Add flux logs command

Signed-off-by: Somtochi Onyekwere <somtochionyekwere@gmail.com>

cmd/flux/logs.go

@@ -0,0 +1,262 @@
+/*
+Copyright 2021 The Flux authors
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package main
+
+import (
+	"bufio"
+	"context"
+	"encoding/json"
+	"fmt"
+	"github.com/fluxcd/flux2/internal/flags"
+	"github.com/fluxcd/flux2/internal/utils"
+	"github.com/spf13/cobra"
+	"html/template"
+	"io"
+	corev1 "k8s.io/api/core/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/client-go/kubernetes"
+	"k8s.io/client-go/rest"
+	"os"
+	"strings"
+	"sync"
+)
+
+var logsCmd = &cobra.Command{
+	Use:   "logs",
+	Short: "Display formatted logs for toolkit components",
+	Long:  "The logs command displays formatted logs from various toolkit components.",
+	Example: `# Get logs from toolkit components
+	 flux logs
+
+	# Stream logs from toolkit components
+	flux logs --follow
+ 
+	# Get logs from toolkit components in a particular namespace
+	flux logs --flux-namespace my-namespace
+
+	# Get logs for a particular log level
+	flux logs --level=info
+
+	# Filter logs by kind, name, or namespace
+	flux logs --kind=kustomization --name podinfo --namespace default
+    `,
+	RunE: logsCmdRun,
+}
+
+type logsFlags struct {
+	logLevel      flags.LogLevel
+	follow        bool
+	tail          int64
+	kind          string
+	name          string
+	fluxNamespace string
+	allNamespaces bool
+}
+
+var logsArgs = &logsFlags{
+	tail: -1,
+}
+
+func init() {
+	logsCmd.Flags().Var(&logsArgs.logLevel, "level", logsArgs.logLevel.Description())
+	logsCmd.Flags().StringVarP(&logsArgs.kind, "kind", "", logsArgs.kind, "displays errors of a particular toolkit kind e.g GitRepository")
+	logsCmd.Flags().StringVarP(&logsArgs.name, "name", "", logsArgs.name, "specifies the name of the object logs to be displayed")
+	logsCmd.Flags().BoolVarP(&logsArgs.follow, "follow", "f", logsArgs.follow, "Specifies if the logs should be streamed")
+	logsCmd.Flags().Int64VarP(&logsArgs.tail, "tail", "", logsArgs.tail, "lines of recent log file to display")
+	logsCmd.Flags().StringVarP(&logsArgs.fluxNamespace, "flux-namespace", "", rootArgs.defaults.Namespace, "the namespace where the Flux components are running.")
+	logsCmd.Flags().BoolVarP(&logsArgs.allNamespaces, "all-namespaces", "A", false, "displays logs for objects across all namespaces")
+	rootCmd.AddCommand(logsCmd)
+}
+
+func logsCmdRun(cmd *cobra.Command, args []string) error {
+	fluxSelector := fmt.Sprintf("app.kubernetes.io/instance=%s", logsArgs.fluxNamespace)
+
+	ctx, cancel := context.WithTimeout(context.Background(), rootArgs.timeout)
+	defer cancel()
+
+	var pods []corev1.Pod
+	cfg, err := utils.KubeConfig(rootArgs.kubeconfig, rootArgs.kubecontext)
+	if err != nil {
+		return err
+	}
+
+	clientset, err := kubernetes.NewForConfig(cfg)
+	if err != nil {
+		return err
+	}
+
+	if len(args) > 0 {
+		return fmt.Errorf("no argument required")
+	}
+
+	pods, err = getPods(ctx, clientset, fluxSelector)
+	if err != nil {
+		return err
+	}
+
+	logOpts := &corev1.PodLogOptions{
+		Follow: logsArgs.follow,
+	}
+
+	if logsArgs.tail > -1 {
+		logOpts.TailLines = &logsArgs.tail
+	}
+
+	var requests []rest.ResponseWrapper
+	for _, pod := range pods {
+		req := clientset.CoreV1().Pods(logsArgs.fluxNamespace).GetLogs(pod.Name, logOpts)
+		requests = append(requests, req)
+	}
+
+	if logsArgs.follow && len(requests) > 1 {
+		return parallelPodLogs(ctx, requests)
+	}
+
+	return podLogs(ctx, requests)
+}
+
+func getPods(ctx context.Context, c *kubernetes.Clientset, label string) ([]corev1.Pod, error) {
+	var ret []corev1.Pod
+
+	opts := metav1.ListOptions{
+		LabelSelector: label,
+	}
+	deployList, err := c.AppsV1().Deployments(logsArgs.fluxNamespace).List(ctx, opts)
+	if err != nil {
+		return ret, err
+	}
+
+	for _, deploy := range deployList.Items {
+		label := deploy.Spec.Template.Labels
+		opts := metav1.ListOptions{
+			LabelSelector: createLabelStringFromMap(label),
+		}
+		podList, err := c.CoreV1().Pods(logsArgs.fluxNamespace).List(ctx, opts)
+		if err != nil {
+			return ret, err
+		}
+		ret = append(ret, podList.Items...)
+	}
+
+	return ret, nil
+}
+
+func parallelPodLogs(ctx context.Context, requests []rest.ResponseWrapper) error {
+	reader, writer := io.Pipe()
+	wg := &sync.WaitGroup{}
+	wg.Add(len(requests))
+
+	var mutex = &sync.Mutex{}
+
+	for _, request := range requests {
+		go func(req rest.ResponseWrapper) {
+			defer wg.Done()
+			if err := logRequest(mutex, ctx, req, os.Stdout); err != nil {
+				writer.CloseWithError(err)
+				return
+			}
+		}(request)
+	}
+
+	go func() {
+		wg.Wait()
+		writer.Close()
+	}()
+
+	_, err := io.Copy(os.Stdout, reader)
+	return err
+}
+
+func podLogs(ctx context.Context, requests []rest.ResponseWrapper) error {
+	mutex := &sync.Mutex{}
+	for _, req := range requests {
+		if err := logRequest(mutex, ctx, req, os.Stdout); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func createLabelStringFromMap(m map[string]string) string {
+	var strArr []string
+	for key, val := range m {
+		pair := fmt.Sprintf("%v=%v", key, val)
+		strArr = append(strArr, pair)
+	}
+
+	return strings.Join(strArr, ",")
+}
+
+func logRequest(mu *sync.Mutex, ctx context.Context, request rest.ResponseWrapper, w io.Writer) error {
+	stream, err := request.Stream(ctx)
+	if err != nil {
+		return err
+	}
+	defer stream.Close()
+
+	scanner := bufio.NewScanner(stream)
+
+	const logTmpl = "{{.Timestamp}} {{.Level}} {{.Kind}}{{if .Name}}/{{.Name}}.{{.Namespace}}{{end}} - {{.Message}} {{.Error}}\n"
+	t, err := template.New("log").Parse(logTmpl)
+	if err != nil {
+		return fmt.Errorf("unable to create template, err: %s", err)
+	}
+
+	for scanner.Scan() {
+		line := scanner.Text()
+		if !strings.HasPrefix(line, "{") {
+			continue
+		}
+		var l ControllerLogEntry
+		if err := json.Unmarshal([]byte(line), &l); err != nil {
+			logger.Failuref("parse error: %s", err)
+			break
+		}
+
+		mu.Lock()
+		filterPrintLog(t, &l)
+		mu.Unlock()
+	}
+
+	return nil
+}
+
+func filterPrintLog(t *template.Template, l *ControllerLogEntry) {
+	if logsArgs.logLevel != "" && logsArgs.logLevel != l.Level ||
+		logsArgs.kind != "" && strings.ToLower(logsArgs.kind) != strings.ToLower(l.Kind) ||
+		logsArgs.name != "" && strings.ToLower(logsArgs.name) != strings.ToLower(l.Name) ||
+		!logsArgs.allNamespaces && strings.ToLower(rootArgs.namespace) != strings.ToLower(l.Namespace) {
+		return
+	}
+
+	err := t.Execute(os.Stdout, l)
+	if err != nil {
+		logger.Failuref("log template error: %s", err)
+	}
+}
+
+type ControllerLogEntry struct {
+	Timestamp string         `json:"ts"`
+	Level     flags.LogLevel `json:"level"`
+	Message   string         `json:"msg"`
+	Error     string         `json:"error,omitempty"`
+	Logger    string         `json:"logger"`
+	Kind      string         `json:"reconciler kind,omitempty"`
+	Name      string         `json:"name,omitempty"`
+	Namespace string         `json:"namespace,omitempty"`
+}

docs/cmd/flux.md

@@ -85,6 +85,7 @@ Command line utility for assembling Kubernetes CD pipelines the GitOps way.
 * [flux export](flux_export.md)	 - Export resources in YAML format
 * [flux get](flux_get.md)	 - Get sources and resources
 * [flux install](flux_install.md)	 - Install or upgrade Flux
+* [flux logs](flux_logs.md)	 - Display formatted logs for toolkit components
 * [flux reconcile](flux_reconcile.md)	 - Reconcile sources and resources
 * [flux resume](flux_resume.md)	 - Resume suspended resources
 * [flux suspend](flux_suspend.md)	 - Suspend resources

docs/cmd/flux_logs.md

@@ -0,0 +1,59 @@
+## flux logs
+
+Display formatted logs for toolkit components
+
+### Synopsis
+
+The logs command displays formatted logs from various toolkit components.
+
+```
+flux logs [flags]
+```
+
+### Examples
+
+```
+# Get logs from toolkit components
+	 flux logs
+
+	# Stream logs from toolkit components
+	flux logs --follow
+ 
+	# Get logs from toolkit components in a particular namespace
+	flux logs --flux-namespace my-namespace
+
+	# Get logs for a particular log level
+	flux logs --level=info
+
+	# Filter logs by kind, name, or namespace
+	flux logs --kind=kustomization --name podinfo --namespace default
+    
+```
+
+### Options
+
+```
+  -A, --all-namespaces          displays logs for objects across all namespaces
+      --flux-namespace string   the namespace where the Flux components are running. (default "flux-system")
+  -f, --follow                  Specifies if the logs should be streamed
+  -h, --help                    help for logs
+      --kind string             displays errors of a particular toolkit kind e.g GitRepository
+      --level logLevel          log level, available options are: (debug, info, error)
+      --name string             specifies the name of the object logs to be displayed
+      --tail int                lines of recent log file to display (default -1)
+```
+
+### Options inherited from parent commands
+
+```
+      --context string      kubernetes context to use
+      --kubeconfig string   path to the kubeconfig file (default "~/.kube/config")
+  -n, --namespace string    the namespace scope for this operation (default "flux-system")
+      --timeout duration    timeout for this operation (default 5m0s)
+      --verbose             print generated objects
+```
+
+### SEE ALSO
+
+* [flux](flux.md)	 - Command line utility for assembling Kubernetes CD pipelines
+

mkdocs.yml

@@ -161,6 +161,7 @@ nav:
     - Get images repository: cmd/flux_get_images_repository.md
     - Get images update: cmd/flux_get_images_update.md
     - Install: cmd/flux_install.md
+    - Logs: cmd/flux_logs.md
     - Resume: cmd/flux_resume.md
     - Resume kustomization: cmd/flux_resume_kustomization.md
     - Resume helmrelease: cmd/flux_resume_helmrelease.md