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9512f09d2b
Existing code has been used for scaling up and querying replicas. This meant the new code was deleted and there is less duplication now. The cache store a whole query response rather than just the available replica count and the tests were updated. This has been tested with Docker swarm and the image: openfaas/gateway:scale-17-07-2018 This feature now needs the env-var of scale_from_zero to be enabled in order to turn on the scaling behaviour. Signed-off-by: Alex Ellis (VMware) <alexellis2@gmail.com>
91 lines
2.3 KiB
Go
91 lines
2.3 KiB
Go
// Copyright (c) OpenFaaS Project. All rights reserved.
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// Licensed under the MIT license. See LICENSE file in the project root for full license information.
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package handlers
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import (
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"fmt"
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"log"
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"net/http"
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"time"
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)
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// ScalingConfig for scaling behaviours
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type ScalingConfig struct {
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MaxPollCount uint
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FunctionPollInterval time.Duration
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CacheExpiry time.Duration
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ServiceQuery ServiceQuery
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}
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// MakeScalingHandler creates handler which can scale a function from
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// zero to 1 replica(s).
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func MakeScalingHandler(next http.HandlerFunc, upstream http.HandlerFunc, config ScalingConfig) http.HandlerFunc {
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cache := FunctionCache{
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Cache: make(map[string]*FunctionMeta),
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Expiry: config.CacheExpiry,
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}
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return func(w http.ResponseWriter, r *http.Request) {
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functionName := getServiceName(r.URL.String())
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if serviceQueryResponse, hit := cache.Get(functionName); hit && serviceQueryResponse.AvailableReplicas > 0 {
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next.ServeHTTP(w, r)
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return
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}
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queryResponse, err := config.ServiceQuery.GetReplicas(functionName)
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cache.Set(functionName, queryResponse)
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if err != nil {
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var errStr string
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errStr = fmt.Sprintf("error finding function %s: %s", functionName, err.Error())
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log.Printf(errStr)
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w.WriteHeader(http.StatusInternalServerError)
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w.Write([]byte(errStr))
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return
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}
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if queryResponse.AvailableReplicas == 0 {
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minReplicas := uint64(1)
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if queryResponse.MinReplicas > 0 {
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minReplicas = queryResponse.MinReplicas
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}
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err := config.ServiceQuery.SetReplicas(functionName, minReplicas)
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if err != nil {
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errStr := fmt.Errorf("unable to scale function [%s], err: %s", functionName, err)
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log.Printf(errStr.Error())
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w.WriteHeader(http.StatusInternalServerError)
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w.Write([]byte(errStr.Error()))
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return
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}
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for i := 0; i < int(config.MaxPollCount); i++ {
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queryResponse, err := config.ServiceQuery.GetReplicas(functionName)
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cache.Set(functionName, queryResponse)
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if err != nil {
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errStr := fmt.Sprintf("error: %s", err.Error())
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log.Printf(errStr)
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w.WriteHeader(http.StatusInternalServerError)
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w.Write([]byte(errStr))
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return
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}
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if queryResponse.AvailableReplicas > 0 {
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break
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}
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time.Sleep(config.FunctionPollInterval)
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}
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}
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next.ServeHTTP(w, r)
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}
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}
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