path: root/vendor/cloud.google.com/go/internal/trace/trace.go

// Copyright 2018 Google LLC
//
// 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.

package trace

import (
    "context"

    "go.opencensus.io/trace"
    "google.golang.org/api/googleapi"
    "google.golang.org/genproto/googleapis/rpc/code"
    "google.golang.org/grpc/status"
)

// StartSpan adds a span to the trace with the given name.
func StartSpan(ctx context.Context, name string) context.Context {
    ctx, _ = trace.StartSpan(ctx, name)
    return ctx
}

// EndSpan ends a span with the given error.
func EndSpan(ctx context.Context, err error) {
    span := trace.FromContext(ctx)
    if err != nil {
        span.SetStatus(toStatus(err))
    }
    span.End()
}

// ToStatus interrogates an error and converts it to an appropriate
// OpenCensus status.
func toStatus(err error) trace.Status {
    if err2, ok := err.(*googleapi.Error); ok {
        return trace.Status{Code: httpStatusCodeToOCCode(err2.Code), Message: err2.Message}
    } else if s, ok := status.FromError(err); ok {
        return trace.Status{Code: int32(s.Code()), Message: s.Message()}
    } else {
        return trace.Status{Code: int32(code.Code_UNKNOWN), Message: err.Error()}
    }
}

// TODO (deklerk): switch to using OpenCensus function when it becomes available.
// Reference: https://github.com/googleapis/googleapis/blob/26b634d2724ac5dd30ae0b0cbfb01f07f2e4050e/google/rpc/code.proto
func httpStatusCodeToOCCode(httpStatusCode int) int32 {
    switch httpStatusCode {
    case 200:
        return int32(code.Code_OK)
    case 499:
        return int32(code.Code_CANCELLED)
    case 500:
        return int32(code.Code_UNKNOWN) // Could also be Code_INTERNAL, Code_DATA_LOSS
    case 400:
        return int32(code.Code_INVALID_ARGUMENT) // Could also be Code_OUT_OF_RANGE
    case 504:
        return int32(code.Code_DEADLINE_EXCEEDED)
    case 404:
        return int32(code.Code_NOT_FOUND)
    case 409:
        return int32(code.Code_ALREADY_EXISTS) // Could also be Code_ABORTED
    case 403:
        return int32(code.Code_PERMISSION_DENIED)
    case 401:
        return int32(code.Code_UNAUTHENTICATED)
    case 429:
        return int32(code.Code_RESOURCE_EXHAUSTED)
    case 501:
        return int32(code.Code_UNIMPLEMENTED)
    case 503:
        return int32(code.Code_UNAVAILABLE)
    default:
        return int32(code.Code_UNKNOWN)
    }
}