// 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.proto.trace.v1;

import "./common.proto";
import "./resource.proto";

option csharp_namespace = "OpenTelemetry.Proto.Trace.V1";
option java_multiple_files = true;
option java_package = "io.opentelemetry.proto.trace.v1";
option java_outer_classname = "TraceProto";
option go_package = "go.opentelemetry.io/proto/otlp/trace/v1";

// TracesData represents the traces data that can be stored in a persistent storage,
// OR can be embedded by other protocols that transfer OTLP traces data but do
// not implement the OTLP protocol.
//
// The main difference between this message and collector protocol is that
// in this message there will not be any "control" or "metadata" specific to
// OTLP protocol.
//
// When new fields are added into this message, the OTLP request MUST be updated
// as well.
message TracesData {
  // An array of ResourceSpans.
  // For data coming from a single resource this array will typically contain
  // one element. Intermediary nodes that receive data from multiple origins
  // typically batch the data before forwarding further and in that case this
  // array will contain multiple elements.
  repeated ResourceSpans resource_spans = 1;
}

// A collection of ScopeSpans from a Resource.
message ResourceSpans {
  reserved 1000;

  // The resource for the spans in this message.
  // If this field is not set then no resource info is known.
  opentelemetry.proto.resource.v1.Resource resource = 1;

  // A list of ScopeSpans that originate from a resource.
  repeated ScopeSpans scope_spans = 2;

  // The Schema URL, if known. This is the identifier of the Schema that the resource data
  // is recorded in. To learn more about Schema URL see
  // https://opentelemetry.io/docs/specs/otel/schemas/#schema-url
  // This schema_url applies to the data in the "resource" field. It does not apply
  // to the data in the "scope_spans" field which have their own schema_url field.
  string schema_url = 3;
}

// A collection of Spans produced by an InstrumentationScope.
message ScopeSpans {
  // The instrumentation scope information for the spans in this message.
  // Semantically when InstrumentationScope isn't set, it is equivalent with
  // an empty instrumentation scope name (unknown).
  opentelemetry.proto.common.v1.InstrumentationScope scope = 1;

  // A list of Spans that originate from an instrumentation scope.
  repeated Span spans = 2;

  // The Schema URL, if known. This is the identifier of the Schema that the span data
  // is recorded in. To learn more about Schema URL see
  // https://opentelemetry.io/docs/specs/otel/schemas/#schema-url
  // This schema_url applies to all spans and span events in the "spans" field.
  string schema_url = 3;
}

// A Span represents a single operation performed by a single component of the system.
//
// The next available field id is 17.
message Span {
  // A unique identifier for a trace. All spans from the same trace share
  // the same `trace_id`. The ID is a 16-byte array. An ID with all zeroes OR
  // of length other than 16 bytes is considered invalid (empty string in OTLP/JSON
  // is zero-length and thus is also invalid).
  //
  // This field is required.
  bytes trace_id = 1;

  // A unique identifier for a span within a trace, assigned when the span
  // is created. The ID is an 8-byte array. An ID with all zeroes OR of length
  // other than 8 bytes is considered invalid (empty string in OTLP/JSON
  // is zero-length and thus is also invalid).
  //
  // This field is required.
  bytes span_id = 2;

  // trace_state conveys information about request position in multiple distributed tracing graphs.
  // It is a trace_state in w3c-trace-context format: https://www.w3.org/TR/trace-context/#tracestate-header
  // See also https://github.com/w3c/distributed-tracing for more details about this field.
  string trace_state = 3;

  // The `span_id` of this span's parent span. If this is a root span, then this
  // field must be empty. The ID is an 8-byte array.
  bytes parent_span_id = 4;

  // Flags, a bit field. 8 least significant bits are the trace
  // flags as defined in W3C Trace Context specification. Readers
  // MUST not assume that 24 most significant bits will be zero.
  // To read the 8-bit W3C trace flag, use `flags & SPAN_FLAGS_TRACE_FLAGS_MASK`.
  //
  // When creating span messages, if the message is logically forwarded from another source
  // with an equivalent flags fields (i.e., usually another OTLP span message), the field SHOULD
  // be copied as-is. If creating from a source that does not have an equivalent flags field
  // (such as a runtime representation of an OpenTelemetry span), the high 24 bits MUST
  // be set to zero.
  //
  // [Optional].
  //
  // See https://www.w3.org/TR/trace-context-2/#trace-flags for the flag definitions.
  fixed32 flags = 16;

  // A description of the span's operation.
  //
  // For example, the name can be a qualified method name or a file name
  // and a line number where the operation is called. A best practice is to use
  // the same display name at the same call point in an application.
  // This makes it easier to correlate spans in different traces.
  //
  // This field is semantically required to be set to non-empty string.
  // Empty value is equivalent to an unknown span name.
  //
  // This field is required.
  string name = 5;

  // SpanKind is the type of span. Can be used to specify additional relationships between spans
  // in addition to a parent/child relationship.
  enum SpanKind {
    // Unspecified. Do NOT use as default.
    // Implementations MAY assume SpanKind to be INTERNAL when receiving UNSPECIFIED.
    SPAN_KIND_UNSPECIFIED = 0;

    // Indicates that the span represents an internal operation within an application,
    // as opposed to an operation happening at the boundaries. Default value.
    SPAN_KIND_INTERNAL = 1;

    // Indicates that the span covers server-side handling of an RPC or other
    // remote network request.
    SPAN_KIND_SERVER = 2;

    // Indicates that the span describes a request to some remote service.
    SPAN_KIND_CLIENT = 3;

    // Indicates that the span describes a producer sending a message to a broker.
    // Unlike CLIENT and SERVER, there is often no direct critical path latency relationship
    // between producer and consumer spans. A PRODUCER span ends when the message was accepted
    // by the broker while the logical processing of the message might span a much longer time.
    SPAN_KIND_PRODUCER = 4;

    // Indicates that the span describes consumer receiving a message from a broker.
    // Like the PRODUCER kind, there is often no direct critical path latency relationship
    // between producer and consumer spans.
    SPAN_KIND_CONSUMER = 5;
  }

  // Distinguishes between spans generated in a particular context. For example,
  // two spans with the same name may be distinguished using `CLIENT` (caller)
  // and `SERVER` (callee) to identify queueing latency associated with the span.
  SpanKind kind = 6;

  // start_time_unix_nano is the start time of the span. On the client side, this is the time
  // kept by the local machine where the span execution starts. On the server side, this
  // is the time when the server's application handler starts running.
  // Value is UNIX Epoch time in nanoseconds since 00:00:00 UTC on 1 January 1970.
  //
  // This field is semantically required and it is expected that end_time >= start_time.
  fixed64 start_time_unix_nano = 7;

  // end_time_unix_nano is the end time of the span. On the client side, this is the time
  // kept by the local machine where the span execution ends. On the server side, this
  // is the time when the server application handler stops running.
  // Value is UNIX Epoch time in nanoseconds since 00:00:00 UTC on 1 January 1970.
  //
  // This field is semantically required and it is expected that end_time >= start_time.
  fixed64 end_time_unix_nano = 8;

  // attributes is a collection of key/value pairs. Note, global attributes
  // like server name can be set using the resource API. Examples of attributes:
  //
  //     "/http/user_agent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_2) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/71.0.3578.98 Safari/537.36"
  //     "/http/server_latency": 300
  //     "example.com/myattribute": true
  //     "example.com/score": 10.239
  //
  // The OpenTelemetry API specification further restricts the allowed value types:
  // https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/common/README.md#attribute
  // Attribute keys MUST be unique (it is not allowed to have more than one
  // attribute with the same key).
  repeated opentelemetry.proto.common.v1.KeyValue attributes = 9;

  // dropped_attributes_count is the number of attributes that were discarded. Attributes
  // can be discarded because their keys are too long or because there are too many
  // attributes. If this value is 0, then no attributes were dropped.
  uint32 dropped_attributes_count = 10;

  // Event is a time-stamped annotation of the span, consisting of user-supplied
  // text description and key-value pairs.
  message Event {
    // time_unix_nano is the time the event occurred.
    fixed64 time_unix_nano = 1;

    // name of the event.
    // This field is semantically required to be set to non-empty string.
    string name = 2;

    // attributes is a collection of attribute key/value pairs on the event.
    // Attribute keys MUST be unique (it is not allowed to have more than one
    // attribute with the same key).
    repeated opentelemetry.proto.common.v1.KeyValue attributes = 3;

    // dropped_attributes_count is the number of dropped attributes. If the value is 0,
    // then no attributes were dropped.
    uint32 dropped_attributes_count = 4;
  }

  // events is a collection of Event items.
  repeated Event events = 11;

  // dropped_events_count is the number of dropped events. If the value is 0, then no
  // events were dropped.
  uint32 dropped_events_count = 12;

  // A pointer from the current span to another span in the same trace or in a
  // different trace. For example, this can be used in batching operations,
  // where a single batch handler processes multiple requests from different
  // traces or when the handler receives a request from a different project.
  message Link {
    // A unique identifier of a trace that this linked span is part of. The ID is a
    // 16-byte array.
    bytes trace_id = 1;

    // A unique identifier for the linked span. The ID is an 8-byte array.
    bytes span_id = 2;

    // The trace_state associated with the link.
    string trace_state = 3;

    // attributes is a collection of attribute key/value pairs on the link.
    // Attribute keys MUST be unique (it is not allowed to have more than one
    // attribute with the same key).
    repeated opentelemetry.proto.common.v1.KeyValue attributes = 4;

    // dropped_attributes_count is the number of dropped attributes. If the value is 0,
    // then no attributes were dropped.
    uint32 dropped_attributes_count = 5;

    // Flags, a bit field. 8 least significant bits are the trace
    // flags as defined in W3C Trace Context specification. Readers
    // MUST not assume that 24 most significant bits will be zero.
    // When creating new spans, the most-significant 24-bits MUST be
    // zero.  To read the 8-bit W3C trace flag (use flags &
    // SPAN_FLAGS_TRACE_FLAGS_MASK).  [Optional].
    //
    // See https://www.w3.org/TR/trace-context-2/#trace-flags for the flag definitions.
    fixed32 flags = 6;
  }

  // links is a collection of Links, which are references from this span to a span
  // in the same or different trace.
  repeated Link links = 13;

  // dropped_links_count is the number of dropped links after the maximum size was
  // enforced. If this value is 0, then no links were dropped.
  uint32 dropped_links_count = 14;

  // An optional final status for this span. Semantically when Status isn't set, it means
  // span's status code is unset, i.e. assume STATUS_CODE_UNSET (code = 0).
  Status status = 15;
}

// The Status type defines a logical error model that is suitable for different
// programming environments, including REST APIs and RPC APIs.
message Status {
  reserved 1;

  // A developer-facing human readable error message.
  string message = 2;

  // For the semantics of status codes see
  // https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/trace/api.md#set-status
  enum StatusCode {
    // The default status.
    STATUS_CODE_UNSET               = 0;
    // The Span has been validated by an Application developer or Operator to 
    // have completed successfully.
    STATUS_CODE_OK                  = 1;
    // The Span contains an error.
    STATUS_CODE_ERROR               = 2;
  };

  // The status code.
  StatusCode code = 3;
}

// SpanFlags represents constants used to interpret the
// Span.flags field, which is protobuf 'fixed32' type and is to
// be used as bit-fields. Each non-zero value defined in this enum is
// a bit-mask.  To extract the bit-field, for example, use an
// expression like:
//
//   (span.flags & SPAN_FLAGS_TRACE_FLAGS_MASK)
//
// See https://www.w3.org/TR/trace-context-2/#trace-flags for the flag definitions.
//
// Note that Span flags were introduced in version 1.1 of the
// OpenTelemetry protocol.  Older Span producers do not set this
// field, consequently consumers should not rely on the absence of a
// particular flag bit to indicate the presence of a particular feature.
enum SpanFlags {
  // The zero value for the enum. Should not be used for comparisons.
  // Instead use bitwise "and" with the appropriate mask as shown above.
  SPAN_FLAGS_DO_NOT_USE = 0;

  // Bits 0-7 are used for trace flags.
  SPAN_FLAGS_TRACE_FLAGS_MASK = 0x000000FF;

  // Bits 8-31 are reserved for future use.
}