73 lines
2.1 KiB
Go
73 lines
2.1 KiB
Go
package main
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import (
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"context"
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"fmt"
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"net/http"
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"time"
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"github.com/go-logr/logr"
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kedanet "github.com/kedacore/http-add-on/pkg/net"
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"github.com/kedacore/http-add-on/pkg/routing"
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)
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func moreThanPtr(i *int32, target int32) bool {
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return i != nil && *i > target
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}
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// newForwardingHandler takes in the service URL for the app backend
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// and forwards incoming requests to it. Note that it isn't multitenant.
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// It's intended to be deployed and scaled alongside the application itself.
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//
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// fwdSvcURL must have a valid scheme in it. The best way to do this is
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// create a URL with url.Parse("https://...")
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func newForwardingHandler(
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lggr logr.Logger,
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routingTable *routing.Table,
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dialCtxFunc kedanet.DialContextFunc,
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waitFunc forwardWaitFunc,
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waitTimeout time.Duration,
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respHeaderTimeout time.Duration,
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) http.Handler {
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roundTripper := &http.Transport{
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Proxy: http.ProxyFromEnvironment,
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DialContext: dialCtxFunc,
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ForceAttemptHTTP2: true,
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MaxIdleConns: 100,
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IdleConnTimeout: 90 * time.Second,
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TLSHandshakeTimeout: 10 * time.Second,
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ExpectContinueTimeout: 1 * time.Second,
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ResponseHeaderTimeout: respHeaderTimeout,
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}
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return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
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host, err := getHost(r)
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if err != nil {
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w.WriteHeader(400)
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w.Write([]byte("Host not found in request"))
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return
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}
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routingTarget, err := routingTable.Lookup(host)
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if err != nil {
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w.WriteHeader(404)
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w.Write([]byte(fmt.Sprintf("Host %s not found", r.Host)))
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return
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}
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ctx, done := context.WithTimeout(r.Context(), waitTimeout)
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defer done()
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if err := waitFunc(ctx, routingTarget.Deployment); err != nil {
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lggr.Error(err, "wait function failed, not forwarding request")
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w.WriteHeader(502)
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w.Write([]byte(fmt.Sprintf("error on backend (%s)", err)))
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return
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}
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targetSvcURL, err := routingTarget.ServiceURL()
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if err != nil {
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lggr.Error(err, "forwarding failed")
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w.WriteHeader(500)
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w.Write([]byte("error getting backend service URL"))
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return
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}
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forwardRequest(w, r, roundTripper, targetSvcURL)
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})
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}
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