func injectCommand()

in istioctl/cmd/kubeinject.go [508:668]
142 lines of code
21 McCabe index (conditional complexity)

func injectCommand() *cobra.Command {
	var opts clioptions.ControlPlaneOptions
	var centralOpts clioptions.CentralControlPlaneOptions

	injectCmd := &cobra.Command{
		Use:   "kube-inject",
		Short: "Inject Istio sidecar into Kubernetes pod resources",
		Long: `
kube-inject manually injects the Istio sidecar into Kubernetes
workloads. Unsupported resources are left unmodified so it is safe to
run kube-inject over a single file that contains multiple Service,
ConfigMap, Deployment, etc. definitions for a complex application. When in
doubt re-run istioctl kube-inject on deployments to get the most up-to-date changes.

It's best to do kube-inject when the resource is initially created.
`,
		Example: `  # Update resources on the fly before applying.
  kubectl apply -f <(istioctl kube-inject -f <resource.yaml>)

  # Create a persistent version of the deployment with Istio sidecar injected.
  istioctl kube-inject -f deployment.yaml -o deployment-injected.yaml

  # Update an existing deployment.
  kubectl get deployment -o yaml | istioctl kube-inject -f - | kubectl apply -f -

  # Capture cluster configuration for later use with kube-inject
  kubectl -n dubbo-system get cm istio-sidecar-injector  -o jsonpath="{.data.config}" > /tmp/inj-template.tmpl
  kubectl -n dubbo-system get cm istio -o jsonpath="{.data.mesh}" > /tmp/mesh.yaml
  kubectl -n dubbo-system get cm istio-sidecar-injector -o jsonpath="{.data.values}" > /tmp/values.json

  # Use kube-inject based on captured configuration
  istioctl kube-inject -f samples/bookinfo/platform/kube/bookinfo.yaml \
    --injectConfigFile /tmp/inj-template.tmpl \
    --meshConfigFile /tmp/mesh.yaml \
    --valuesFile /tmp/values.json
`,
		RunE: func(c *cobra.Command, _ []string) (err error) {
			if err = validateFlags(); err != nil {
				return err
			}
			var reader io.Reader

			if inFilename == "-" {
				reader = os.Stdin
			} else {
				var in *os.File
				if in, err = os.Open(inFilename); err != nil {
					return err
				}
				reader = in
				defer func() {
					if errClose := in.Close(); errClose != nil {
						log.Errorf("Error: close file from %s, %s", inFilename, errClose)

						// don't overwrite the previous error
						if err == nil {
							err = errClose
						}
					}
				}()
			}

			var writer io.Writer
			if outFilename == "" {
				writer = c.OutOrStdout()
			} else {
				var out *os.File
				if out, err = os.Create(outFilename); err != nil {
					return err
				}
				writer = out
				defer func() {
					if errClose := out.Close(); errClose != nil {
						log.Errorf("Error: close file from %s, %s", outFilename, errClose)

						// don't overwrite the previous error
						if err == nil {
							err = errClose
						}
					}
				}()
			}
			var valuesConfig string
			var sidecarTemplate inject.RawTemplates
			var meshConfig *meshconfig.MeshConfig
			rev := opts.Revision
			// if the revision is "default", render templates with an empty revision
			if rev == tag.DefaultRevisionName {
				rev = ""
			}
			injectorAddress := centralOpts.Xds
			index := strings.IndexByte(injectorAddress, ':')
			if index != -1 {
				injectorAddress = injectorAddress[:index]
			}
			injector, meshConfig, err := setupKubeInjectParameters(&sidecarTemplate, &valuesConfig, rev, injectorAddress)
			if err != nil {
				return err
			}
			if injector.client == nil && meshConfig == nil {
				return fmt.Errorf(
					"failed to get injection config from mutatingWebhookConfigurations and injection configmap - " +
						"check injection configmap or pass --revision flag",
				)
			}
			var warnings []string
			templs, err := inject.ParseTemplates(sidecarTemplate)
			if err != nil {
				return err
			}
			vc, err := inject.NewValuesConfig(valuesConfig)
			if err != nil {
				return err
			}
			retval := inject.IntoResourceFile(injector, templs, vc, rev, meshConfig,
				reader, writer, func(warning string) {
					warnings = append(warnings, warning)
				})
			if len(warnings) > 0 {
				fmt.Fprintln(c.ErrOrStderr())
			}
			for _, warning := range warnings {
				fmt.Fprintln(c.ErrOrStderr(), warning)
			}
			return retval
		},
		PersistentPreRunE: func(c *cobra.Command, args []string) error {
			// istioctl kube-inject is typically redirected to a .yaml file;
			// the default for log messages should be stderr, not stdout
			_ = c.Root().PersistentFlags().Set("log_target", "stderr")

			return c.Parent().PersistentPreRunE(c, args)
		},
	}

	injectCmd.PersistentFlags().StringVar(&meshConfigFile, "meshConfigFile", "",
		"Mesh configuration filename. Takes precedence over --meshConfigMapName if set")
	injectCmd.PersistentFlags().StringVar(&injectConfigFile, "injectConfigFile", "",
		"Injection configuration filename. Cannot be used with --injectConfigMapName")
	injectCmd.PersistentFlags().StringVar(&valuesFile, "valuesFile", "",
		"Injection values configuration filename.")

	injectCmd.PersistentFlags().StringVarP(&inFilename, "filename", "f",
		"", "Input Kubernetes resource filename")
	injectCmd.PersistentFlags().StringVarP(&outFilename, "output", "o",
		"", "Modified output Kubernetes resource filename")
	injectCmd.PersistentFlags().StringVar(&iopFilename, "operatorFileName", "",
		"Path to file containing IstioOperator custom resources. If configs from files like "+
			"meshConfigFile, valuesFile are provided, they will be overridden by iop config values.")

	injectCmd.PersistentFlags().StringVar(&meshConfigMapName, "meshConfigMapName", defaultMeshConfigMapName,
		fmt.Sprintf("ConfigMap name for Istio mesh configuration, key should be %q", configMapKey))
	injectCmd.PersistentFlags().StringVar(&injectConfigMapName, "injectConfigMapName", defaultInjectConfigMapName,
		fmt.Sprintf("ConfigMap name for Istio sidecar injection, key should be %q.", injectConfigMapKey))
	_ = injectCmd.PersistentFlags().MarkHidden("injectConfigMapName")
	injectCmd.PersistentFlags().StringVar(&whcName, "webhookConfig", defaultInjectWebhookConfigName,
		"MutatingWebhookConfiguration name for Istio")
	opts.AttachControlPlaneFlags(injectCmd)
	centralOpts.AttachControlPlaneFlags(injectCmd)
	return injectCmd
}