| // Copyright 2019 The Go Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| package export |
| |
| import ( |
| "context" |
| |
| "golang.org/x/tools/internal/telemetry/event" |
| ) |
| |
| // Tag manipulates the context using the event. |
| // If the event is type IsTag or IsStartSpan then it returns a context updated |
| // with tag values from the event. |
| // For all other event types the event tags will be updated with values from the |
| // context if they are missing. |
| func Tag(ctx context.Context, ev event.Event) (context.Context, event.Event) { |
| //TODO: Do we need to do something more efficient than just store tags |
| //TODO: directly on the context? |
| switch { |
| case ev.IsLabel(), ev.IsStartSpan(): |
| for i := ev.Tags.Iterator(); i.Next(); { |
| tag := i.Value() |
| ctx = context.WithValue(ctx, tag.Key(), tag.Value()) |
| } |
| default: |
| // all other types want the tags filled in if needed |
| for i := ev.Tags.Iterator(); i.Next(); { |
| tag := i.Value() |
| if tag.Value() == nil { |
| key := tag.Key() |
| i.Set(key.OfValue(ctx.Value(key.Identity()))) |
| } |
| } |
| } |
| return ctx, ev |
| } |