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59 lines
1.9 KiB
59 lines
1.9 KiB
// Copyright 2016 Google Inc. All Rights Reserved. |
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// |
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// Licensed under the Apache License, Version 2.0 (the "License"); |
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// you may not use this file except in compliance with the License. |
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// You may obtain a copy of the License at |
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// |
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// http://www.apache.org/licenses/LICENSE-2.0 |
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// |
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// Unless required by applicable law or agreed to in writing, software |
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// distributed under the License is distributed on an "AS IS" BASIS, |
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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// See the License for the specific language governing permissions and |
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// limitations under the License. |
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package internal |
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import ( |
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"errors" |
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"google.golang.org/grpc/naming" |
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) |
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// PoolResolver provides a fixed list of addresses to load balance between |
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// and does not provide further updates. |
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type PoolResolver struct { |
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poolSize int |
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dialOpt *DialSettings |
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ch chan []*naming.Update |
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} |
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// NewPoolResolver returns a PoolResolver |
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// This is an EXPERIMENTAL API and may be changed or removed in the future. |
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func NewPoolResolver(size int, o *DialSettings) *PoolResolver { |
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return &PoolResolver{poolSize: size, dialOpt: o} |
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} |
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// Resolve returns a Watcher for the endpoint defined by the DialSettings |
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// provided to NewPoolResolver. |
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func (r *PoolResolver) Resolve(target string) (naming.Watcher, error) { |
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if r.dialOpt.Endpoint == "" { |
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return nil, errors.New("No endpoint configured") |
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} |
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addrs := make([]*naming.Update, 0, r.poolSize) |
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for i := 0; i < r.poolSize; i++ { |
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addrs = append(addrs, &naming.Update{Op: naming.Add, Addr: r.dialOpt.Endpoint, Metadata: i}) |
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} |
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r.ch = make(chan []*naming.Update, 1) |
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r.ch <- addrs |
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return r, nil |
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} |
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// Next returns a static list of updates on the first call, |
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// and blocks indefinitely until Close is called on subsequent calls. |
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func (r *PoolResolver) Next() ([]*naming.Update, error) { |
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return <-r.ch, nil |
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} |
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func (r *PoolResolver) Close() { |
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close(r.ch) |
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}
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