{
    "$id": "docs/spec/spans/span.json",
    "type": "object",
    "description": "An event captured by an agent occurring in a monitored service",
    "allOf": [
        { "$ref": "../timestamp_epoch.json" },
        { "$ref": "../span_type.json" },
        { "$ref": "../span_subtype.json" },
        {
            "properties": {
                "id": {
                    "description": "Hex encoded 64 random bits ID of the span.",
                    "type": "string",
                    "maxLength": 1024
                },
                "transaction_id": {
                    "type": ["string", "null"],
                    "description": "Hex encoded 64 random bits ID of the correlated transaction.",
                    "maxLength": 1024
                },
                "trace_id": {
                    "description": "Hex encoded 128 random bits ID of the correlated trace.",
                    "type": "string",
                    "maxLength": 1024
                },
                "parent_id": {
                    "description": "Hex encoded 64 random bits ID of the parent transaction or span.",
                    "type": "string",
                    "maxLength": 1024
                },
                "start": {
                    "type": ["number", "null"],
                    "description": "Offset relative to the transaction's timestamp identifying the start of the span, in milliseconds"
                },
                "action": {
                    "type": ["string", "null"],
                    "description": "The specific kind of event within the sub-type represented by the span (e.g. query, connect)",
                    "maxLength": 1024
                },
                "context": {
                    "type": ["object", "null"],
                    "description": "Any other arbitrary data captured by the agent, optionally provided by the user",
                    "properties": {
                        "db": {
                            "type": ["object", "null"],
                            "description": "An object containing contextual data for database spans",
                            "properties": {
                                "instance": {
                                    "type": ["string", "null"],
                                    "description": "Database instance name"
                                },
                                "link": {
                                    "type": ["string", "null"],
                                    "maxLength": 1024,
                                    "description": "Database link"
                                },
                                "statement": {
                                    "type": ["string", "null"],
                                    "description": "A database statement (e.g. query) for the given database type"
                                },
                                "type": {
                                    "type": ["string", "null"],
                                    "description": "Database type. For any SQL database, \"sql\". For others, the lower-case database category, e.g. \"cassandra\", \"hbase\", or \"redis\""
                                },
                                "user": {
                                    "type": ["string", "null"],
                                    "description": "Username for accessing database"
                                }
                            }
                        },
                        "http": {
                            "type": ["object", "null"],
                            "description": "An object containing contextual data of the related http request.",
                            "properties": {
                                "url": {
                                    "type": ["string", "null"],
                                    "description": "The raw url of the correlating http request."
                                },
                                "status_code": {
                                    "type": ["integer", "null"],
                                    "description": "The status code of the http request."
                                },
                                "method": {
                                    "type": ["string", "null"],
                                    "maxLength": 1024,
                                    "description": "The method of the http request."
                                }
                            }
                        },
                        "tags": {
                            "$ref": "../tags.json"
                        },
                        "service": {
                            "description": "Service related information can be sent per event. Provided information will override the more generic information from metadata, non provided fields will be set according to the metadata information.",
                            "properties": {
                                "agent": {
                                    "description": "Name and version of the Elastic APM agent",
                                    "type": [
                                        "object",
                                        "null"
                                    ],
                                    "properties": {
                                        "name": {
                                            "description": "Name of the Elastic APM agent, e.g. \"Python\"",
                                            "type": [
                                                "string",
                                                "null"
                                            ],
                                            "maxLength": 1024
                                        },
                                        "version": {
                                            "description": "Version of the Elastic APM agent, e.g.\"1.0.0\"",
                                            "type": [
                                                "string",
                                                "null"
                                            ],
                                            "maxLength": 1024
                                        },
                                        "ephemeral_id": {
                                            "description": "Free format ID used for metrics correlation by some agents",
                                            "type": ["string", "null"],
                                            "maxLength": 1024
                                        }
                                    }
                                },
                                "name": {
                                    "description": "Immutable name of the service emitting this event",
                                    "type": [
                                        "string",
                                        "null"
                                    ],
                                    "pattern": "^[a-zA-Z0-9 _-]+$",
                                    "maxLength": 1024
                                }
                            }
                        }
                    }
                },
                "duration": {
                    "type": "number",
                    "description": "Duration of the span in milliseconds"
                },
                "name": {
                    "type": "string",
                    "description": "Generic designation of a span in the scope of a transaction",
                    "maxLength": 1024
                },
                "stacktrace": {
                    "type": ["array", "null"],
                    "description": "List of stack frames with variable attributes (eg: lineno, filename, etc)",
                    "items": {
                        "$ref": "../stacktrace_frame.json"
                    },
                    "minItems": 0
                },
                "sync": {
                    "type": ["boolean", "null"],
                    "description": "Indicates whether the span was executed synchronously or asynchronously."
                }
            },
            "required": ["duration", "name", "type", "id","trace_id", "parent_id"]
        },
        { "anyOf":[
                {"required": ["timestamp"], "properties": {"timestamp": { "type": "integer" }}},
                {"required": ["start"], "properties": {"start": { "type": "number" }}}
            ]
        }
    ]
}