and merging them, can render all usual salt file formats and include private and binary files for a minion.



Salt Tower is inspired by [pillarstack](https://github.com/bbinet/pillarstack) for merging pillar files and giving access to them. It also has a [top file](#top-file) like salt itself and utilizes salt renderers to supports all formats such as YAML, Jinja, Python and any combination. Supercharged [renderers for plain text and YAML](#yamlet-renderer) are included too.



Each tower data file is passed the current processed pillars. They can therefore access previously defined values. Data files can include other files that are all merged together.



Salt Tower is designed to completely replace the usual pillar repository or can be utilized beside salts original pillar that e.g. can bootstrap a salt master with Salt Tower.



## Questions or Need Help?



See [examples](examples/). They each have their own README further explaining the given example.



There is a [group](https://groups.google.com/d/forum/salt-tower) and [mailing list](mailto:[email protected]). You can join the group [here](https://groups.google.com/d/forum/salt-tower/join) or by sending a [subscribe-email](mailto:[email protected]).



Feel free to ask for help, discuss solutions or ideas there. Otherwise, you can open an [issue](https://github.com/jgraichen/salt-tower/issues/new).



## Installation



### GitFS



You can include this repository as a gitfs root and synchronize the extensions on the master:



```yaml

gitfs_remotes:

- https://github.com/jgraichen/salt-tower.git:

  - base: v1.12.0

```



Sync all modules:



```session

$ salt-run saltutil.sync_all

pillar:

    - pillar.tower

renderers:

    - renderers.filter

    - renderers.text

    - renderers.yamlet

```



Please note that *everything* in this repository would be merged with your other roots.



### pip



```session

pip install salt-tower

```



### Manual installation



Install the extension files from the `salt_tower/{pillar,renderers}` directories into the `extension_modules` directory configured in salt.



## Configuration



Salt Tower is configured as an `ext_pillar`:



```yaml

ext_pillar:

  - tower: /path/to/tower.sls

```



### Top File



The `tower.sls` file is similar to the usual `top.sls` with some important differences.



#### Ordered matchers



Pillar top items are ordered and processed in order of appearance. You can therefore define identical matchers multiple times.



```yaml

# tower.sls

base:

  - '*':

      - first



  - '*':

      - second

```



#### Common includes



You do not need to define a matcher at all, the files will be included for all minions. Furthermore, you also can use globs to match multiple files, e.g. include all files from `common/`.



```yaml

base:

  - common/*

```



#### Grains



The top file itself is rendered using the default renderer (`yaml|jinja`). Therefore, you can use e.g. `grains` to include specific files.



```yaml

base:

  - common/*

  - dist/{{ grains['oscodename'] }}

```



#### Embedded data



You can directly include pillar data into the top file simply be defining a `dict` item.



```yaml

base:

  - '*.a.example.org':

      - site:

          id: a

          name: A Site

```



#### Iterative pillar processing



All matchers are compound matchers by default. As items are processes in order of appearance, later items can patch on previously defined pillar values. The above example includes `application.sls` for any minion matching `*.a.example.org` simply because it defines a `site` pillar value.



```yaml

base:

  - '*.a.example.org':

      - site: {id: a, name: A Site}



  - 'I@site:*':

      - applications

```



#### Late-bound variable replacement



File includes are preprocessed by a string formatter to late-bind pillar values.



```yaml

base:

  - '*.a.example.org':

      - site: {id: a, env: production}



  - '*.a-staging.example.org':

      - site: {id: a, env: staging}



  - 'I@site:*':

      - site/default

      - site/{site.id}

      - site/{site.id}/{site.env}/*

```



In the above example a minion `node0.a-staging.example.org` will include the following files:



```text

site/default

site/a

site/a/staging/*

```



#### File lookup



File names will be matches to files and directories, e.g. when including `path/to/file` the first existing match will be used:



```text

path/to/file

path/to/file.sls

path/to/file/init.sls

```



### Tower Data File



A data file is processed like a usual pillar file. Rendering uses salts template engines therefore all usual features should be available.



The injected `pillar` objects can be used to access previously defined values. The additional `.get` method allows to traverse the pillar tree.



```yaml

application:

  title: Site of {{ pillar.get('tenant:name') }}

```



**Note:** Using `salt['pillar.get']()` will *not* work.



Tower data files can be [any supported template format](https://docs.saltstack.com/en/latest/ref/renderers/) including python files:



```py

#!py



def run():

    ret = {'databases': []}



    for app in __pillar__['application']:

        ret['databases'].append({

            'name': '{0}-{1}'.format(app['name'], app['env'])

        })



    return ret

```



#### Includes



Pillar data files can include other pillar files similar to how states can be included:



```yaml

include:

  - another/pillar



data: more

```



Included files cannot be used in the pillar data file template itself but are merged in the pillar before the new pillar data. Includes can be relative to the current file by prefixing a dot:



```yaml

include:

  - file/from/pillar/root.sls

  - ./adjacent_file.sls

  - ../parent_file.sls

```



### Yamlet renderer



The Yamlet renderer is an improved YAML renderer that supports loading other files and rendering templates:



```yaml

ssh_private_key: !read id_rsa

ssh_public_key: !read id_rsa.pub

```



This reads a file from the pillar directory in plain text or binary and embeds it into the pillar to e.g. ease shipping private file blobs to minions.



Using the `!include` tag files can be pushed through salts rendering pipeline on the server:



```yaml

nginx:

  sites:

    my-app: !include ../files/site.conf

```



```jinja

#!jinja | text strip

server {

  listen {{ pillar.get('my-app:ip') }}:80;

  root /var/www/my-app;

}

```



The pillar will return the following:



```yaml

nginx:

  sites:

    my-app: |

      server {

        listen 127.0.0.1:80;

        root /var/www/my-app;

      }

```



This can greatly simplify states as they only need to drop pillar values into config files and restart services:



```sls

nginx:

  pkg.installed: []

  service.running: []



{% for name in pillar.get('nginx:sites', {}) %}

/etc/nginx/sites-enabled/{{ name }}:

  file.managed:

    - contents_pillar: nginx:sites:{{ name }}

    - makedirs: True

    - watch_in:

      - service: nginx

{% endfor %}

```



The yamlet renderer `!include` macro does accept context variables too:



```yaml

nginx:

  sites:

    my-app: !include

      source: ../files/site.conf

      context:

        listen_ip: 127.0.0.1

```



```jinja

#!jinja | text strip

server {

  listen {{ listen_ip }}:80;

  root /var/www/my-app;

}

```



### Text renderer



The text renderer (used above) renders a file as plain text. It stripes the shebang and can optionally strip whitespace from the beginning and end.



```text

#!text strip



Hello World

```



This will return:



```text

Hello World

```



The text renderer is mostly used for embedding rendered configuration files into a Yamlet file.



### Filter renderer



The filter renderer returns only a subset of data that matches a given grain or pillar key value:



```yaml

#!yamlet | filter grain=os_family default='Unknown OS'



Debian:

  package_source: apt



RedHat:

  package_source: rpm



Unknown OS:

  package_source: unknown

```



When this file is rendered, only the data from the matching top level key is returned. The renderer supports glob matches and uses the minion ID by default:



```yaml

#!yamlet | filter



minion-1:

  monitoring:

    type: ping

    address: 10.0.0.1



webserver-*:

  monitoring:

    type: http

    address: http://example.org

```



### Advanced usage (very dangerous)



The pillar object passed to the python template engine is the actual mutable dict reference used to process and merge the data. It is possible to modify this dict e.g. in a python template without returning anything:



```python

#!py



import copy



def run():

    databases = __pillar__['databases']

    default = databases.pop('default') # Deletes from actual pillar



    for name, config in databases.items():

        databases[name] = dict(default, **config)



    return {}

```



*Note 1:* Do not return `None`. Otherwise, [Salt will render the template twice](https://github.com/saltstack/salt/blame/v2019.2.0/salt/template.py#L108) and all side effects will be applied twice.



*Note 2:* The `__pillar__` object in Python templates is different to other template engines. It is a dict and does not allow traversing using `get`.



```py

#!py



def run():

    return {

        'wrong': __pilar__.get('tenant:name'),

        'python': __pillar__['tenant']['name'],

        'alternative': tower.get('tenant:name')

    }

```



The above example demonstrates different usages. The first example will only work if the pillar contains an actual `tenant:name` top-level key. The second example is idiomatic-python but will raise an error if the keys do not exist. The third example uses the additional `tower` helper module to traverse the pillar data.



The `tower` pillar object is available in all rendering engines and can be used for low-level interaction with the ext_pillar engine. Some available functions are:



#### tower.get(key, default=None, require=False)



Get a pillar value by given traverse path:



```python

tower.get('my:pillar:key')

```



If `require=True` is set, `default` will be ignored and a KeyError will be raised if the pillar key is not found.



#### tower.update(dict)



Merges given dictionary into the pillar data.



```python

tower.update({'my': {'pillar': 'data'}})



assert tower.get('my:pillar') == 'data'

```



#### tower.merge(tgt, *objects)



Merges given dictionaries or lists into the first one.



Note: The first given dictionary or list is *mutated* and returned.



```python

tgt = {}



ret = tower.merge(tgt, {'a': 1})



assert ret is tgt

assert tgt['a'] == 1

```



#### tower.format(obj, *args, **kwargs)



Performs recursive late-bind string formatting using tower pillar and given arguments ad keywords for resolving. Uses `string.Formatter` internally.



```python

tower.update({

    'database': {

        'password': 'secret'

    }

})



ret = tower.format('postgres://user@{database.password}/db')



assert ret == 'postgres://user@secret/db'

```



Format accept dictionaries and list as well and can therefore be used to format full or partial pillar data, this can be used to e.g. format defaults with extra variables:



```python

#!py



def run():

    returns = {}

    defaults = __pillar__['default_app_config']

    # e.g. {

    #        'database': 'sqlite:///opt/{name}.sqlite'

    #        'listen': '0.0.0.0:{app.port}'

    # }



    for name, conf in __pillar__['applications'].items():

        # Merge defaults with conf into new dictionary

        conf = tower.merge({}, defaults, conf)



        # Format late-bind defaults with application config

        conf = tower.format(conf, name=name, app=conf)



        returns[name] = conf



    return {'applications': returns}

```