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- extracting this package means it can be used in other components such as the asynchronous nats-queue-worker which may need to invoke functions which are scaled down to zero replicas. Ref: https://github.com/openfaas/nats-queue-worker/issues/32 Tested on Docker Swarm for scaling up, already scaled and not found error. Signed-off-by: Alex Ellis (VMware) <alexellis2@gmail.com>
54 lines
1.5 KiB
Go
54 lines
1.5 KiB
Go
// Copyright (c) OpenFaaS Author(s). 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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"github.com/openfaas/faas/gateway/scaling"
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)
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// MakeScalingHandler creates handler which can scale a function from
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// zero to N replica(s). After scaling the next http.HandlerFunc will
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// be called. If the function is not ready after the configured
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// amount of attempts / queries then next will not be invoked and a status
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// will be returned to the client.
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func MakeScalingHandler(next http.HandlerFunc, config scaling.ScalingConfig) http.HandlerFunc {
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scaler := scaling.NewFunctionScaler(config)
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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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res := scaler.Scale(functionName)
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if !res.Found {
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errStr := fmt.Sprintf("error finding function %s: %s", functionName, res.Error.Error())
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log.Printf("Scaling: %s", errStr)
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w.WriteHeader(http.StatusNotFound)
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w.Write([]byte(errStr))
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return
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}
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if res.Error != nil {
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errStr := fmt.Sprintf("error finding function %s: %s", functionName, res.Error.Error())
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log.Printf("Scaling: %s", 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 res.Available {
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next.ServeHTTP(w, r)
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return
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}
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log.Printf("[Scale] function=%s 0=>N timed-out after %f seconds", functionName, res.Duration.Seconds())
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}
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}
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