{
  "$schema": "http://json-schema.org/draft-06/schema#",
  "$id": "http://kubeflow.org/pipelines/components.json_schema.json",
  "allOf": [{"$ref": "#/definitions/ComponentSpec"}],

  "definitions": {
    "TypeSpecType": {
      "oneOf": [
        {"type": "string"},
        {"type": "object", "additionalProperties": {"$ref": "#/definitions/TypeSpecType"}}
      ]
    },

    "InputSpec": {
      "description": "Describes the component input specification",
      "type": "object",
      "required": ["name"],
      "properties": {
        "name": {"type": "string"},
        "type": {"$ref": "#/definitions/TypeSpecType"},
        "description": {"type": "string"},
        "default": {"type": "string"},
        "optional": {"type": "boolean", "default": false}
      },
      "additionalProperties": false
    },

    "OutputSpec": {
      "description": "Describes the component output specification",
      "type": "object",
      "required": ["name"],
      "properties": {
        "name": {"type": "string"},
        "type": {"$ref": "#/definitions/TypeSpecType"},
        "description": {"type": "string"}
      },
      "additionalProperties": false
    },

    "InputValuePlaceholder": {
      "description": "Represents the command-line argument placeholder that will be replaced at run-time by the input argument value.",
      "type": "object",
      "required": ["inputValue"],
      "properties": {
        "inputValue" : {
          "description": "Name of the input.",
          "type": "string"
        }
      },
      "additionalProperties": false
    },

    "InputPathPlaceholder": {
      "description": "Represents the command-line argument placeholder that will be replaced at run-time by a local file path pointing to a file containing the input argument value.",
      "type": "object",
      "required": ["inputPath"],
      "properties": {
        "inputPath" : {
          "description": "Name of the input.",
          "type": "string"
        }
      },
      "additionalProperties": false
    },

    "OutputPathPlaceholder": {
      "description": "Represents the command-line argument placeholder that will be replaced at run-time by a local file path pointing to a file where the program should write its output data.",
      "type": "object",
      "required": ["outputPath"],
      "properties": {
        "outputPath" : {
          "description": "Name of the output.",
          "type": "string"
        }
      },
      "additionalProperties": false
    },

    "StringOrPlaceholder": {
      "oneOf": [
        {"type": "string"},
        {"$ref": "#/definitions/InputValuePlaceholder"},
        {"$ref": "#/definitions/InputPathPlaceholder"},
        {"$ref": "#/definitions/OutputPathPlaceholder"},
        {"$ref": "#/definitions/ConcatPlaceholder"},
        {"$ref": "#/definitions/IfPlaceholder"}
      ]
    },

    "ConcatPlaceholder": {
      "description": "Represents the command-line argument placeholder that will be replaced at run-time by the concatenated values of its items.",
      "type": "object",
      "required": ["concat"],
      "properties": {
        "concat" : {
          "description": "Items to concatenate",
          "type": "array",
          "items": {"$ref": "#/definitions/StringOrPlaceholder"}
        }
      },
      "additionalProperties": false
    },

    "IsPresentPlaceholder": {
      "description": "Represents the command-line argument placeholder that will be replaced at run-time by a boolean value specifying whether the caller has passed an argument for the specified optional input.",
      "type": "object",
      "properties": {
        "isPresent": {
          "description": "Name of the input.",
          "type": "string"
        }
      },
      "additionalProperties": false
    },

    "IfConditionArgumentType": {
      "oneOf": [
        {"$ref": "#/definitions/IsPresentPlaceholder"},
        {"type": "boolean"},
        {"type": "string"},
        {"$ref": "#/definitions/InputValuePlaceholder"}
      ]
    },

    "IfPlaceholder": {
      "description": "Represents the command-line argument placeholder that will be replaced at run-time by a boolean value specifying whether the caller has passed an argument for the specified optional input.",
      "type": "object",
      "required": ["if"],
      "properties": {
        "if" : {
          "type": "object",
          "required": ["cond", "then"],
          "properties": {
            "cond": {"$ref": "#/definitions/IfConditionArgumentType"},
            "then": {"$ref": "#/definitions/StringOrPlaceholder"},
            "else": {"$ref": "#/definitions/StringOrPlaceholder"}
          }
        }
      }
    },

    "ContainerSpec": {
      "type": "object",
      "required": ["image"],
      "properties": {
        "image": {
          "description": "Docker image name.",
          "$ref": "#/definitions/StringOrPlaceholder"
        },
        "command": {
          "description": "Entrypoint array. Not executed within a shell. The docker image's ENTRYPOINT is used if this is not provided.",
          "type": "array",
          "items": {"$ref": "#/definitions/StringOrPlaceholder"}
        },
        "args": {
          "description": "Arguments to the entrypoint. The docker image's CMD is used if this is not provided.",
          "type": "array",
          "items": {"$ref": "#/definitions/StringOrPlaceholder"}
        },
        "env": {
          "description": "List of environment variables to set in the container.",
          "type": "object",
          "additionalProperties": {"$ref": "#/definitions/StringOrPlaceholder"}
        },
        "unconfigurableOutputPaths": {
          "description": "Legacy. Deprecated. Can be used to specify local output file paths for containers that do not allow setting the path of some output using command-line.",
          "type": "object",
          "additionalProperties": {"type": "string"}
        }
      },
      "additionalProperties": false
    },

    "ContainerImplementation": {
      "description": "Represents the container component implementation.",
      "type": "object",
      "required": ["container"],
      "properties": {
        "container": {"$ref": "#/definitions/ContainerSpec"}
      }
    },

    "ImplementationType": {
      "oneOf": [
        {"$ref": "#/definitions/ContainerImplementation"},
        {"$ref": "#/definitions/GraphImplementation"}
      ]
    },

    "ComponentSpec": {
      "description": "Component specification. Describes the metadata (name, description, source), the interface (inputs and outputs) and the implementation of the component.",
      "type": "object",
      "required": ["implementation"],
      "properties": {
        "name": {"type": "string"},
        "description": {"type": "string"},
        "inputs": {"type": "array", "items": {"$ref": "#/definitions/InputSpec"}},
        "outputs": {"type": "array", "items": {"$ref": "#/definitions/OutputSpec"}},
        "implementation": {"$ref": "#/definitions/ImplementationType"}
      },
      "additionalProperties": false
    },

    "ComponentReference": {
      "description": "Component reference. Contains information that can be used to locate and load a component by name, digest or URL",
      "type": "object",
      "properties": {
        "name": {"type": "string"},
        "digest": {"type": "string"},
        "tag": {"type": "string"},
        "url": {"type": "string"},
        "spec": {"$ref": "#/definitions/ComponentSpec"}
      },
      "additionalProperties": false
    },

    "GraphInputArgument": {
      "description": "Represents the component argument value that comes from the graph component input.",
      "type": "object",
      "required": ["graphInput"],
      "properties": {
        "graphInput": {
          "description": "References the input of the graph/pipeline.",
          "type": "object",
          "required": ["inputName"],
          "properties": {
            "inputName": {"type": "string"},
            "type": {"$ref": "#/definitions/TypeSpecType"}
          },
          "additionalProperties": false
        }
      },
      "additionalProperties": false
    },

    "TaskOutputArgument": {
      "description": "Represents the component argument value that comes from the output of a sibling task.",
      "type": "object",
      "required": ["taskOutput"],
      "properties": {
        "taskOutput": {
          "description": "References the output of a sibling task.",
          "type": "object",
          "required": ["taskId", "outputName"],
          "properties": {
            "taskId": {"type": "string"},
            "outputName": {"type": "string"},
            "type": {"$ref": "#/definitions/TypeSpecType"}
          },
          "additionalProperties": false
        }
      },
      "additionalProperties": false
    },

    "ArgumentType": {
      "oneOf": [
        {"type": "string"},
        {"$ref": "#/definitions/GraphInputArgument"},
        {"$ref": "#/definitions/TaskOutputArgument"}
      ]
    },

    "TwoArgumentOperands": {
      "description": "Pair of operands for a binary operation.",
      "type": "object",
      "required": ["op1", "op2"],
      "properties": {
        "op1":  {"$ref": "#/definitions/ArgumentType"},
        "op2":  {"$ref": "#/definitions/ArgumentType"}
      },
      "additionalProperties": false
    },

    "TwoLogicalOperands": {
      "description": "Pair of operands for a binary logical operation.",
      "type": "object",
      "required": ["op1", "op2"],
      "properties": {
        "op1":  {"$ref": "#/definitions/PredicateType"},
        "op2":  {"$ref": "#/definitions/PredicateType"}
      },
      "additionalProperties": false
    },

    "PredicateType": {
      "oneOf": [
        {"type": "object", "required": ["=="], "properties": {"==":  {"$ref": "#/definitions/TwoArgumentOperands"}}},
        {"type": "object", "required": ["!="], "properties": {"!=":  {"$ref": "#/definitions/TwoArgumentOperands"}}},
        {"type": "object", "required": [">"], "properties": {">":  {"$ref": "#/definitions/TwoArgumentOperands"}}},
        {"type": "object", "required": [">="], "properties": {">=":  {"$ref": "#/definitions/TwoArgumentOperands"}}},
        {"type": "object", "required": ["<"], "properties": {"<":  {"$ref": "#/definitions/TwoArgumentOperands"}}},
        {"type": "object", "required": ["<="], "properties": {"<=":  {"$ref": "#/definitions/TwoArgumentOperands"}}},

        {"type": "object", "required": ["and"], "properties": {"and":  {"$ref": "#/definitions/TwoLogicalOperands"}}},
        {"type": "object", "required": ["or"], "properties": {"or":  {"$ref": "#/definitions/TwoLogicalOperands"}}},

        {"type": "object", "required": ["not"], "properties": {"not":  {"$ref": "#/definitions/PredicateType"}}}
      ]
    },

    "RetryStrategySpec": {
      "description": "Optional configuration that specifies how the task should be retried if it fails.",
      "type": "object",
      "properties": {
        "maxRetries": {"type": "integer"}
      },
      "additionalProperties": false
    },

    "CachingStrategySpec": {
      "description": "Optional configuration that specifies how the task execution may be skipped if the output data exist in cache.",
      "type": "object",
      "properties": {
        "maxCacheStaleness": {"type": "string", "format": "duration"}
      },
      "additionalProperties": false
    },

    "ExecutionOptionsSpec": {
      "description": "Optional configuration that specifies how the task should be executed. Can be used to set some platform-specific options.",
      "type": "object",
      "properties": {
        "retryStrategy": {"$ref": "#/definitions/RetryStrategySpec"},
        "cachingStrategy": {"$ref": "#/definitions/CachingStrategySpec"}
      },
      "additionalProperties": false
    },
    
    "TaskSpec": {
      "description": "'Task specification. Task is a configured component - a component supplied with arguments and other applied configuration changes.",
      "type": "object",
      "required": ["componentRef"],
      "properties": {
        "componentRef": {"$ref": "#/definitions/ComponentReference"},
        "arguments": {"type": "object", "additionalProperties": {"$ref": "#/definitions/ArgumentType"}},
        "isEnabled": {"$ref": "#/definitions/PredicateType"},
        "executionOptions": {"$ref": "#/definitions/ExecutionOptionsSpec"}
      },
      "additionalProperties": false
    },

    "GraphSpec": {
      "description": "Describes the graph component implementation. It represents a graph of component tasks connected to the upstream sources of data using the argument specifications. It also describes the sources of graph output values.",
      "type": "object",
      "required": ["tasks"],
      "properties": {
        "tasks": {"type": "object", "additionalProperties": {"$ref": "#/definitions/TaskSpec"}},
        "outputValues": {"type": "object", "additionalProperties": {"$ref": "#/definitions/TaskOutputArgument"}}
      },
      "additionalProperties": false
    },

    "GraphImplementation": {
      "description": "Represents the graph component implementation.",
      "type": "object",
      "required": ["graph"],
      "properties": {
        "graph": {"$ref": "#/definitions/GraphSpec"}
      },
      "additionalProperties": false
    },

    "PipelineRunSpec": {
      "description": "The object that can be sent to the backend to start a new Run.",
      "type": "object",
      "required": ["rootTask"],
      "properties": {
        "rootTask": {"$ref": "#/definitions/TaskSpec"},
        "onExitTask": {"$ref": "#/definitions/TaskSpec"}
      },
      "additionalProperties": false
    }
  }
}
