# Copyright (c) 2017-2022 Cloudflare, Inc.
# Licensed under the Apache 2.0 license found in the LICENSE file or at:
#     https://opensource.org/licenses/Apache-2.0

@0xc40f73be329a38d9;

using Cxx = import "/capnp/c++.capnp";
$Cxx.namespace("workerd::rpc");

# This file contains trace helper structures. The Trace struct is deliberately not defined here –
# many files just need to have the span/tag definitions available. Since Trace contains interfaces,
# it also causes a large amount of code to be generated in the .capnp.h file, which affects header
# parsing overhead/compile times for every file that depends on the capnp file defining Trace.

# The value of a span tag.
struct TagValue {
  union {
    string @0 :Text;
    bool @1 :Bool;
    int64 @2 :Int64;
    float64 @3 :Float64;
  }
}

# A key/value span tag for tracing.
struct Tag {
  key @0 :Text;
  value @1 :TagValue;
}

struct UserSpanData {
  # Representation of a completed user span
  operationName @0 :Text;

  startTimeNs @1 :Int64;
  endTimeNs @2 :Int64;
  # Nanoseconds since Unix epoch

  tags @3 :List(Tag);

  spanId @4 :UInt64;
  parentSpanId @5 :UInt64;
}

struct SpanOpenData {
  # Representation of a SpanOpen event, created when a user span is opened.
  operationName @0 :Text;

  startTimeNs @1 :Int64;
  # Nanoseconds since Unix epoch

  spanId @2 :UInt64;
  parentSpanId @3 :UInt64;
}

struct SpanEndData {
  # Representation of an event that indicates completion of a user span. This information is
  # provided to the streaming tail worker in the Attributes and SpanClose events.

  endTimeNs @0 :Int64;
  # Nanoseconds since Unix epoch

  # List of span attributes
  tags @1 :List(Tag);
  spanId @2 :UInt64;
}