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Diffstat (limited to 'vendor/go.opencensus.io/tag/map.go')
-rw-r--r-- | vendor/go.opencensus.io/tag/map.go | 197 |
1 files changed, 197 insertions, 0 deletions
diff --git a/vendor/go.opencensus.io/tag/map.go b/vendor/go.opencensus.io/tag/map.go new file mode 100644 index 000000000..5b72ba6ad --- /dev/null +++ b/vendor/go.opencensus.io/tag/map.go @@ -0,0 +1,197 @@ +// Copyright 2017, OpenCensus 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. +// + +package tag + +import ( + "bytes" + "context" + "fmt" + "sort" +) + +// Tag is a key value pair that can be propagated on wire. +type Tag struct { + Key Key + Value string +} + +// Map is a map of tags. Use New to create a context containing +// a new Map. +type Map struct { + m map[Key]string +} + +// Value returns the value for the key if a value for the key exists. +func (m *Map) Value(k Key) (string, bool) { + if m == nil { + return "", false + } + v, ok := m.m[k] + return v, ok +} + +func (m *Map) String() string { + if m == nil { + return "nil" + } + keys := make([]Key, 0, len(m.m)) + for k := range m.m { + keys = append(keys, k) + } + sort.Slice(keys, func(i, j int) bool { return keys[i].Name() < keys[j].Name() }) + + var buffer bytes.Buffer + buffer.WriteString("{ ") + for _, k := range keys { + buffer.WriteString(fmt.Sprintf("{%v %v}", k.name, m.m[k])) + } + buffer.WriteString(" }") + return buffer.String() +} + +func (m *Map) insert(k Key, v string) { + if _, ok := m.m[k]; ok { + return + } + m.m[k] = v +} + +func (m *Map) update(k Key, v string) { + if _, ok := m.m[k]; ok { + m.m[k] = v + } +} + +func (m *Map) upsert(k Key, v string) { + m.m[k] = v +} + +func (m *Map) delete(k Key) { + delete(m.m, k) +} + +func newMap() *Map { + return &Map{m: make(map[Key]string)} +} + +// Mutator modifies a tag map. +type Mutator interface { + Mutate(t *Map) (*Map, error) +} + +// Insert returns a mutator that inserts a +// value associated with k. If k already exists in the tag map, +// mutator doesn't update the value. +func Insert(k Key, v string) Mutator { + return &mutator{ + fn: func(m *Map) (*Map, error) { + if !checkValue(v) { + return nil, errInvalidValue + } + m.insert(k, v) + return m, nil + }, + } +} + +// Update returns a mutator that updates the +// value of the tag associated with k with v. If k doesn't +// exists in the tag map, the mutator doesn't insert the value. +func Update(k Key, v string) Mutator { + return &mutator{ + fn: func(m *Map) (*Map, error) { + if !checkValue(v) { + return nil, errInvalidValue + } + m.update(k, v) + return m, nil + }, + } +} + +// Upsert returns a mutator that upserts the +// value of the tag associated with k with v. It inserts the +// value if k doesn't exist already. It mutates the value +// if k already exists. +func Upsert(k Key, v string) Mutator { + return &mutator{ + fn: func(m *Map) (*Map, error) { + if !checkValue(v) { + return nil, errInvalidValue + } + m.upsert(k, v) + return m, nil + }, + } +} + +// Delete returns a mutator that deletes +// the value associated with k. +func Delete(k Key) Mutator { + return &mutator{ + fn: func(m *Map) (*Map, error) { + m.delete(k) + return m, nil + }, + } +} + +// New returns a new context that contains a tag map +// originated from the incoming context and modified +// with the provided mutators. +func New(ctx context.Context, mutator ...Mutator) (context.Context, error) { + m := newMap() + orig := FromContext(ctx) + if orig != nil { + for k, v := range orig.m { + if !checkKeyName(k.Name()) { + return ctx, fmt.Errorf("key:%q: %v", k, errInvalidKeyName) + } + if !checkValue(v) { + return ctx, fmt.Errorf("key:%q value:%q: %v", k.Name(), v, errInvalidValue) + } + m.insert(k, v) + } + } + var err error + for _, mod := range mutator { + m, err = mod.Mutate(m) + if err != nil { + return ctx, err + } + } + return NewContext(ctx, m), nil +} + +// Do is similar to pprof.Do: a convenience for installing the tags +// from the context as Go profiler labels. This allows you to +// correlated runtime profiling with stats. +// +// It converts the key/values from the given map to Go profiler labels +// and calls pprof.Do. +// +// Do is going to do nothing if your Go version is below 1.9. +func Do(ctx context.Context, f func(ctx context.Context)) { + do(ctx, f) +} + +type mutator struct { + fn func(t *Map) (*Map, error) +} + +func (m *mutator) Mutate(t *Map) (*Map, error) { + return m.fn(t) +} |