virter: pass-through exit code from provisioning

When a provisioning step fails, it may be helpful to the caller of
virter to know the exit code of the script.

So, if an SSH or container provisioning step fails with an exit code,
pass it through to the CLI, exiting from the virter process with the
same exit code.

Author: chrboe

cmd/image_build.go

@@ -223,7 +223,7 @@ func imageBuildCommand() *cobra.Command {
 
 			err = v.ImageBuild(ctx, tools, vmConfig, getReadyConfig(), buildConfig, virter.WithProgress(DefaultProgressFormat(p)))
 			if err != nil {
-				log.Fatalf("Failed to build image: %v", err)
+				logProvisioningErrorAndExit(err)
 			}
 
 			if push {

cmd/vm_exec.go

@@ -2,9 +2,13 @@ package cmd
 
 import (
 	"context"
+	"errors"
 	"fmt"
+	"os"
 	"strings"
 
+	"golang.org/x/crypto/ssh"
+
 	log "github.com/sirupsen/logrus"
 
 	"github.com/LINBIT/containerapi"
@@ -16,6 +20,23 @@ import (
 	"github.com/spf13/cobra"
 )
 
+// logProvisioningErrorAndExit logs an error from a virter.VMExec* function and exits with the appropriate exit code.
+// If the error is from a failed SSH or container provisioning step, the exit code is the exit code
+// of the respective command.
+// Otherwise, the exit code is 1.
+func logProvisioningErrorAndExit(err error) {
+	log.Errorf("Failed to build image: %v", err)
+	var sshErr *ssh.ExitError
+	if errors.As(err, &sshErr) {
+		os.Exit(sshErr.ExitStatus())
+	}
+	var containerErr *virter.ContainerExitError
+	if errors.As(err, &containerErr) {
+		os.Exit(containerErr.Status)
+	}
+	os.Exit(1)
+}
+
 func vmExecCommand() *cobra.Command {
 	var provisionFile string
 	var provisionOverrides []string
@@ -35,7 +56,7 @@ func vmExecCommand() *cobra.Command {
 				OverridePullPolicy: containerPullPolicy,
 			}
 			if err := execProvision(cmd.Context(), provOpt, args); err != nil {
-				log.Fatal(err)
+				logProvisioningErrorAndExit(err)
 			}
 		},
 		ValidArgsFunction: suggestVmNames,

doc/provisioning.md

@@ -16,6 +16,8 @@ It can also be applied to one or multiple already running VMs:
 $ virter vm exec -p provisioning.toml centos-1 centos-2 centos-3
 ```
 
+If a container or shell provisioning step fails, the virter process will exit with the same exit code as the provisioning script.
+
 ## Provisioning types
 
 The following provisioning types are supported.

internal/virter/container.go

@@ -26,6 +26,14 @@ const (
 	colorReset   = "\u001b[0m"
 )
 
+type ContainerExitError struct {
+	Status int
+}
+
+func (e *ContainerExitError) Error() string {
+	return fmt.Sprintf("container exited with status %d", e.Status)
+}
+
 func containerRun(ctx context.Context, containerProvider containerapi.ContainerProvider, containerCfg *containerapi.ContainerConfig, vmNames []string, vmSSHUserNames []string, vmIPs []string, keyStore sshkeys.KeyStore, knownHosts sshkeys.KnownHosts, copyStep *ProvisionContainerCopyStep) error {
 	// This is roughly equivalent to
 	// docker run --rm --network=host -e TARGETS=$vmIPs -e SSH_PRIVATE_KEY="$sshPrivateKey" $dockerImageName
@@ -192,13 +200,15 @@ func logLines(wg *sync.WaitGroup, vm string, stderr bool, r io.Reader) {
 	}
 }
 
+// containerWait waits for a container to exit.
+// If the container exits with a non-zero exit code, a ContainerExitError is returned.
 func containerWait(statusCh <-chan int64, errCh <-chan error) error {
 	select {
 	case err := <-errCh:
 		return fmt.Errorf("error waiting for container: %w", err)
 	case status := <-statusCh:
 		if status != 0 {
-			return fmt.Errorf("container returned non-zero exit code %d", status)
+			return &ContainerExitError{Status: int(status)}
 		}
 		return nil
 	}