feat: pods_exec minimal implementation

Author: manusa

README.md

@@ -16,13 +16,14 @@ A powerful and flexible Kubernetes [Model Context Protocol (MCP)](https://blog.m
 - **✅ Configuration**:
   - Automatically detect changes in the Kubernetes configuration and update the MCP server.
   - **View** and manage the current [Kubernetes `.kube/config`](https://blog.marcnuri.com/where-is-my-default-kubeconfig-file) or in-cluster configuration.
-- **✅ Generic Kubernetes Resources**: Perform operations on any Kubernetes resource.
+- **✅ Generic Kubernetes Resources**: Perform operations on **any** Kubernetes or OpenShift resource.
   - Any CRUD operation (Create or Update, Get, List, Delete).
 - **✅ Pods**: Perform Pod-specific operations.
   - **List** pods in all namespaces or in a specific namespace.
   - **Get** a pod by name from the specified namespace.
   - **Delete** a pod by name from the specified namespace.
   - **Show logs** for a pod by name from the specified namespace.
+  - **Exec** into a pod and run a command.
   - **Run** a container image in a pod and optionally expose it.
 - **✅ Namespaces**: List Kubernetes Namespaces.
 - **✅ Events**: View Kubernetes events in all namespaces or in a specific namespace.

go.mod

@@ -35,13 +35,16 @@ require (
 	github.com/google/go-cmp v0.6.0 // indirect
 	github.com/google/gofuzz v1.2.0 // indirect
 	github.com/google/uuid v1.6.0 // indirect
+	github.com/gorilla/websocket v1.5.0 // indirect
 	github.com/inconshreveable/mousetrap v1.1.0 // indirect
 	github.com/josharian/intern v1.0.0 // indirect
 	github.com/json-iterator/go v1.1.12 // indirect
 	github.com/mailru/easyjson v0.7.7 // indirect
+	github.com/moby/spdystream v0.5.0 // indirect
 	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
 	github.com/modern-go/reflect2 v1.0.2 // indirect
 	github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 // indirect
+	github.com/mxk/go-flowrate v0.0.0-20140419014527-cca7078d478f // indirect
 	github.com/pelletier/go-toml/v2 v2.2.3 // indirect
 	github.com/pkg/errors v0.9.1 // indirect
 	github.com/sagikazarmark/locafero v0.7.0 // indirect

go.sum

@@ -1,3 +1,5 @@
+github.com/armon/go-socks5 v0.0.0-20160902184237-e75332964ef5 h1:0CwZNZbxp69SHPdPJAN/hZIm0C4OItdklCFmMRWYpio=
+github.com/armon/go-socks5 v0.0.0-20160902184237-e75332964ef5/go.mod h1:wHh0iHkYZB8zMSxRWpUBQtwG5a7fFgvEO+odwuTv2gs=
 github.com/beorn7/perks v1.0.1 h1:VlbKKnNfV8bJzeqoa4cOKqO6bYr3WgKZxO8Z16+hsOM=
 github.com/beorn7/perks v1.0.1/go.mod h1:G2ZrVWU2WbWT9wwq4/hrbKbnv/1ERSJQ0ibhJ6rlkpw=
 github.com/cespare/xxhash/v2 v2.3.0 h1:UL815xU9SqsFlibzuggzjXhog7bL6oX9BbNZnL2UFvs=
@@ -50,6 +52,8 @@ github.com/google/pprof v0.0.0-20241210010833-40e02aabc2ad h1:a6HEuzUHeKH6hwfN/Z
 github.com/google/pprof v0.0.0-20241210010833-40e02aabc2ad/go.mod h1:vavhavw2zAxS5dIdcRluK6cSGGPlZynqzFM8NdvU144=
 github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
 github.com/google/uuid v1.6.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
+github.com/gorilla/websocket v1.5.0 h1:PPwGk2jz7EePpoHN/+ClbZu8SPxiqlu12wZP/3sWmnc=
+github.com/gorilla/websocket v1.5.0/go.mod h1:YR8l580nyteQvAITg2hZ9XVh4b55+EU/adAjf1fMHhE=
 github.com/inconshreveable/mousetrap v1.1.0 h1:wN+x4NVGpMsO7ErUn/mUI3vEoE6Jt13X2s0bqwp9tc8=
 github.com/inconshreveable/mousetrap v1.1.0/go.mod h1:vpF70FUmC8bwa3OWnCshd2FqLfsEA9PFc4w1p2J65bw=
 github.com/josharian/intern v1.0.0 h1:vlS4z54oSdjm0bgjRigI+G1HpF+tI+9rE5LLzOg8HmY=
@@ -69,13 +73,17 @@ github.com/mailru/easyjson v0.7.7 h1:UGYAvKxe3sBsEDzO8ZeWOSlIQfWFlxbzLZe7hwFURr0
 github.com/mailru/easyjson v0.7.7/go.mod h1:xzfreul335JAWq5oZzymOObrkdz5UnU4kGfJJLY9Nlc=
 github.com/mark3labs/mcp-go v0.16.0 h1:hNOr0EqhSUra5jm1Wv6+BOynzIa+bMtfP3zgde70MvY=
 github.com/mark3labs/mcp-go v0.16.0/go.mod h1:KmJndYv7GIgcPVwEKJjNcbhVQ+hJGJhrCCB/9xITzpE=
+github.com/moby/spdystream v0.5.0 h1:7r0J1Si3QO/kjRitvSLVVFUjxMEb/YLj6S9FF62JBCU=
+github.com/moby/spdystream v0.5.0/go.mod h1:xBAYlnt/ay+11ShkdFKNAG7LsyK/tmNBVvVOwrfMgdI=
 github.com/modern-go/concurrent v0.0.0-20180228061459-e0a39a4cb421/go.mod h1:6dJC0mAP4ikYIbvyc7fijjWJddQyLn8Ig3JB5CqoB9Q=
 github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd h1:TRLaZ9cD/w8PVh93nsPXa1VrQ6jlwL5oN8l14QlcNfg=
 github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd/go.mod h1:6dJC0mAP4ikYIbvyc7fijjWJddQyLn8Ig3JB5CqoB9Q=
 github.com/modern-go/reflect2 v1.0.2 h1:xBagoLtFs94CBntxluKeaWgTMpvLxC4ur3nMaC9Gz0M=
 github.com/modern-go/reflect2 v1.0.2/go.mod h1:yWuevngMOJpCy52FWWMvUC8ws7m/LJsjYzDa0/r8luk=
 github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 h1:C3w9PqII01/Oq1c1nUAm88MOHcQC9l5mIlSMApZMrHA=
 github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822/go.mod h1:+n7T8mK8HuQTcFwEeznm/DIxMOiR9yIdICNftLE1DvQ=
+github.com/mxk/go-flowrate v0.0.0-20140419014527-cca7078d478f h1:y5//uYreIhSUg3J1GEMiLbxo1LJaP8RfCpH6pymGZus=
+github.com/mxk/go-flowrate v0.0.0-20140419014527-cca7078d478f/go.mod h1:ZdcZmHo+o7JKHSa8/e818NopupXU1YMK5fe1lsApnBw=
 github.com/onsi/ginkgo/v2 v2.22.2 h1:/3X8Panh8/WwhU/3Ssa6rCKqPLuAkVY2I0RoyDLySlU=
 github.com/onsi/ginkgo/v2 v2.22.2/go.mod h1:oeMosUL+8LtarXBHu/c0bx2D/K9zyQ6uX3cTyztHwsk=
 github.com/onsi/gomega v1.36.2 h1:koNYke6TVk6ZmnyHrCXba/T/MoLBXFjeC1PtvYgw0A8=

pkg/kubernetes/kubernetes.go

@@ -2,7 +2,9 @@ package kubernetes
 
 import (
 	"github.com/fsnotify/fsnotify"
+	v1 "k8s.io/api/core/v1"
 	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
+	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/client-go/discovery"
 	"k8s.io/client-go/discovery/cached/memory"
 	"k8s.io/client-go/dynamic"
@@ -24,6 +26,8 @@ type Kubernetes struct {
 	cfg                         *rest.Config
 	kubeConfigFiles             []string
 	CloseWatchKubeConfig        CloseWatchKubeConfig
+	scheme                      *runtime.Scheme
+	parameterCodec              *runtime.ParameterCodec
 	clientSet                   *kubernetes.Clientset
 	discoveryClient             *discovery.DiscoveryClient
 	deferredDiscoveryRESTMapper *restmapper.DeferredDiscoveryRESTMapper
@@ -47,9 +51,16 @@ func NewKubernetes() (*Kubernetes, error) {
 	if err != nil {
 		return nil, err
 	}
+	scheme := runtime.NewScheme()
+	if err = v1.AddToScheme(scheme); err != nil {
+		return nil, err
+	}
+	parameterCodec := runtime.NewParameterCodec(scheme)
 	return &Kubernetes{
 		cfg:                         cfg,
 		kubeConfigFiles:             resolveConfig().ConfigAccess().GetLoadingPrecedence(),
+		scheme:                      scheme,
+		parameterCodec:              &parameterCodec,
 		clientSet:                   clientSet,
 		discoveryClient:             discoveryClient,
 		deferredDiscoveryRESTMapper: restmapper.NewDeferredDiscoveryRESTMapper(memory.NewMemCacheClient(discoveryClient)),

pkg/kubernetes/pods.go

@@ -1,16 +1,20 @@
 package kubernetes
 
 import (
+	"bytes"
 	"context"
+	"fmt"
 	"github.com/manusa/kubernetes-mcp-server/pkg/version"
 	v1 "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
 	labelutil "k8s.io/apimachinery/pkg/labels"
 	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/apimachinery/pkg/runtime/schema"
+	"k8s.io/apimachinery/pkg/util/httpstream"
 	"k8s.io/apimachinery/pkg/util/intstr"
 	"k8s.io/apimachinery/pkg/util/rand"
+	"k8s.io/client-go/tools/remotecommand"
 )
 
 func (k *Kubernetes) PodsListInAllNamespaces(ctx context.Context) (string, error) {
@@ -168,3 +172,63 @@ func (k *Kubernetes) PodsRun(ctx context.Context, namespace, name, image string,
 	}
 	return k.resourcesCreateOrUpdate(ctx, toCreate)
 }
+
+func (k *Kubernetes) PodsExec(ctx context.Context, namespace, name, container string, command []string) (string, error) {
+	namespace = namespaceOrDefault(namespace)
+	pod, err := k.clientSet.CoreV1().Pods(namespace).Get(ctx, name, metav1.GetOptions{})
+	if err != nil {
+		return "", err
+	}
+	// https://github.com/kubernetes/kubectl/blob/5366de04e168bcbc11f5e340d131a9ca8b7d0df4/pkg/cmd/exec/exec.go#L350-L352
+	if pod.Status.Phase == v1.PodSucceeded || pod.Status.Phase == v1.PodFailed {
+		return "", fmt.Errorf("cannot exec into a container in a completed pod; current phase is %s", pod.Status.Phase)
+	}
+	podExecOptions := &v1.PodExecOptions{
+		Command: command,
+		Stdout:  true,
+		Stderr:  true,
+	}
+	executor, err := k.createExecutor(namespace, name, podExecOptions)
+	if err != nil {
+		return "", err
+	}
+	if container == "" {
+		container = pod.Spec.Containers[0].Name
+	}
+	stdout := bytes.NewBuffer(make([]byte, 0))
+	stderr := bytes.NewBuffer(make([]byte, 0))
+	if err = executor.StreamWithContext(ctx, remotecommand.StreamOptions{
+		Stdout: stdout, Stderr: stderr, Tty: false,
+	}); err != nil {
+		return "", err
+	}
+	if stdout.Len() > 0 {
+		return stdout.String(), nil
+	}
+	if stderr.Len() > 0 {
+		return stderr.String(), nil
+	}
+	return "", nil
+}
+
+func (k *Kubernetes) createExecutor(namespace, name string, podExecOptions *v1.PodExecOptions) (remotecommand.Executor, error) {
+	// Compute URL
+	// https://github.com/kubernetes/kubectl/blob/5366de04e168bcbc11f5e340d131a9ca8b7d0df4/pkg/cmd/exec/exec.go#L382-L397
+	req := k.clientSet.CoreV1().RESTClient().Post().
+		Resource("pods").
+		Namespace(namespace).
+		Name(name).
+		SubResource("exec")
+	req.VersionedParams(podExecOptions, *k.parameterCodec)
+	spdyExec, err := remotecommand.NewSPDYExecutor(k.cfg, "POST", req.URL())
+	if err != nil {
+		return nil, err
+	}
+	webSocketExec, err := remotecommand.NewWebSocketExecutor(k.cfg, "GET", req.URL().String())
+	if err != nil {
+		return nil, err
+	}
+	return remotecommand.NewFallbackExecutor(webSocketExec, spdyExec, func(err error) bool {
+		return httpstream.IsUpgradeFailure(err) || httpstream.IsHTTPSProxyError(err)
+	})
+}

pkg/mcp/pods.go

@@ -27,6 +27,24 @@ func (s *Server) initPods() []server.ServerTool {
 			mcp.WithString("namespace", mcp.Description("Namespace to delete the Pod from")),
 			mcp.WithString("name", mcp.Description("Name of the Pod to delete"), mcp.Required()),
 		), s.podsDelete},
+		{mcp.NewTool("pods_exec",
+			mcp.WithDescription("Execute a command in a Kubernetes Pod in the current or provided namespace with the provided name and command"),
+			mcp.WithString("namespace", mcp.Description("Namespace to get the Pod logs from")),
+			mcp.WithString("name", mcp.Description("Name of the Pod to get the logs from"), mcp.Required()),
+			mcp.WithArray("command", mcp.Description("Command to execute in the Pod container. "+
+				"The first item is the command to be run, and the rest are the arguments to that command. "+
+				`Example: ["ls", "-l", "/tmp"]`),
+				// TODO: manual fix to ensure that the items property gets initialized (Gemini)
+				// https://www.googlecloudcommunity.com/gc/AI-ML/Gemini-API-400-Bad-Request-Array-fields-breaks-function-calling/m-p/769835?nobounce
+				func(schema map[string]interface{}) {
+					schema["type"] = "array"
+					schema["items"] = map[string]interface{}{
+						"type": "string",
+					}
+				},
+				mcp.Required(),
+			),
+		), s.podsExec},
 		{mcp.NewTool("pods_log",
 			mcp.WithDescription("Get the logs of a Kubernetes Pod in the current or provided namespace with the provided name"),
 			mcp.WithString("namespace", mcp.Description("Namespace to get the Pod logs from")),
@@ -94,6 +112,35 @@ func (s *Server) podsDelete(ctx context.Context, ctr mcp.CallToolRequest) (*mcp.
 	return NewTextResult(ret, err), nil
 }
 
+func (s *Server) podsExec(ctx context.Context, ctr mcp.CallToolRequest) (*mcp.CallToolResult, error) {
+	ns := ctr.Params.Arguments["namespace"]
+	if ns == nil {
+		ns = ""
+	}
+	name := ctr.Params.Arguments["name"]
+	if name == nil {
+		return NewTextResult("", errors.New("failed to exec in pod, missing argument name")), nil
+	}
+	commandArg := ctr.Params.Arguments["command"]
+	command := make([]string, 0)
+	if _, ok := commandArg.([]interface{}); ok {
+		for _, cmd := range commandArg.([]interface{}) {
+			if _, ok := cmd.(string); ok {
+				command = append(command, cmd.(string))
+			}
+		}
+	} else {
+		return NewTextResult("", errors.New("failed to exec in pod, invalid command argument")), nil
+	}
+	ret, err := s.k.PodsExec(ctx, ns.(string), name.(string), "", command)
+	if err != nil {
+		return NewTextResult("", fmt.Errorf("failed to exec in pod %s in namespace %s: %v", name, ns, err)), nil
+	} else if ret == "" {
+		ret = fmt.Sprintf("The executed command in pod %s in namespace %s has not produced any output", name, ns)
+	}
+	return NewTextResult(ret, err), nil
+}
+
 func (s *Server) podsLog(ctx context.Context, ctr mcp.CallToolRequest) (*mcp.CallToolResult, error) {
 	ns := ctr.Params.Arguments["namespace"]
 	if ns == nil {