Parameters

The SOMOD Parameters define the configurations for the module. ui/config.yaml and serverless/template.yaml refer to the parameters available in the parameters.yaml.

ui/config.yaml and serverless/template.yaml can refer to the parameters from the current and all dependency modules.

When more than one dependency module has the same parameter defined, the conflict is resolved using the namespaces.

SOMOD build command validates parameters.yaml and generates build/parameters.json. SOMOD prepare command combines parameters from all dependency modules and updates the missing values in the root parameters.json. The prepare command also generates the NextJs and AWS SAM configuration files from parameters.json in the root.

project-root
    |
    +-- node_modules                               --+
    |       +-- module-a                             |
    |               +-- build/                       | FROM DEPENDENCIES
    |                     +--parameters.json         |
    |                                              --+
    |
    +-- build/                                     --+
    |      +-- parameters.json                       | BUILD OUTPUT
    |                                              --+
    |
    +-- parameters.yaml                            --- SOURCE
    |
    +-- parameters.json                            --- PREPARED

There are three parameter files in a module.

• The developer creates the parameters.yaml in the root directory.
• SOMOD build command generates the build/parameters.json from parameters.yaml.
• parameters.json at the root directory contains a JSON object of parameter names and values. SOMOD prepare command uses the values in parameters.json to create .env, next.config.js, and template.yaml.

Anatomy of parameters.yaml

Parameters:
  mycomponent.param1: # parameter name
    type: text # parameter schema follows the structure of form-input-schema
    default: waw
  mycomponent.param2:
    type: email
    default: me@example.com
Schemas:
  mycomponent.param2.domain.check:
    # valid json schema to be applied on the parameters object
Groups:
  mycomponent:
    label: My Group
    helpText: >
      group helps to combine multiple parameters when 
      a client library tries to display UI 
      to collect data for the parameters

The parameters.yaml contains three optional sections, Parameters, Schemas, and Groups

• Parameters
  Parameters is a map of the parameter name to the input schema.

  • Parameter name
    The parameter name has the following constraints

    • must contain only the alphabets, numbers, and dots
    • can have a maximum of 128 characters.
    • must start with the alphabet
    • and must have at least one dot

  • Parameter Input Schema
    SOMOD uses Form Input Schema to define the validation constraints for the parameters.

• Schemas
  Provide additional schema to be applied before using the parameter values during preparation.

  Map of schema name to JSONSchema7. Every Schema from all dependency modules is validated during preparation.

• Groups
  Provide Group metadata for the Parameters Grouping.

  All parameters and groups whose name starts with the name of the current group are children of the current group.

Parameter Name, Schema Name and Group Name are namespaced.

In the Next Chapter, let us understand the namespaces in SOMOD.