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- /*
- Copyright 2017 Google Inc.
- 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 client
- import (
- "fmt"
- log "github.com/golang/glog"
- "context"
- "notabug.org/themusicgod1/gnmi/ctree"
- )
- // Client adds a caching layer on top of a simple query client.
- //
- // It works similarly to BaseClient and adds the Leaves method to return
- // current tree state.
- type CacheClient struct {
- *BaseClient
- *ctree.Tree
- synced chan struct{}
- clientHandler NotificationHandler
- }
- var _ Client = &CacheClient{}
- // New returns an initialized caching client.
- func New() *CacheClient {
- c := &CacheClient{
- BaseClient: &BaseClient{},
- Tree: &ctree.Tree{},
- synced: make(chan struct{}),
- }
- return c
- }
- // Subscribe implements the Client interface.
- func (c *CacheClient) Subscribe(ctx context.Context, q Query, clientType ...string) error {
- q.ProtoHandler = nil
- if q.NotificationHandler != nil {
- c.clientHandler = q.NotificationHandler
- }
- q.NotificationHandler = c.defaultHandler
- return c.BaseClient.Subscribe(ctx, q, clientType...)
- }
- // defaultHandler is passed into the client specific implementations. It will
- // be called for each leaf notification generated by the client.
- func (c *CacheClient) defaultHandler(n Notification) error {
- switch v := n.(type) {
- default:
- return fmt.Errorf("invalid type %#v", v)
- case Connected: // Ignore.
- case Error:
- return fmt.Errorf("received error: %v", v)
- case Update:
- c.Add(v.Path, TreeVal{TS: v.TS, Val: v.Val})
- case Delete:
- c.Delete(v.Path)
- case Sync:
- select {
- default:
- close(c.synced)
- case <-c.synced:
- }
- }
- if c.clientHandler != nil {
- return c.clientHandler(n)
- }
- return nil
- }
- // Poll implements the Client interface.
- // Poll also closes the channel returned by Synced and resets it.
- func (c *CacheClient) Poll() error {
- select {
- default:
- close(c.synced)
- case <-c.synced:
- }
- return c.BaseClient.Poll()
- }
- // Synced will close when a sync is recieved from the query.
- func (c *CacheClient) Synced() <-chan struct{} {
- return c.synced
- }
- // Leaves returns the current state of the received tree. It's safe to call at
- // any point after New.
- func (c *CacheClient) Leaves() Leaves {
- // Convert node items into Leaf (expand TreeVal leaves).
- var pvs Leaves
- c.WalkSorted(func(path []string, _ *ctree.Leaf, value interface{}) {
- tv, ok := value.(TreeVal)
- if !ok {
- log.Errorf("Invalid value in tree: %s=%#v", path, value)
- return
- }
- pvs = append(pvs, Leaf{Path: path, Val: tv.Val, TS: tv.TS})
- })
- return pvs
- }
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