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Merge pull request #19 from mshitrit/run-command-in-cluster
Adding running command in cluster utility to common
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,156 @@ | ||
| package command | ||
|
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||
| import ( | ||
| "bytes" | ||
| "context" | ||
| "fmt" | ||
| "os" | ||
| "strings" | ||
| "time" | ||
|
|
||
| "github.com/go-logr/logr" | ||
|
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| corev1 "k8s.io/api/core/v1" | ||
| metav1 "k8s.io/apimachinery/pkg/apis/meta/v1" | ||
| "k8s.io/apimachinery/pkg/util/wait" | ||
| "k8s.io/client-go/kubernetes" | ||
| "k8s.io/client-go/kubernetes/scheme" | ||
| "k8s.io/client-go/tools/remotecommand" | ||
| "k8s.io/utils/pointer" | ||
| "sigs.k8s.io/controller-runtime/pkg/client/config" | ||
| ) | ||
|
|
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| // RunCommandInCluster runs a command in a pod in the cluster and returns the output | ||
| func RunCommandInCluster(ctx context.Context, c *kubernetes.Clientset, nodeName string, ns string, command string, log logr.Logger) (string, error) { | ||
|
|
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| // create a pod and wait that it's running | ||
| pod := getPod(nodeName) | ||
| pod, err := c.CoreV1().Pods(ns).Create(ctx, pod, metav1.CreateOptions{}) | ||
| if err != nil { | ||
| return "", err | ||
| } | ||
|
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| err = waitForCondition(ctx, c, pod, corev1.PodReady, corev1.ConditionTrue, time.Minute) | ||
| if err != nil { | ||
| log.Error(err, "helper pod isn't ready") | ||
| return "", err | ||
| } | ||
|
|
||
| log.Info("helper pod is running, going to execute command") | ||
| cmd := []string{"sh", "-c", command} | ||
| bytes, err := waitForPodOutput(ctx, c, pod, cmd) | ||
| if err != nil { | ||
| return "", err | ||
| } | ||
| return strings.TrimSpace(string(bytes)), nil | ||
| } | ||
|
|
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| func waitForPodOutput(ctx context.Context, c *kubernetes.Clientset, pod *corev1.Pod, command []string) ([]byte, error) { | ||
| var out []byte | ||
| if err := wait.PollImmediate(1*time.Second, time.Minute, func() (done bool, err error) { | ||
| out, err = execCommandOnPod(ctx, c, pod, command) | ||
| if err != nil { | ||
| return false, err | ||
| } | ||
|
|
||
| return len(out) != 0, nil | ||
| }); err != nil { | ||
| return nil, err | ||
| } | ||
|
|
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| return out, nil | ||
| } | ||
|
|
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| // execCommandOnPod runs command in the pod and returns buffer output | ||
| func execCommandOnPod(ctx context.Context, c *kubernetes.Clientset, pod *corev1.Pod, command []string) ([]byte, error) { | ||
| var outputBuf bytes.Buffer | ||
| var errorBuf bytes.Buffer | ||
|
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||
| req := c.CoreV1().RESTClient(). | ||
| Post(). | ||
| Namespace(pod.Namespace). | ||
| Resource("pods"). | ||
| Name(pod.Name). | ||
| SubResource("exec"). | ||
| VersionedParams(&corev1.PodExecOptions{ | ||
| Container: pod.Spec.Containers[0].Name, | ||
| Command: command, | ||
| Stdin: true, | ||
| Stdout: true, | ||
| Stderr: true, | ||
| TTY: true, | ||
| }, scheme.ParameterCodec) | ||
|
|
||
| cfg, err := config.GetConfig() | ||
| if err != nil { | ||
| return nil, err | ||
| } | ||
|
|
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| exec, err := remotecommand.NewSPDYExecutor(cfg, "POST", req.URL()) | ||
| if err != nil { | ||
| return nil, err | ||
| } | ||
|
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| err = exec.StreamWithContext(ctx, remotecommand.StreamOptions{ | ||
| Stdin: os.Stdin, | ||
| Stdout: &outputBuf, | ||
| Stderr: &errorBuf, | ||
| Tty: true, | ||
| }) | ||
| if err != nil { | ||
| return nil, fmt.Errorf("failed to run command %v: error: %v, outputStream %s; errorStream %s", command, err, outputBuf.String(), errorBuf.String()) | ||
| } | ||
|
|
||
| if errorBuf.Len() != 0 { | ||
| return nil, fmt.Errorf("failed to run command %v: output %s; error %s", command, outputBuf.String(), errorBuf.String()) | ||
| } | ||
|
|
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| return outputBuf.Bytes(), nil | ||
| } | ||
|
|
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| // waitForCondition waits until the pod will have specified condition type with the expected status | ||
| func waitForCondition(ctx context.Context, c *kubernetes.Clientset, pod *corev1.Pod, conditionType corev1.PodConditionType, conditionStatus corev1.ConditionStatus, timeout time.Duration) error { | ||
| return wait.PollImmediate(time.Second, timeout, func() (bool, error) { | ||
| updatedPod, err := c.CoreV1().Pods(pod.Namespace).Get(ctx, pod.Name, metav1.GetOptions{}) | ||
| if err != nil { | ||
| return false, err | ||
| } | ||
| for _, c := range updatedPod.Status.Conditions { | ||
| if c.Type == conditionType && c.Status == conditionStatus { | ||
| return true, nil | ||
| } | ||
| } | ||
| return false, nil | ||
| }) | ||
| } | ||
|
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||
| func getPod(nodeName string) *corev1.Pod { | ||
| return &corev1.Pod{ | ||
| ObjectMeta: metav1.ObjectMeta{ | ||
| GenerateName: "executer-pod-test-", | ||
| Labels: map[string]string{ | ||
| "test": "", | ||
| }, | ||
| }, | ||
| Spec: corev1.PodSpec{ | ||
| NodeName: nodeName, | ||
| HostNetwork: true, | ||
| HostPID: true, | ||
| SecurityContext: &corev1.PodSecurityContext{ | ||
| RunAsUser: pointer.Int64(0), | ||
| RunAsGroup: pointer.Int64(0), | ||
| }, | ||
| RestartPolicy: corev1.RestartPolicyNever, | ||
| Containers: []corev1.Container{ | ||
| { | ||
| Name: "test", | ||
| Image: "registry.access.redhat.com/ubi8/ubi-minimal", | ||
| SecurityContext: &corev1.SecurityContext{ | ||
| Privileged: pointer.Bool(true), | ||
| }, | ||
| Command: []string{"sleep", "2m"}, | ||
| }, | ||
| }, | ||
| }, | ||
| } | ||
| } |