parameters_meta_schema.json

{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://nextflow.io",
  "title": "Nextflow Schema Meta-schema",
  "description": "Meta-schema to validate Nextflow parameter schema files",
  "type": "object",
  "properties": {
    "$schema": {
      "title": "schema",
      "type": "string",
      "minLength": 1
    },
    "$id": {
      "title": "ID URI",
      "type": "string",
      "minLength": 1
    },
    "title": {
      "title": "Title",
      "type": "string",
      "minLength": 1
    },
    "description": {
      "title": "Description",
      "type": "string",
      "minLength": 1
    },
    "type": {
      "title": "Top level type",
      "type": "string",
      "const": "object"
    },
    "$defs": {
      "title": "Parameter groups",
      "type": "object",
      "patternProperties": {
        "^.*$": {
          "type": "object",
          "required": ["title", "type", "properties"],
          "properties": {
            "title": {
              "type": "string",
              "minLength": 1
            },
            "type": {
              "const": "object"
            },
            "fa_icon": {
              "type": "string",
              "pattern": "^fa"
            },
            "description": {
              "type": "string"
            },
            "required": {
              "type": "array"
            },
            "properties": {
              "$ref": "#/$defs/parameterOptions"
            },
            "dependentRequired": {
              "type": "object",
              "additionalProperties": {
                "type": "array",
                "items": {
                  "type": "string"
                },
                "uniqueItems": true,
                "default": []
              }
            }
          }
        }
      }
    },
    "properties": {
      "$ref": "#/$defs/parameterOptions"
    },
    "dependentRequired": {
      "type": "object",
      "additionalProperties": {
        "type": "array",
        "items": {
          "type": "string"
        },
        "uniqueItems": true,
        "default": []
      }
    },
    "allOf": {
      "title": "Combine definition groups",
      "type": "array",
      "items": {
        "type": "object",
        "required": ["$ref"],
        "properties": {
          "$ref": {
            "type": "string",
            "pattern": "^#/\\$defs/[^/]+$"
          }
        }
      }
    }
  },
  "required": ["$schema", "$id", "title", "description", "type"],
  "$defs": {
    "typeAnnotation": {
      "type": "string",
      "enum": ["string", "boolean", "integer", "number", "null"]
    },
    "allTypes": {
      "type": ["integer", "boolean", "string", "number", "null"]
    },
    "nonNegativeInteger": {
      "type": "integer",
      "minimum": 0
    },
    "parameterOptions": {
      "type": "object",
      "patternProperties": {
        "^.*$": {
          "type": "object",
          "allOf": [
            { "$ref": "#/$defs/standardKeywords" },
            { "$ref": "#/$defs/customKeywords" }
          ],
          "required": ["type", "description"],
          "unevaluatedProperties": false
        }
      }
    },
    "standardKeywords": {
      "type": "object",
      "description": "Allowed standard JSON Schema properties.",
      "properties": {
        "type": {
          "description": "The type of the parameter value. Can be one or more of these: `['integer', 'boolean', 'number', 'string', 'null']`",
          "anyOf": [
            { "$ref": "#/$defs/typeAnnotation" },
            {
              "type": "array",
              "items": { "$ref": "#/$defs/typeAnnotation" }
            }
          ]
        },
        "format": {
          "type": "string",
          "description": "The format of a parameter value with the 'string' type. This is used for additional validation on the structure of the value.",
          "enum": [
            "file-path",
            "directory-path",
            "path",
            "file-path-pattern",
            "date-time",
            "date",
            "time",
            "email",
            "uri",
            "regex"
          ]
        },
        "pattern": {
          "type": "string",
          "format": "regex",
          "minLength": 1,
          "description": "Check a parameter value of 'string' type against a regex pattern"
        },
        "description": {
          "type": "string",
          "description": "The description of the current parameter"
        },
        "default": {
          "$ref": "#/$defs/allTypes",
          "description": "Specifies a default value to use for this parameter"
        },
        "examples": {
          "type": "array",
          "items": {
            "$ref": "#/$defs/allTypes"
          },
          "description": "A list of examples for the current parameter"
        },
        "deprecated": {
          "type": "boolean",
          "description": "States that the parameter is deprecated. Please provide a nice deprecation message using 'errorMessage'"
        },
        "minLength": {
          "$ref": "#/$defs/nonNegativeInteger",
          "description": "The minimum length a 'string' parameter value should be"
        },
        "maxLength": {
          "$ref": "#/$defs/nonNegativeInteger",
          "description": "The maximum length a 'string' parameter value should be"
        },
        "minimum": {
          "type": "number",
          "description": "The mimimum value an 'integer' or 'number' parameter value should be"
        },
        "exclusiveMinimum": {
          "type": "number",
          "description": "The exclusive mimimum value an 'integer' or 'number' parameter value should be"
        },
        "maximum": {
          "type": "number",
          "description": "The maximum value an 'integer' or 'number' parameter value should be"
        },
        "exclusiveMaximum": {
          "type": "number",
          "description": "The exclusive maximum value an 'integer' or 'number' parameter value should be"
        },
        "multipleOf": {
          "type": "number",
          "description": "The 'integer' or 'number' parameter value should be a multiple of this value"
        },
        "enum": {
          "type": "array",
          "uniqueItems": true,
          "items": {
            "$ref": "#/$defs/allTypes"
          },
          "description": "The parameter value should be one of the values specified in this enum array"
        },
        "const": {
          "$ref": "#/$defs/allTypes",
          "description": "The parameter value should be equal to this value"
        }
      }
    },
    "customKeywords": {
      "type": "object",
      "description": "Additional custom JSON Schema properties.",
      "properties": {
        "errorMessage": {
          "type": "string",
          "minLength": 1,
          "description": "NON STANDARD OPTION: The custom error message to display in case validation against this parameter fails. Can also be used as a deprecation message if 'deprecated' is true"
        },
        "exists": {
          "type": "boolean",
          "description": "NON STANDARD OPTION: Check if a file exists. This parameter value needs to be a `string` type with one of these formats: `['path', 'file-path', 'directory-path', 'file-path-pattern']`"
        },
        "schema": {
          "type": "string",
          "minLength": 1,
          "pattern": "\\.json$",
          "description": "NON STANDARD OPTION: Check the given file against a schema passed to this keyword. Will only work when type is `string` and format is `path` or `file-path`"
        },
        "help_text": {
          "type": "string",
          "description": "NON STANDARD OPTION: A more detailed help text"
        },
        "fa_icon": {
          "type": "string",
          "pattern": "^fa",
          "description": "NON STANDARD OPTION: A font awesome icon to use in the nf-core parameter documentation"
        },
        "hidden": {
          "type": "boolean",
          "description": "NON STANDARD OPTION: Hide this parameter from the help message and documentation"
        },
        "mimetype": {
          "type": "string",
          "description": "NON STANDARD OPTION: The MIME type of the parameter value",
          "deprecated": true,
          "errorMessage": "The 'mimetype' keyword is deprecated. Use 'pattern' or 'format' instead."
        }
      },
      "dependentSchemas": {
        "exists": {
          "$comment": "This checks if the type is a 'string' and the format corresponds to a file or directory when 'exists' is used.",
          "properties": {
            "type": { "const": "string" },
            "format": {
              "enum": [
                "path",
                "file-path",
                "file-path-pattern",
                "directory-path"
              ]
            }
          }
        },
        "schema": {
          "$comment": "This checks if the type is a 'string' and the format is 'path' or 'file-path'",
          "properties": {
            "type": { "const": "string" },
            "format": {
              "enum": ["path", "file-path"]
            }
          }
        }
      }
    }
  }
}