Soam Vasani
bbaa766fe1
If the pool is new or very busy, we may call the chosen container's specialize endpoint before it's actually up -- handle the case by retrying a few times. Also namespace-qualify service hostname (since router and functions run in different namespaces).
409 lines
11 KiB
Go
409 lines
11 KiB
Go
/*
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Copyright 2016 The Fission Authors.
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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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http://www.apache.org/licenses/LICENSE-2.0
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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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*/
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package poolmgr
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import (
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"bytes"
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"errors"
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"fmt"
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"log"
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"math/rand"
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"net"
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"net/http"
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"net/url"
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"time"
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"k8s.io/client-go/1.4/kubernetes"
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"k8s.io/client-go/1.4/pkg/api"
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"k8s.io/client-go/1.4/pkg/api/v1"
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"k8s.io/client-go/1.4/pkg/apis/extensions/v1beta1"
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"k8s.io/client-go/1.4/pkg/labels"
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"k8s.io/client-go/1.4/pkg/util/intstr"
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"github.com/platform9/fission"
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)
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type (
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GenericPool struct {
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env *fission.Environment
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replicas int32 // num containers
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deployment *v1beta1.Deployment // kubernetes deployment
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namespace string // namespace to keep our resources
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podReadyTimeout time.Duration // timeout for generic pods to become ready
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controllerUrl string
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kubernetesClient *kubernetes.Clientset
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requestChannel chan *choosePodRequest
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}
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// serialize the choosing of pods so that choices don't conflict
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choosePodRequest struct {
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newLabels map[string]string
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responseChannel chan *choosePodResponse
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}
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choosePodResponse struct {
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pod *v1.Pod
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error
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}
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)
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func MakeGenericPool(
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controllerUrl string,
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kubernetesClient *kubernetes.Clientset,
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env *fission.Environment,
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initialReplicas int32,
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namespace string) (*GenericPool, error) {
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log.Printf("Creating pool for environment %v", env.Metadata)
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gp := &GenericPool{
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env: env,
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replicas: initialReplicas,
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requestChannel: make(chan *choosePodRequest),
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kubernetesClient: kubernetesClient,
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namespace: namespace,
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podReadyTimeout: 5 * time.Minute,
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controllerUrl: controllerUrl,
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}
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// create the pool
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err := gp.createPool()
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if err != nil {
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return nil, err
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}
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// wait for at least one pod to be ready
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log.Printf("[%v] Deployment created, waiting for a ready pod", env.Metadata)
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err = gp.waitForReadyPod()
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if err != nil {
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return nil, err
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}
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go gp.choosePodService()
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return gp, nil
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}
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// choosePodService serializes the choosing of pods
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func (gp *GenericPool) choosePodService() {
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for {
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select {
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case req := <-gp.requestChannel:
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pod, err := gp._choosePod(req.newLabels)
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if err != nil {
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req.responseChannel <- &choosePodResponse{error: err}
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continue
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}
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req.responseChannel <- &choosePodResponse{pod: pod}
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}
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}
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}
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// choosePod picks a ready pod from the pool and relabels it, waiting if necessary.
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// returns the pod API object.
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func (gp *GenericPool) choosePod(newLabels map[string]string) (*v1.Pod, error) {
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req := &choosePodRequest{
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newLabels: newLabels,
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responseChannel: make(chan *choosePodResponse),
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}
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gp.requestChannel <- req
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resp := <-req.responseChannel
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return resp.pod, resp.error
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}
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// _choosePod is called serially by choosePodService
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func (gp *GenericPool) _choosePod(newLabels map[string]string) (*v1.Pod, error) {
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startTime := time.Now()
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for {
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// Retries took too long, error out.
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if time.Now().Sub(startTime) > gp.podReadyTimeout {
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log.Printf("[%v] Erroring out, timed out", newLabels)
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return nil, errors.New("timeout: waited too long to get a ready pod")
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}
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// Get pods; filter the ones that are ready
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podList, err := gp.kubernetesClient.Core().Pods(gp.namespace).List(
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api.ListOptions{
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LabelSelector: labels.Set(
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gp.deployment.Spec.Selector.MatchLabels).AsSelector(),
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})
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if err != nil {
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return nil, err
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}
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readyPods := make([]*v1.Pod, 0, len(podList.Items))
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for _, pod := range podList.Items {
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podReady := true
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for _, cs := range pod.Status.ContainerStatuses {
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podReady = podReady && cs.Ready
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}
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if podReady {
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log.Printf("pod %v is ready", pod.ObjectMeta.Name)
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readyPods = append(readyPods, &pod)
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}
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}
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log.Printf("[%v] found %v ready pods of %v total",
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newLabels, len(readyPods), len(podList.Items))
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// If there are no ready pods, wait and retry.
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if len(readyPods) == 0 {
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err = gp.waitForReadyPod()
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if err != nil {
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return nil, err
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}
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continue
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}
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// Pick a ready pod. For now just choose randomly;
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// ideally we'd care about which node it's running on,
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// and make a good scheduling decision.
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chosenPod := readyPods[rand.Intn(len(readyPods))]
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// Relabel. If the pod already got picked and
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// modified, this should fail; in that case just
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// retry.
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chosenPod.ObjectMeta.Labels = newLabels
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log.Printf("relabeling pod: [%v]", chosenPod.ObjectMeta.Name)
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_, err = gp.kubernetesClient.Core().Pods(gp.namespace).Update(chosenPod)
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if err != nil {
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log.Printf("failed to relabel pod [%v]: %v", chosenPod.ObjectMeta.Name, err)
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continue
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}
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log.Printf("Chosen pod: %v (in %v)", chosenPod.ObjectMeta.Name, time.Now().Sub(startTime))
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return chosenPod, nil
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}
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}
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func labelsForMetadata(metadata *fission.Metadata) map[string]string {
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return map[string]string{
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"functionName": metadata.Name,
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"functionUid": metadata.Uid,
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}
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}
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// specializePod chooses a pod, copies the required user-defined function to that pod
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// (via fetcher), and calls the function-run container to load it, resulting in a
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// specialized pod.
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func (gp *GenericPool) specializePod(metadata *fission.Metadata) (*v1.Pod, error) {
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newLabels := labelsForMetadata(metadata)
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log.Printf("[%v] Choosing pod from pool", metadata)
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pod, err := gp.choosePod(newLabels)
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if err != nil {
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return nil, err
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}
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// for fetcher we don't need to create a service, just talk to the pod directly
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podIP := pod.Status.PodIP
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if len(podIP) == 0 {
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return nil, errors.New("Pod has no IP")
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}
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// tell fetcher to get the function
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fetcherUrl := fmt.Sprintf("http://%v:8000/", podIP)
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functionUrl := fmt.Sprintf("%v/v1/functions/%v?uid=%v&raw=1",
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gp.controllerUrl, metadata.Name, metadata.Uid)
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fetcherRequest := fmt.Sprintf("{\"url\": \"%v\", \"filename\": \"user\"}", functionUrl)
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log.Printf("[%v] calling fetcher to copy function", metadata)
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resp, err := http.Post(fetcherUrl, "application/json", bytes.NewReader([]byte(fetcherRequest)))
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if err != nil {
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return nil, err
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}
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defer resp.Body.Close()
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if resp.StatusCode != 200 {
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return nil, errors.New(fmt.Sprintf("Error from fetcher: %v", resp.Status))
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}
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// get function run container to specialize
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log.Printf("[%v] specializing pod", metadata)
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specializeUrl := fmt.Sprintf("http://%v:8888/specialize", podIP)
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// retry the specialize call a few times in case the env server hasn't come up yet
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maxRetries := 20
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for i := 0; i < maxRetries; i++ {
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resp2, err := http.Post(specializeUrl, "text/plain", bytes.NewReader([]byte{}))
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if err != nil {
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if urlErr, ok := err.(*url.Error); ok {
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if netErr, ok := urlErr.Err.(*net.OpError); ok {
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if netErr.Op == "dial" { // && netErr.Err == syscall.ECONNREFUSED
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log.Printf("Error connecting to pod (%v)", netErr)
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if i < maxRetries-1 {
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time.Sleep(500 * time.Duration(2*i) * time.Millisecond)
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continue
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}
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}
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}
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}
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return nil, err
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}
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resp2.Body.Close()
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}
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return pod, nil
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}
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// A pool is a deployment of generic containers for an env. This
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// creates the pool but doesn't wait for any pods to be ready.
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func (gp *GenericPool) createPool() error {
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poolDeploymentName := fmt.Sprintf("deployment-%v-%v-0",
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gp.env.Metadata.Name, gp.env.Metadata.Uid)
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podLabels := map[string]string{
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"pool": poolDeploymentName,
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}
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sharedMountPath := "/userfunc"
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deployment := &v1beta1.Deployment{
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ObjectMeta: v1.ObjectMeta{
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Name: poolDeploymentName,
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Labels: map[string]string{
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"environmentName": gp.env.Metadata.Name,
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"environmentUid": gp.env.Metadata.Uid,
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},
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},
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Spec: v1beta1.DeploymentSpec{
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Replicas: &gp.replicas,
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Selector: &v1beta1.LabelSelector{
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MatchLabels: podLabels,
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},
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Template: v1.PodTemplateSpec{
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ObjectMeta: v1.ObjectMeta{
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Labels: podLabels,
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},
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Spec: v1.PodSpec{
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Volumes: []v1.Volume{
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v1.Volume{
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Name: "userfunc",
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VolumeSource: v1.VolumeSource{
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EmptyDir: &v1.EmptyDirVolumeSource{},
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},
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},
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},
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Containers: []v1.Container{
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v1.Container{
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Name: gp.env.Metadata.Name,
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Image: gp.env.RunContainerImageUrl,
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ImagePullPolicy: v1.PullIfNotPresent,
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TerminationMessagePath: "/dev/termination-log",
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VolumeMounts: []v1.VolumeMount{
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v1.VolumeMount{
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Name: "userfunc",
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MountPath: sharedMountPath,
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},
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},
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},
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v1.Container{
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Name: "fetcher",
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Image: "fission/fetcher",
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ImagePullPolicy: v1.PullIfNotPresent,
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TerminationMessagePath: "/dev/termination-log",
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VolumeMounts: []v1.VolumeMount{
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v1.VolumeMount{
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Name: "userfunc",
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MountPath: sharedMountPath,
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},
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},
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Command: []string{"/fetcher", sharedMountPath},
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},
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},
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},
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},
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},
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}
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depl, err := gp.kubernetesClient.Extensions().Deployments(gp.namespace).Create(deployment)
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if err != nil {
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return err
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}
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gp.deployment = depl
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return nil
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}
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func (gp *GenericPool) waitForReadyPod() error {
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startTime := time.Now()
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for {
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// TODO: for now we just poll; use a watch instead
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depl, err := gp.kubernetesClient.Extensions().Deployments(gp.namespace).Get(gp.deployment.ObjectMeta.Name)
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if err != nil {
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log.Printf("err: %v", err)
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return err
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}
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gp.deployment = depl
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if gp.deployment.Status.AvailableReplicas > 0 {
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return nil
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}
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if time.Now().Sub(startTime) > gp.podReadyTimeout {
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return errors.New("timeout: waited too long for pod to be ready")
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}
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time.Sleep(1000 * time.Millisecond)
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}
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}
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func (gp *GenericPool) createSvc(name string, labels map[string]string) (*v1.Service, error) {
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service := v1.Service{
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ObjectMeta: v1.ObjectMeta{
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Name: name,
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},
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Spec: v1.ServiceSpec{
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Type: v1.ServiceTypeClusterIP,
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Ports: []v1.ServicePort{
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v1.ServicePort{
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Protocol: v1.ProtocolTCP,
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Port: 80,
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TargetPort: intstr.FromInt(8888),
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},
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},
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Selector: labels,
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},
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}
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svc, err := gp.kubernetesClient.Core().Services(gp.namespace).Create(&service)
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return svc, err
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}
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func (gp *GenericPool) GetFuncSvc(m *fission.Metadata) (*funcSvc, error) {
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pod, err := gp.specializePod(m)
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if err != nil {
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return nil, err
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}
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log.Printf("Specialized pod: %v", pod.ObjectMeta.Name)
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svcName := fmt.Sprintf("svc-%v", m.Name)
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if len(m.Uid) > 0 {
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svcName += ("-" + m.Uid)
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}
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labels := labelsForMetadata(m)
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svc, err := gp.createSvc(svcName, labels)
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if err != nil {
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return nil, err
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}
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if svc.ObjectMeta.Name != svcName {
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return nil, errors.New(fmt.Sprintf("sanity check failed for svc %v", svc.ObjectMeta.Name))
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}
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// the fission router isn't in the same namespace, so return a
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// namespace-qualified hostname
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svcHost := fmt.Sprintf("%v.%v", svcName, gp.namespace)
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fsvc := &funcSvc{
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function: m,
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environment: gp.env,
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serviceName: svcHost,
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ctime: time.Now(),
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atime: time.Now(),
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}
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return fsvc, nil
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}
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