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Escaping of References and Inventory Queries

Reference and inventory queries can be escaped to produce literal strings, for example:

parameters:
  colour: Blue
  unescaped: The colour is ${colour}
  escaped: The colour is \${colour}
  double_escaped: The colour is \\${colour}

This would produce:

parameters:
  colour: Blue
  unescaped: The colour is Blue
  escaped: The colour is ${colour}
  double_escaped: The colour is \Blue

Ignore class not found

At some cases (bootstrapping, development) it can be convenient to ignore some missing classes. To control the feature there are two options available:

ignore_class_notfound: False
ignore_class_notfound_regexp: ['.*']

If you set regexp pattern to service.* all missing classes starting 'service.' will be logged with warning, but will not fail to return rendered reclass. Assuming all parameter interpolation passes.

Merging Referenced Lists and Dictionaries

Referenced lists or dicts can now be merged:

# nodes/test.yml
classes:
  - test1
  - test2
parameters:
  one:
    a: 1
    b: 2
  two:
    c: 3
    d: 4
  three:
    e: 5

# classes/test1.yml
parameters:
  three: ${one}

# classes/test2.yml
parameters:
  three: ${two}

running reclass.py --nodeinfo node1 then gives:

parameters:
  one:
    a: 1
    b: 2
  three:
    a: 1
    b: 2
    c: 3
    d: 4
    e: 5
  two:
    c: 3
    d: 4

This first sets the parameter three to the value of parameter one (class test1) then merges parameter two into parameter three (class test2) and finally merges the parameter three definition given in the node definition into the final value.

Allow override list and dicts by empty entity,None instead of merge

With settings:

allow_none_override: True       # default True

# note dict,list over None is allowed and not configurable

Referenced lists or dicts can now be overriden by None or empty type of dict, list:

# nodes/test.yml
parameters:
  one:
    a: 1
    b: 2
  two: {}
  three: None

# classes/test1.yml
parameters:
  one: ${two}

# classes/test2.yml
parameters:
  three: ${one}

Constant Parameters

Parameters can be labeled as constant by using the prefix =

parameters:
  =one: 1

If in the normal parameter merging a constant parameter would be changed then depending on the setting of strict_constant_parameters either an exception is raised (strict_constant_parameters true) or the parameter is left unchanged and no notification or error is given (strict_constant_parameters false)

For example with:

# nodes/node1.yml
classes:
- first
- second

# classes/first.yml
parameters:
  =one: 1

# classes/second.yml
parameters:
  one: 2

reclass.py --nodeinfo node1 then gives an ''Attempt to change constant value'' error if strict_constant_parameters is true or gives:

parameters:
  alpha:
    one: 1

if strict_constant_parameters is false

Default value for strict_constant_parameters is True

strict_constant_parameters: True

Nested References

References can now be nested, for example:

# nodes/node1.yml
parameters:
  alpha:
    one: ${beta:${alpha:two}}
    two: a
  beta:
    a: 99

reclass.py --nodeinfo node1 then gives:

parameters:
  alpha:
    one: 99
    two: a
  beta:
    a: 99

The ${beta:${alpha:two}} construct first resolves the ${alpha:two} reference to the value 'a', then resolves the reference ${beta:a} to the value 99.

Ignore overwritten missing references

Given the following classes:

# node1.yml
classes:
- class1
- class2
- class3

# class1.yml
parameters:
  a: ${x}

# class2.yml
parameters:
  a: ${y}

# class3.yml
parameters:
  y: 1

The parameter a only depends on the parameter y through the reference set in class2. The fact that the parameter x referenced in class1 is not defined does not affect the final value of the parameter a. For such overwritten missing references by default a warning is printed but no error is raised, providing the final value of the parameter being evaluated is a scalar. If the final value is a dictionary or list an error will always be raised in the case of a missing reference.

Default value is True to keep backward compatible behavior.

ignore_overwritten_missing_reference: True

Print summary of missed references

Instead of failing on the first undefinded reference error all missing reference errors are printed at once.

reclass --nodeinfo mynode
-> dontpanic
   Cannot resolve ${_param:kkk}, at mkkek3:tree:to:fail, in yaml_fs:///test/classes/third.yml
   Cannot resolve ${_param:kkk}, at mkkek3:tree:another:xxxx, in yaml_fs:///test/classes/third.yml
   Cannot resolve ${_param:kkk}, at mykey2:tree:to:fail, in yaml_fs:///test/classes/third.yml
group_errors: True

Use references in class names

Allows to use references in the class names.

References pointed to in class names cannot themselves reference another key, they should be simple strings.

To avoid pitfalls do not over-engineer your class references. They should be used only for core conditions and only for them. A short example: - system.wrodpress.db.${_class:database_backend}.

Best practices: - use references in class names always load your global class specification prior the reference is used. - structure your class references under parameters under one key (for example _class). - use class references as a kind of "context" or "global" available options you always know what they are set.

Class referencing for existing reclass users. Frequently when constructing your models you had to load or not load some classes based on your setup. In most cases this lead to fork of a model or introducing kind of template generator (like cookiecutter) to create a model based on the base "context" or "global" variables. Class referencing is a simple way how to avoid "pre-processors" like this and if/else conditions around class section.

Assuming following class setup:

  • node is loading third.yml class only

Classes:

#/etc/reclass/classes/global.yml
parameters:
  _class:
    env:
      override: 'env.dev'
  lab:
    name: default

#/etc/reclass/classes/lab/env/dev.yml
parameters:
  lab:
    name: dev

#/etc/reclass/classes/second.yml
classes:
  - global
  - lab.${_class:env:override}

#/etc/reclass/classes/third.yml
classes:
  - global
  - second

Reclass --nodeinfo then returns:

...
...
applications: []
environment: base
exports: {}
classes:
- global
- lab.${_class:env:override}
- second
parameters:
  _class:
    env:
      override: env.dev
  lab:
    name: dev
  ...
  ...

Load classes with relative names

Load referenced class from a relative location to the current class. To load class from relative location start the class uri with "." or ".." char. The only supported reference is to nested tree structure below the current class.

You are allowed to use syntax for relative uri to required class on any place on your model (first class loaded, init.yml, regular class .yml).

The feature is expected to improve flexibility while sharing classes between your models.

Please mpte that you can't use '..' without any calss following. If you want simply up in the sctructure, type in '..init'.

It's a new feature use it with care and mind that using "relative syntax" lower traceability of your pillar composition.

Example usage of relative class name using '.' and '..':

#/etc/reclass/classes/component/defaults.yml
classes:
  component:
    config:
      a: b
#/etc/reclass/classes/component/init.yml
classes:
  - .defaults
#/etc/reclass/classes/component/configuration/init.yml
classes:
  - ..defaults

Inventory Queries

Inventory querying works using a new key type - exports to hold values which other node definitions can read using a $[] query, for example with:

# nodes/node1.yml
exports:
  test_zero: 0
  test_one:
    name: ${name}
    value: 6
  test_two: ${dict}

parameters:
  name: node1
  dict:
    a: 1
    b: 2
  exp_value_test: $[ exports:test_two ]
  exp_if_test0: $[ if exports:test_zero == 0 ]
  exp_if_test1: $[ exports:test_one if exports:test_one:value == 7 ]
  exp_if_test2: $[ exports:test_one if exports:test_one:name == self:name ]

# nodes/node2.yml
exports:
  test_zero: 0
  test_one:
    name: ${name}
    value: 7
  test_two: ${dict}

parameters:
  name: node2
  dict:
    a: 11
    b: 22

running reclass.py --nodeinfo node1 gives (listing only the exports and parameters):

exports:
  test_one:
    name: node1
    value: 6
  test_two:
    a: 1
    b: 2
parameters:
  dict:
    a: 1
    b: 2
  exp_if_test0:
    - node1
    - node2
  exp_if_test1:
    node2:
      name: node2
      value: 7
  exp_if_test2:
    node1:
      name: node1
      value: 6
  exp_value_test:
    node1:
      a: 1
      b: 2
    node2:
      a: 11
      b: 22
  name: node1

Exports defined for a node can be a simple value or a reference to a parameter in the node definition. The $[] inventory queries are calculated for simple value expressions, $[ exports:key ], by returning a dictionary with an element ({ node_name: key value }) for each node which defines 'key' in the exports section. For tests with a preceeding value, $[ exports:key if exports:test_key == test_value ], the element ({ node_name: key value }) is only added to the returned dictionary if the test_key defined in the node exports section equals the test value. For tests without a preceeding value, $[ if exports:test_key == test_value ], a list of nodes which pass the test is returned. For either test form the test value can either be a simple value or a node parameter. And as well as an equality test a not equals test (!=) can also be used.

Inventory query options

By default inventory queries only look at nodes in the same environment as the querying node. This can be overriden using the +AllEnvs option:

$[ +AllEnvs exports:test ]

Any errors in rendering the export parameters for a node will give an error for the inventory query as a whole. This can be overriden using the +IgnoreErrors option:

$[ +IgnoreErrors exports:test ]

With the +IgnoreErrors option nodes which generate an error evaluating exports:test will be ignored.

Inventory query options can be combined:

$[ +AllEnvs +IgnoreErrors exports:test ]

Logical operators and/or

The logical operators and/or can be used in inventory queries:

$[ exports:test_value if exports:test_zero == 0 and exports:test_one == self:value ]

The individual elements of the if statement are evaluated and combined with the logical operators starting from the left and working to the right.

Inventory query example

Defining a cluster of machines using an inventory query, for example to open access to a database server to a group of nodes. Given exports/parameters for nodes of the form:

# for all nodes requiring access to the database server
  exports:
    host:
      ip_address: aaa.bbb.ccc.ddd
    cluster: _some_cluster_name_
# for the database server
parameters:
  cluster_name: production-cluster
  postgresql:
    server:
      clients: $[ exports:host:ip_address if exports:cluster == self:cluster_name ]

This will generate a dictionary with an entry for node where the export:cluster key for a node is equal to the parameter:cluster_name key of the node on which the inventory query is run on. Each entry in the generated dictionary will contain the value of the exports:host:ip_address key. The output dictionary (depending on node definitions) would look like:

node1:
  ip_address: aaa.bbb.ccc.ddd
node2:
  ip_address: www.xxx.yyy.zzz

For nodes where exports:cluster key is not defined or where the key is not equal to self:cluster_name no entry is made in the output dictionary.

In practise the exports:cluster key can be set using a parameter reference:

exports:
  cluster: ${cluster_name}
parameters:
  cluster_name: production-cluster

The above exports and parameter definitions could be put into a separate class and then included by nodes which require access to the database and included by the database server as well.

Compose node name

Nodes can be defined in subdirectories. However, node names (filename) must be unique across all subdirectories.

For example, the following file structure is invalid:

inventory/nodes/prod/mysql.yml
inventory/nodes/staging/mysql.yml

With setting:

compose_node_name: True       # default False

This adds the subfolder to the node name and the structure above can then be used. It generates the following reclass objects:

nodes:
  prod.mysql:
    ...
  staging.mysql:
    ...

If the subfolder path starts with the underscore character _, then the subfolder path is NOT added to the node name.

Git storage type

Reclass node and class yaml files can be read from a remote git repository with the yaml_git storage type. Use nodes_uri and classes_uri to define the git repos to use for nodes and classes. These can be the same repo.

For salt masters using ssh connections the private and public keys must be readable by the salt daemon, which requires the private key NOT be password protected. For stand alone reclass using ssh connections if the privkey and pubkey options are not defined then any in memory key (from ssh-add) will be used.

Salt master reclass config example:

storage_type:yaml_git
nodes_uri:
  # branch to use
  branch: master

  # cache directory (default: ~/.reclass/git/cache)
  cache_dir: /var/cache/reclass/git

  # lock directory (default: ~/.reclass/git/lock)
  lock_dir: /var/cache/reclass/lock

  # private key for ssh connections (no default, but will used keys stored
  # by ssh-add in memory if privkey and pubkey are not set)
  privkey: /root/salt_rsa
  # public key for ssh connections
  pubkey: /root/salt_rsa.pub

  repo: git+ssh://[email protected]:salt/nodes.git

classes_uri:
  # branch to use or __env__ to use the branch matching the node
  # environment name
  branch: __env__

  # cache directory (default: ~/.reclass/git/cache)
  cache_dir: /var/cache/reclass/git

  # lock directory (default: ~/.reclass/git/lock)
  lock_dir: /var/cache/reclass/lock

  # private key for ssh connections (no default, but will used keys stored
  # by ssh-add in memory if privkey and pubkey are not set)
  privkey: /root/salt_rsa
  # public key for ssh connections
  pubkey: /root/salt_rsa.pub

  # branch/env overrides for specific branches
  env_overrides:
  # prod env uses master branch
  - prod:
      branch: master
  # use master branch for nodes with no environment defined
  - none:
      branch: master

  repo: git+ssh://[email protected]:salt/site.git

  # root directory of the class hierarcy in git repo
  # defaults to root directory of git repo if not given
  root: classes

Mixed storage type

Use a mixture of storage types.

Salt master reclass config example, which by default uses yaml_git storage but overrides the location for classes for the pre-prod environment to use a directory on the local disc:

storage_type: mixed
nodes_uri:
  # storage type to use
  storage_type: yaml_git

  # yaml_git storage options
  branch: master
  cache_dir: /var/cache/reclass/git
  lock_dir: /var/cache/reclass/lock
  privkey: /root/salt_rsa
  pubkey: /root/salt_rsa.pub
  repo: git+ssh://[email protected]:salt/nodes.git

classes_uri:
  # storage type to use
  storage_type: yaml_git

  # yaml_git storage options
  branch: __env__
  cache_dir: /var/cache/reclass/git
  lock_dir: /var/cache/reclass/lock
  privkey: /root/salt_rsa
  pubkey: /root/salt_rsa.pub
  repo: git+ssh://[email protected]:salt/site.git
  root: classes

  env_overrides:
  - prod:
      branch: master
  - none:
      branch: master
  - pre-prod:
      # override storage type for this environment
      storage_type: yaml_fs
      # options for yaml_fs storage type
      uri: /srv/salt/env/pre-prod/classes