id: yaml_config
label: YAML Config
flags: [ show_id, python ]

parameters:
-   id: config_file
    label: Config File
    dtype: file_open
    default: ""
-   id: schema_file
    label: Config Schema
    dtype: file_open
    default: ""
# Not my favorite thing because it doesn't explicitly close the file, but
# it should be okay.  The garbage collector will take care of it.
value: "${ yaml.safe_load(open(config_file)) }"

asserts:
- ${ schema_file == "" or validate(yaml.safe_load(open(config_file)), json.load(open(schema_file))) is None }

templates:
    imports: |-
        import json
        import yaml
        from jsonschema import validate
    var_make: "with open(${config_file}) as fid:\n\
              \    self.${id} = ${id} = yaml.safe_load(fid)\n\
              self.${id}_schema = ${id}_schema = ${schema_file}\n\
              if ${id}_schema:\n\
              \    with open(${id}_schema) as fid:\n\
              \        validate(${id}, json.load(fid))"

documentation: |-
    This block represents a yaml config file that is read in as a dictionary.

    The values can be used directly when instantiating blocks.  For example,
    Sample Rate: yaml_config["samp_rate"]

    Optionally, a json schema can be specified to validate the configuration.
    It may sound odd to use a json schema for a yaml file, but it works and 
    jsonschema is a rich specification.

    For example, you could have a yaml file that contains:
    samp_rate: 1e6

    And a schema that contains
    {
      "type": "object",
      "properties": {
        "samp_rate": {"type": "number", "exclusiveMinimum": 0}
      }
    }

    If the id of this block is yaml_config_0, then you can access the samp rate
    in other blocks as yaml_config_0["samp_rate"]


file_format: 1