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88eea5f62e
Introduces a single-flight call to a function's health endpoint to verify that it is registered with an Istio sidecar (Envoy) before letting the invocation through. Results are cached for 5 seconds, before a probe is required again. Tested without Istio, with probe_functions environment variable set to true, I saw a probe execute in the logs. Fixes: #1721 for Istio users. Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alex@openfaas.com>
46 lines
1.2 KiB
Go
46 lines
1.2 KiB
Go
package handlers
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import (
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"fmt"
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"net/http"
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"golang.org/x/sync/singleflight"
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"github.com/openfaas/faas/gateway/pkg/middleware"
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"github.com/openfaas/faas/gateway/probing"
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)
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func MakeProbeHandler(prober probing.FunctionProber, cache probing.ProbeCacher, resolver middleware.BaseURLResolver, next http.HandlerFunc, defaultNamespace string) http.HandlerFunc {
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group := singleflight.Group{}
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return func(w http.ResponseWriter, r *http.Request) {
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functionName, namespace := middleware.GetNamespace(defaultNamespace, middleware.GetServiceName(r.URL.String()))
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key := fmt.Sprintf("Probe-%s.%s", functionName, namespace)
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res, _, _ := group.Do(key, func() (interface{}, error) {
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cached, hit := cache.Get(functionName, namespace)
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var probeResult probing.FunctionProbeResult
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if hit && cached != nil && cached.Available {
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probeResult = *cached
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} else {
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probeResult = prober.Probe(functionName, namespace)
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cache.Set(functionName, namespace, &probeResult)
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}
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return probeResult, nil
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})
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fnRes := res.(probing.FunctionProbeResult)
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if !fnRes.Available {
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http.Error(w, fmt.Sprintf("unable to probe function endpoint %s", fnRes.Error),
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http.StatusServiceUnavailable)
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return
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}
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next(w, r)
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}
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}
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