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Add builtin func to exec into K8s pods (#272)
* Add builtin func to exec into K8s pods * format code --------- Co-authored-by: Atanas Todorov <[email protected]>
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,14 @@ | ||
| work_dir = args.workdir if hasattr(args, "workdir") else fail("Error: workdir argument is required but not provided.") | ||
| conf = crashd_config(workdir=work_dir) | ||
| kube_config_path = args.kubeconfig | ||
| set_defaults(kube_config(path=kube_config_path)) | ||
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| # Exec into pod and run a long-running command. The command timeout period is controlled via timeout_in_seconds | ||
| #Output is appended in file under work_dir/<pod name>.out | ||
| kube_exec(namespace=args.namespace,pod="nginx", timeout_in_seconds=3, cmd=["sh", "-c" ,"while true; do echo 'Running'; sleep 1; done"]) | ||
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| # Exec into pod and run short-lived command. The output will be appended in work_dir/<pod name>.out | ||
| kube_exec(pod="nginx", cmd=["ls"]) | ||
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| # Exec into pod and run short-lived command. The output will be stored into file: work_dir/nginx_version.txt | ||
| kube_exec(pod="nginx", output_file="nginx_version.txt",container="nginx", cmd=["nginx", "-v"]) |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,109 @@ | ||
| // Copyright (c) 2019 VMware, Inc. All Rights Reserved. | ||
| // SPDX-License-Identifier: Apache-2.0 | ||
|
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| package k8s | ||
|
|
||
| import ( | ||
| "context" | ||
| "fmt" | ||
| corev1 "k8s.io/api/core/v1" | ||
| "k8s.io/client-go/kubernetes/scheme" | ||
| "k8s.io/client-go/rest" | ||
| "k8s.io/client-go/tools/clientcmd" | ||
| "k8s.io/client-go/tools/remotecommand" | ||
| "os" | ||
| "time" | ||
| ) | ||
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| // Executor is a struct that facilitates the execution of commands in Kubernetes pods. | ||
| // It uses the SPDYExecutor to stream command | ||
| type Executor struct { | ||
| Executor remotecommand.Executor | ||
| } | ||
|
|
||
| type ExecOptions struct { | ||
| Namespace string | ||
| Command []string | ||
| Podname string | ||
| ContainerName string | ||
| Config *Config | ||
| Timeout time.Duration | ||
| } | ||
|
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| func NewExecutor(kubeconfig string, clusterCtxName string, opts ExecOptions) (*Executor, error) { | ||
| restCfg, err := restConfig(kubeconfig, clusterCtxName) | ||
| if err != nil { | ||
| return nil, err | ||
| } | ||
| setCoreDefaultConfig(restCfg) | ||
| restc, err := rest.RESTClientFor(restCfg) | ||
| if err != nil { | ||
| return nil, err | ||
| } | ||
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| request := restc.Post(). | ||
| Namespace(opts.Namespace). | ||
| Resource("pods"). | ||
| Name(opts.Podname). | ||
| SubResource("exec"). | ||
| VersionedParams(&corev1.PodExecOptions{ | ||
| Container: opts.ContainerName, | ||
| Command: opts.Command, | ||
| Stdout: true, | ||
| Stderr: true, | ||
| TTY: false, | ||
| }, scheme.ParameterCodec) | ||
| executor, err := remotecommand.NewSPDYExecutor(restCfg, "POST", request.URL()) | ||
| if err != nil { | ||
| return nil, err | ||
|
|
||
| } | ||
| return &Executor{Executor: executor}, nil | ||
| } | ||
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| // makeRESTConfig creates a new *rest.Config with a k8s context name if one is provided. | ||
| func restConfig(fileName, contextName string) (*rest.Config, error) { | ||
| if fileName == "" { | ||
| return nil, fmt.Errorf("kubeconfig file path required") | ||
| } | ||
|
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| if contextName != "" { | ||
| // create the config object from k8s config path and context | ||
| return clientcmd.NewNonInteractiveDeferredLoadingClientConfig( | ||
| &clientcmd.ClientConfigLoadingRules{ExplicitPath: fileName}, | ||
| &clientcmd.ConfigOverrides{ | ||
| CurrentContext: contextName, | ||
| }).ClientConfig() | ||
| } | ||
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| return clientcmd.NewNonInteractiveDeferredLoadingClientConfig( | ||
| &clientcmd.ClientConfigLoadingRules{ExplicitPath: fileName}, | ||
| &clientcmd.ConfigOverrides{}, | ||
| ).ClientConfig() | ||
| } | ||
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| // ExecCommand executes a command inside a specified Kubernetes pod using the SPDYExecutor. | ||
| func (k8sc *Executor) ExecCommand(ctx context.Context, outputFilePath string, execOptions ExecOptions) error { | ||
| ctx, cancel := context.WithTimeout(ctx, execOptions.Timeout) | ||
| defer cancel() | ||
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| file, err := os.OpenFile(outputFilePath, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644) | ||
| if err != nil { | ||
| return fmt.Errorf("error creating output file: %v", err) | ||
| } | ||
| defer file.Close() | ||
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| // Execute the command and stream the stdout and stderr to the file. Some commands are using stderr. | ||
| err = k8sc.Executor.StreamWithContext(ctx, remotecommand.StreamOptions{ | ||
| Stdout: file, | ||
| Stderr: file, | ||
| }) | ||
| if err != nil { | ||
| if err == context.DeadlineExceeded { | ||
| return fmt.Errorf("command execution timed out. command:%s", execOptions.Command) | ||
| } | ||
| return err | ||
| } | ||
|
|
||
| return nil | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,96 @@ | ||
| // Copyright (c) 2020 VMware, Inc. All Rights Reserved. | ||
| // SPDX-License-Identifier: Apache-2.0 | ||
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| package starlark | ||
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| import ( | ||
| "context" | ||
| "fmt" | ||
| "github.com/pkg/errors" | ||
| "github.com/vmware-tanzu/crash-diagnostics/k8s" | ||
| "go.starlark.net/starlark" | ||
| "go.starlark.net/starlarkstruct" | ||
| "path/filepath" | ||
| "time" | ||
| ) | ||
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| // KubeExecFn is a starlark built-in for executing command in target K8s pods | ||
| func KubeExecFn(thread *starlark.Thread, _ *starlark.Builtin, args starlark.Tuple, kwargs []starlark.Tuple) (starlark.Value, error) { | ||
| var namespace, pod, container, workdir, outputfile string | ||
| var timeout int | ||
| var command *starlark.List | ||
| var kubeConfig *starlarkstruct.Struct | ||
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| if err := starlark.UnpackArgs( | ||
| identifiers.kubeExec, args, kwargs, | ||
| "namespace?", &namespace, | ||
| "pod", &pod, | ||
| "container?", &container, | ||
| "cmd", &command, | ||
| "workdir?", &workdir, | ||
| "output_file?", &outputfile, | ||
| "kube_config?", &kubeConfig, | ||
| "timeout_in_seconds?", &timeout, | ||
| ); err != nil { | ||
| return starlark.None, errors.Wrap(err, "failed to read args") | ||
| } | ||
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| if namespace == "" { | ||
| namespace = "default" | ||
| } | ||
| if timeout == 0 { | ||
| //Default timeout if not specified is 2 Minutes | ||
| timeout = 120 | ||
| } | ||
|
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| if len(workdir) == 0 { | ||
| //Defaults to crashd_config.workdir or /tmp/crashd | ||
| if dir, err := getWorkdirFromThread(thread); err == nil { | ||
| workdir = dir | ||
| } | ||
| } | ||
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| ctx, ok := thread.Local(identifiers.scriptCtx).(context.Context) | ||
| if !ok || ctx == nil { | ||
| return starlark.None, fmt.Errorf("script context not found") | ||
| } | ||
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| if kubeConfig == nil { | ||
| kubeConfig = thread.Local(identifiers.kubeCfg).(*starlarkstruct.Struct) | ||
| } | ||
| path, err := getKubeConfigPathFromStruct(kubeConfig) | ||
| if err != nil { | ||
| return starlark.None, errors.Wrap(err, "failed to get kubeconfig") | ||
| } | ||
| clusterCtxName := getKubeConfigContextNameFromStruct(kubeConfig) | ||
|
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| execOpts := k8s.ExecOptions{ | ||
| Namespace: namespace, | ||
| Podname: pod, | ||
| ContainerName: container, | ||
| Command: toSlice(command), | ||
| Timeout: time.Duration(timeout) * time.Second, | ||
| } | ||
| executor, err := k8s.NewExecutor(path, clusterCtxName, execOpts) | ||
| if err != nil { | ||
| return starlark.None, errors.Wrap(err, "could not initialize search client") | ||
| } | ||
|
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| outputFilePath := filepath.Join(trimQuotes(workdir), outputfile) | ||
| if outputfile == "" { | ||
| outputFilePath = filepath.Join(trimQuotes(workdir), pod+".out") | ||
| } | ||
| err = executor.ExecCommand(ctx, outputFilePath, execOpts) | ||
|
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| return starlarkstruct.FromStringDict( | ||
| starlark.String(identifiers.kubeCapture), | ||
| starlark.StringDict{ | ||
| "file": starlark.String(outputFilePath), | ||
| "error": func() starlark.String { | ||
| if err != nil { | ||
| return starlark.String(err.Error()) | ||
| } | ||
| return "" | ||
| }(), | ||
| }), nil | ||
| } |
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