tripleo-heat-templates/sample-env-generator

Sample Environment Generator

This is a tool to automate the generation of our sample environment files. It takes a yaml file as input, and based on the environments defined in that file generates a number of sample environment files from the parameters in the Heat templates.

Usage

The simplest case is when an existing sample environment needs to be updated to reflect changes in the templates. Use the tox genconfig target to do this:

tox -e genconfig

Note

The tool should be run from the root directory of the tripleo-heat-templates project.

If a new sample environment is needed, it should be added to the appropriate file in the sample-env-generator/ directory. The existing entries in the files can be used as examples, and a more detailed explanation of the different available keys is below:

Top-level:

• environments: This is the top-level key in the file. All other keys below should appear in a list of dictionaries that define environments.

Environment-specific:

• name: the output file will be this name + .yaml, in the environments directory.
• title: a human-readable title for the environment.
• description: A description of the environment. Will be included as a comment at the top of the sample file.
• files: The Heat templates containing the parameter definitions for the environment. Should be specified as a path relative to the root of the tripleo-heat-templates project. For example: puppet/extraconfig/tls/ca-inject.yaml:. Each filename should be a YAML dictionary that contains a parameters entry.
• parameters: There should be one parameters entry per file in the files section (see the example configuration below). This can be either a list of parameters related to the environment, which is necessary for templates like overcloud.yaml, or the string 'all', which indicates that all parameters from the file should be included.
• static: Can be used to specify that certain parameters must not be changed. Examples would be the EnableSomething params in the templates. When writing a sample config for Something, EnableSomething: True would be a static param, since it would be nonsense to include the environment with it set to any other value.
• sample_values: Sometimes it is useful to include a sample value for a parameter that is not the parameter's actual default. An example of this is the SSLCertificate param in the enable-tls environment file.
• resource_registry: Many environments also need to pass resource_registry entries when they are used. This can be used to specify that in the configuration file.
• children: For environments that share a lot of common values but may need minor variations for different use cases, sample environment entries can be nested. children takes a list of environments with the same structure as the top-level environments key. The main difference is that all keys are optional, and any that are omitted will be inherited from the parent environment definition.

Some behavioral notes:

• Parameters without default values will be marked as mandatory to indicate that the user must set a value for them.
• It is no longer recommended to set parameters using the parameters section. Instead, all parameters should be set as parameter_defaults which will work regardless of whether the parameter is top-level or nested. Therefore, the tool will always set parameters in the parameter_defaults section.
• Parameters whose name begins with the _ character are treated as private. This indicates that the parameter value will be passed in from another template and does not need to be exposed directly to the user.

If adding a new environment, don't forget to add the new file to the git repository so it will be included with the review.

Example

Given a Heat template named example.yaml that looks like:

parameters:
  EnableExample:
    default: False
    description: Enable the example feature
    type: boolean
  ParamOne:
    default: one
    description: First example param
    type: string
  ParamTwo:
    description: Second example param
    type: number
  _PrivateParam:
    default: does not matter
    description: Will not show up
    type: string

And an environment generator entry that looks like:

environments:
  -
    name: example
    title: Example Environment
    description: |
      An example environment demonstrating how to use the sample
      environment generator.  This text will be included at the top
      of the generated file as a comment.
    files:
      example.yaml:
        parameters: all
    sample_values:
      EnableExample: True
    static:
      - EnableExample
    resource_registry:
      OS::TripleO::ExampleData: ../extraconfig/example.yaml

The generated environment file would look like:

# *******************************************************************
# This file was created automatically by the sample environment
# generator. Developers should use `tox -e genconfig` to update it.
# Users are recommended to make changes to a copy of the file instead
# of the original, if any customizations are needed.
# *******************************************************************
# title: Example Environment
# description: |
#   An example environment demonstrating how to use the sample
#   environment generator.  This text will be included at the top
#   of the generated file as a comment.
parameter_defaults:
  # First example param
  # Type: string
  ParamOne: one

  # Second example param
  # Mandatory. This parameter must be set by the user.
  # Type: number
  ParamTwo: <None>

  # ******************************************************
  # Static parameters - these are values that must be
  # included in the environment but should not be changed.
  # ******************************************************
  # Enable the example feature
  # Type: boolean
  EnableExample: True

  # *********************
  # End static parameters
  # *********************
resource_registry:
  OS::TripleO::ExampleData: ../extraconfig/example.yaml