Crossplane Composition

{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://github.com/api-evangelist/crossplane/blob/main/composition-schema.json",
  "title": "Crossplane Composition",
  "description": "Schema for a Crossplane Composition that defines how to compose infrastructure resources into higher-level composite resources by mapping patches and configuring managed resources.",
  "type": "object",
  "required": ["apiVersion", "kind", "metadata", "spec"],
  "properties": {
    "apiVersion": {
      "type": "string",
      "const": "apiextensions.crossplane.io/v1",
      "description": "API version for the Crossplane Composition resource."
    },
    "kind": {
      "type": "string",
      "const": "Composition",
      "description": "Resource kind identifier."
    },
    "metadata": {
      "type": "object",
      "description": "Standard Kubernetes object metadata.",
      "required": ["name"],
      "properties": {
        "name": {
          "type": "string",
          "description": "Unique name for this Composition."
        },
        "labels": {
          "type": "object",
          "description": "Key-value pairs for organizing and selecting Compositions.",
          "additionalProperties": { "type": "string" }
        },
        "annotations": {
          "type": "object",
          "description": "Non-identifying metadata for the Composition.",
          "additionalProperties": { "type": "string" }
        }
      }
    },
    "spec": {
      "type": "object",
      "description": "Specification for the Composition defining resource templates and patches.",
      "required": ["compositeTypeRef", "resources"],
      "properties": {
        "compositeTypeRef": {
          "type": "object",
          "description": "Reference to the CompositeResourceDefinition (XRD) this Composition satisfies.",
          "required": ["apiVersion", "kind"],
          "properties": {
            "apiVersion": {
              "type": "string",
              "description": "API version of the composite resource type."
            },
            "kind": {
              "type": "string",
              "description": "Kind of the composite resource type."
            }
          }
        },
        "writeConnectionSecretsToNamespace": {
          "type": "string",
          "description": "Namespace where connection secrets for composed resources are written."
        },
        "patchSets": {
          "type": "array",
          "description": "Reusable sets of patches that can be referenced by composed resources.",
          "items": {
            "type": "object",
            "required": ["name", "patches"],
            "properties": {
              "name": {
                "type": "string",
                "description": "Name used to reference this patch set."
              },
              "patches": {
                "type": "array",
                "description": "Patches included in this set.",
                "items": { "$ref": "#/$defs/patch" }
              }
            }
          }
        },
        "resources": {
          "type": "array",
          "description": "List of composed resource templates that make up this Composition.",
          "items": {
            "type": "object",
            "required": ["name", "base"],
            "properties": {
              "name": {
                "type": "string",
                "description": "Unique name identifying this composed resource within the Composition."
              },
              "base": {
                "type": "object",
                "description": "Base resource manifest used as a template for provisioning.",
                "required": ["apiVersion", "kind"],
                "properties": {
                  "apiVersion": {
                    "type": "string",
                    "description": "API version of the managed resource."
                  },
                  "kind": {
                    "type": "string",
                    "description": "Kind of the managed resource."
                  },
                  "spec": {
                    "type": "object",
                    "description": "Specification for the base managed resource."
                  },
                  "metadata": {
                    "type": "object",
                    "description": "Metadata for the base managed resource."
                  }
                }
              },
              "patches": {
                "type": "array",
                "description": "Patches to apply from the composite resource to this composed resource.",
                "items": { "$ref": "#/$defs/patch" }
              },
              "connectionDetails": {
                "type": "array",
                "description": "Connection details to expose from this composed resource.",
                "items": {
                  "type": "object",
                  "properties": {
                    "fromConnectionSecretKey": {
                      "type": "string",
                      "description": "Key in the composed resource connection secret."
                    },
                    "name": {
                      "type": "string",
                      "description": "Name of the connection detail in the composite resource."
                    },
                    "type": {
                      "type": "string",
                      "enum": ["FromConnectionSecretKey", "FromFieldPath", "FromValue"],
                      "description": "Type of connection detail source."
                    },
                    "value": {
                      "type": "string",
                      "description": "Static value for the connection detail."
                    }
                  }
                }
              },
              "readinessChecks": {
                "type": "array",
                "description": "Checks to determine if this composed resource is ready.",
                "items": {
                  "type": "object",
                  "required": ["type"],
                  "properties": {
                    "type": {
                      "type": "string",
                      "enum": ["MatchString", "MatchInteger", "NonEmpty", "None", "MatchCondition", "MatchTrue", "MatchFalse"],
                      "description": "Type of readiness check."
                    },
                    "fieldPath": {
                      "type": "string",
                      "description": "Path to the field to check for readiness."
                    },
                    "matchString": {
                      "type": "string",
                      "description": "Expected string value for MatchString checks."
                    },
                    "matchInteger": {
                      "type": "integer",
                      "description": "Expected integer value for MatchInteger checks."
                    }
                  }
                }
              }
            }
          }
        },
        "mode": {
          "type": "string",
          "enum": ["Resources", "Pipeline"],
          "description": "Mode of the Composition, either Resources or Pipeline."
        },
        "pipeline": {
          "type": "array",
          "description": "Pipeline steps for Pipeline mode Compositions.",
          "items": {
            "type": "object",
            "required": ["step", "functionRef"],
            "properties": {
              "step": {
                "type": "string",
                "description": "Name of this pipeline step."
              },
              "functionRef": {
                "type": "object",
                "description": "Reference to a Composition Function.",
                "required": ["name"],
                "properties": {
                  "name": {
                    "type": "string",
                    "description": "Name of the Composition Function to invoke."
                  }
                }
              },
              "input": {
                "type": "object",
                "description": "Input to pass to the Composition Function."
              }
            }
          }
        }
      }
    }
  },
  "$defs": {
    "patch": {
      "type": "object",
      "description": "A patch that maps values between composite and composed resources.",
      "properties": {
        "type": {
          "type": "string",
          "enum": [
            "FromCompositeFieldPath",
            "ToCompositeFieldPath",
            "CombineFromComposite",
            "CombineToComposite",
            "PatchSet"
          ],
          "description": "Type of patch operation."
        },
        "fromFieldPath": {
          "type": "string",
          "description": "Source field path in the composite or composed resource."
        },
        "toFieldPath": {
          "type": "string",
          "description": "Destination field path in the composed or composite resource."
        },
        "patchSetName": {
          "type": "string",
          "description": "Name of the PatchSet to apply (when type is PatchSet)."
        },
        "transforms": {
          "type": "array",
          "description": "Transforms to apply to the patched value.",
          "items": {
            "type": "object",
            "required": ["type"],
            "properties": {
              "type": {
                "type": "string",
                "enum": ["map", "match", "math", "string", "convert"],
                "description": "Type of transform to apply."
              },
              "map": {
                "type": "object",
                "description": "Map transform key-value pairs.",
                "additionalProperties": { "type": "string" }
              },
              "math": {
                "type": "object",
                "description": "Math transform configuration.",
                "properties": {
                  "type": { "type": "string" },
                  "multiply": { "type": "number" }
                }
              },
              "string": {
                "type": "object",
                "description": "String transform configuration.",
                "properties": {
                  "type": { "type": "string" },
                  "fmt": { "type": "string" }
                }
              },
              "convert": {
                "type": "object",
                "description": "Type conversion transform.",
                "properties": {
                  "toType": { "type": "string" }
                }
              }
            }
          }
        },
        "policy": {
          "type": "object",
          "description": "Policy for handling missing field paths.",
          "properties": {
            "fromFieldPath": {
              "type": "string",
              "enum": ["Optional", "Required"],
              "description": "Policy for missing source field."
            }
          }
        }
      }
    }
  }
}