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https://github.com/caddyserver/caddy.git
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86 lines
2.2 KiB
Go
Executable file
86 lines
2.2 KiB
Go
Executable file
// Copyright 2015 Matthew Holt and The Caddy Authors
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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 reverseproxy
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import (
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"net/http"
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"time"
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)
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// Upstream represents the interface that must be satisfied to use the healthchecker.
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type Upstream interface {
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SetHealthiness(bool)
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}
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// HealthChecker represents a worker that periodically evaluates if proxy upstream host is healthy.
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type HealthChecker struct {
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upstream Upstream
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Ticker *time.Ticker
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HTTPClient *http.Client
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StopChan chan bool
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}
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// ScheduleChecks periodically runs health checks against an upstream host.
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func (h *HealthChecker) ScheduleChecks(url string) {
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// check if a host is healthy on start vs waiting for timer
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h.upstream.SetHealthiness(h.IsHealthy(url))
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stop := make(chan bool)
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h.StopChan = stop
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go func() {
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for {
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select {
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case <-h.Ticker.C:
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h.upstream.SetHealthiness(h.IsHealthy(url))
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case <-stop:
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return
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}
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}
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}()
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}
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// Stop stops the healthchecker from makeing further requests.
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func (h *HealthChecker) Stop() {
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h.Ticker.Stop()
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close(h.StopChan)
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}
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// IsHealthy attempts to check if a upstream host is healthy.
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func (h *HealthChecker) IsHealthy(url string) bool {
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req, err := http.NewRequest(http.MethodGet, url, nil)
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if err != nil {
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return false
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}
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resp, err := h.HTTPClient.Do(req)
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if err != nil {
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return false
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}
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if resp.StatusCode < 200 || resp.StatusCode >= 400 {
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return false
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}
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return true
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}
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// NewHealthCheckWorker returns a new instance of a HealthChecker.
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func NewHealthCheckWorker(u Upstream, interval time.Duration, client *http.Client) *HealthChecker {
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return &HealthChecker{
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upstream: u,
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Ticker: time.NewTicker(interval),
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HTTPClient: client,
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}
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}
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