chore: import upstream snapshot with attribution

config/source/memory/README.md

@@ -0,0 +1,44 @@
+# Memory Source
+
+The memory source provides in-memory data as a source
+
+## Memory Format
+
+The expected data format is json
+
+```json
+data := []byte(`{
+    "hosts": {
+        "database": {
+            "address": "10.0.0.1",
+            "port": 3306
+        },
+        "cache": {
+            "address": "10.0.0.2",
+            "port": 6379
+        }
+    }
+}`)
+```
+
+## New Source
+
+Specify source with data
+
+```go
+memorySource := memory.NewSource(
+	memory.WithJSON(data),
+)
+```
+
+## Load Source
+
+Load the source into config
+
+```go
+// Create new config
+conf := config.NewConfig()
+
+// Load memory source
+conf.Load(memorySource)
+```

config/source/memory/memory.go

@@ -0,0 +1,99 @@
+// Package memory is a memory source
+package memory
+
+import (
+	"sync"
+	"time"
+
+	"github.com/google/uuid"
+	"go-micro.dev/v6/config/source"
+)
+
+type memory struct {
+	ChangeSet *source.ChangeSet
+	Watchers  map[string]*watcher
+	sync.RWMutex
+}
+
+func (s *memory) Read() (*source.ChangeSet, error) {
+	s.RLock()
+	cs := &source.ChangeSet{
+		Format:    s.ChangeSet.Format,
+		Timestamp: s.ChangeSet.Timestamp,
+		Data:      s.ChangeSet.Data,
+		Checksum:  s.ChangeSet.Checksum,
+		Source:    s.ChangeSet.Source,
+	}
+	s.RUnlock()
+	return cs, nil
+}
+
+func (s *memory) Watch() (source.Watcher, error) {
+	w := &watcher{
+		Id:      uuid.New().String(),
+		Updates: make(chan *source.ChangeSet, 100),
+		Source:  s,
+	}
+
+	s.Lock()
+	s.Watchers[w.Id] = w
+	s.Unlock()
+	return w, nil
+}
+
+func (s *memory) Write(cs *source.ChangeSet) error {
+	s.Update(cs)
+	return nil
+}
+
+// Update allows manual updates of the config data.
+func (s *memory) Update(c *source.ChangeSet) {
+	// don't process nil
+	if c == nil {
+		return
+	}
+
+	// hash the file
+	s.Lock()
+	// update changeset
+	s.ChangeSet = &source.ChangeSet{
+		Data:      c.Data,
+		Format:    c.Format,
+		Source:    "memory",
+		Timestamp: time.Now(),
+	}
+	s.ChangeSet.Checksum = s.ChangeSet.Sum()
+
+	// update watchers
+	for _, w := range s.Watchers {
+		select {
+		case w.Updates <- s.ChangeSet:
+		default:
+		}
+	}
+	s.Unlock()
+}
+
+func (s *memory) String() string {
+	return "memory"
+}
+
+func NewSource(opts ...source.Option) source.Source {
+	var options source.Options
+	for _, o := range opts {
+		o(&options)
+	}
+
+	s := &memory{
+		Watchers: make(map[string]*watcher),
+	}
+
+	if options.Context != nil {
+		c, ok := options.Context.Value(changeSetKey{}).(*source.ChangeSet)
+		if ok {
+			s.Update(c)
+		}
+	}
+
+	return s
+}

config/source/memory/options.go

@@ -0,0 +1,41 @@
+package memory
+
+import (
+	"context"
+
+	"go-micro.dev/v6/config/source"
+)
+
+type changeSetKey struct{}
+
+func withData(d []byte, f string) source.Option {
+	return func(o *source.Options) {
+		if o.Context == nil {
+			o.Context = context.Background()
+		}
+		o.Context = context.WithValue(o.Context, changeSetKey{}, &source.ChangeSet{
+			Data:   d,
+			Format: f,
+		})
+	}
+}
+
+// WithChangeSet allows a changeset to be set.
+func WithChangeSet(cs *source.ChangeSet) source.Option {
+	return func(o *source.Options) {
+		if o.Context == nil {
+			o.Context = context.Background()
+		}
+		o.Context = context.WithValue(o.Context, changeSetKey{}, cs)
+	}
+}
+
+// WithJSON allows the source data to be set to json.
+func WithJSON(d []byte) source.Option {
+	return withData(d, "json")
+}
+
+// WithYAML allows the source data to be set to yaml.
+func WithYAML(d []byte) source.Option {
+	return withData(d, "yaml")
+}

config/source/memory/watcher.go

@@ -0,0 +1,23 @@
+package memory
+
+import (
+	"go-micro.dev/v6/config/source"
+)
+
+type watcher struct {
+	Updates chan *source.ChangeSet
+	Source  *memory
+	Id      string
+}
+
+func (w *watcher) Next() (*source.ChangeSet, error) {
+	cs := <-w.Updates
+	return cs, nil
+}
+
+func (w *watcher) Stop() error {
+	w.Source.Lock()
+	delete(w.Source.Watchers, w.Id)
+	w.Source.Unlock()
+	return nil
+}