// Copyright 2019, OpenTelemetry Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

syntax = "proto3";

package opentelemetry;

option csharp_namespace = "OpenTelemetry.Proto.Common.V1";
option java_multiple_files = true;
option java_package = "io.opentelemetry.proto.common.v1";
option java_outer_classname = "CommonProto";
option go_package = "opentelemetry/pb";

// AnyValue is used to represent any type of attribute value. AnyValue may contain a
// primitive value such as a string or integer or it may contain an arbitrary nested
// object containing arrays, key-value lists and primitives.
message AnyValue {
  // The value is one of the listed fields. It is valid for all values to be unspecified
  // in which case this AnyValue is considered to be "empty".
  oneof value {
    string string_value = 1;
    bool bool_value = 2;
    int64 int_value = 3;
    double double_value = 4;
    ArrayValue array_value = 5;
    KeyValueList kvlist_value = 6;
    bytes bytes_value = 7;
  }
}

// ArrayValue is a list of AnyValue messages. We need ArrayValue as a message
// since oneof in AnyValue does not allow repeated fields.
message ArrayValue {
  // Array of values. The array may be empty (contain 0 elements).
  repeated AnyValue values = 1;
}

// KeyValueList is a list of KeyValue messages. We need KeyValueList as a message
// since `oneof` in AnyValue does not allow repeated fields. Everywhere else where we need
// a list of KeyValue messages (e.g. in Span) we use `repeated KeyValue` directly to
// avoid unnecessary extra wrapping (which slows down the protocol). The 2 approaches
// are semantically equivalent.
message KeyValueList {
  // A collection of key/value pairs of key-value pairs. The list may be empty (may
  // contain 0 elements).
  // The keys MUST be unique (it is not allowed to have more than one
  // value with the same key).
  repeated KeyValue values = 1;
}

// KeyValue is a key-value pair that is used to store Span attributes, Link
// attributes, etc.
message KeyValue {
  string key = 1;
  AnyValue value = 2;
}