let users pull VM images from remote location on start

Adds a new option "--pull-template". When specified, every base image
is pulled from the given remote location on first use. The template
given is used to get the remote location used in

  virter image pull <base> <remote>

It accepts a go template string. A user can use "{{ .Image }}" to generically
specify a pull location based on the name of the base image.

Author: WanzenBug

cmd/schedule.go

@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"net"
 	"os/exec"
+	"text/template"
 
 	log "github.com/sirupsen/logrus"
 )
@@ -44,6 +45,7 @@ const (
 
 type suiteState struct {
 	networks   map[string]*networkState
+	baseImage  map[string]imageStage
 	imageStage map[string]imageStage
 	runStage   map[string]runStage
 	runResults map[string]testResult
@@ -92,6 +94,7 @@ func initializeState(suiteRun *testSuiteRun) *suiteState {
 
 	state := suiteState{
 		networks:   make(map[string]*networkState),
+		baseImage:  make(map[string]imageStage),
 		imageStage: make(map[string]imageStage),
 		runStage:   make(map[string]runStage),
 		runResults: make(map[string]testResult),
@@ -102,11 +105,18 @@ func initializeState(suiteRun *testSuiteRun) *suiteState {
 		state.runStage[run.testID] = runNew
 	}
 
+	initialBaseImageState := imageReady
+	if suiteRun.pullImageTemplate != nil {
+		initialBaseImageState = imageNone
+	}
+
 	initialImageStage := imageReady
 	if suiteRun.vmSpec.ProvisionFile != "" {
 		initialImageStage = imageNone
 	}
 	for _, v := range suiteRun.vmSpec.VMs {
+		state.baseImage[v.BaseImage] = initialBaseImageState
+
 		state.imageStage[v.ID()] = initialImageStage
 	}
 
@@ -185,6 +195,10 @@ func runStopping(suiteRun *testSuiteRun, state *suiteState) bool {
 	}
 
 	for _, v := range suiteRun.vmSpec.VMs {
+		if state.baseImage[v.BaseImage] == imageError {
+			return true
+		}
+
 		if state.imageStage[v.ID()] == imageError {
 			return true
 		}
@@ -227,7 +241,7 @@ func chooseNextAction(suiteRun *testSuiteRun, state *suiteState) action {
 	}
 
 	for i, v := range suiteRun.vmSpec.VMs {
-		if state.imageStage[v.ID()] == imageNone {
+		if state.baseImage[v.BaseImage] == imageNone || state.imageStage[v.ID()] == imageNone {
 			return nextActionProvision(suiteRun, state, &suiteRun.vmSpec.VMs[i])
 		}
 	}
@@ -264,6 +278,10 @@ func runBetter(state *suiteState, a *testRun, b testRun) bool {
 
 func allImagesReady(state *suiteState, run *testRun) bool {
 	for _, v := range run.vms {
+		if state.baseImage[v.BaseImage] != imageReady {
+			return false
+		}
+
 		if state.imageStage[v.ID()] != imageReady {
 			return false
 		}
@@ -389,6 +407,14 @@ func getIDs(suiteRun *testSuiteRun, state *suiteState, n int) []int {
 }
 
 func nextActionProvision(suiteRun *testSuiteRun, state *suiteState, v *vm) action {
+	if state.baseImage[v.BaseImage] == imageNone {
+		return &pullImageAction{Image: v.BaseImage, PullTemplate: suiteRun.pullImageTemplate}
+	}
+
+	if state.baseImage[v.BaseImage] != imageReady {
+		return nil
+	}
+
 	network := accessNetwork(false)
 	networkName := findReadyNetwork(state, nil, network, true)
 	if networkName == "" {
@@ -475,6 +501,33 @@ func (a *performTestAction) updatePost(state *suiteState) {
 	}
 }
 
+type pullImageAction struct {
+	Image        string
+	PullTemplate *template.Template
+	err          error
+}
+
+func (b *pullImageAction) name() string {
+	return fmt.Sprintf("Pull base image '%s'", b.Image)
+}
+
+func (b *pullImageAction) updatePre(state *suiteState) {
+	state.baseImage[b.Image] = imageProvision
+}
+
+func (b *pullImageAction) exec(ctx context.Context, suiteRun *testSuiteRun) {
+	b.err = pullImage(ctx, suiteRun, b.Image, b.PullTemplate)
+}
+
+func (b *pullImageAction) updatePost(state *suiteState) {
+	if b.err == nil {
+		state.baseImage[b.Image] = imageReady
+	} else {
+		state.baseImage[b.Image] = imageError
+		state.errors = append(state.errors, fmt.Errorf("pull image %s: %w", b.Image, b.err))
+	}
+}
+
 type provisionImageAction struct {
 	v           *vm
 	id          int

cmd/vm.go

@@ -9,6 +9,7 @@ import (
 	"strconv"
 	"strings"
 	"sync"
+	"text/template"
 	"time"
 
 	log "github.com/sirupsen/logrus"
@@ -52,6 +53,37 @@ func testIDString(test string, vmCount int, variantName string, testIndex int) s
 	return fmt.Sprintf("%s-%d-%s-%d", test, vmCount, variantName, testIndex)
 }
 
+func pullImage(ctx context.Context, suiteRun *testSuiteRun, image string, templ *template.Template) error {
+	logger := log.WithFields(log.Fields{
+		"Action": "Pull",
+		"Image":  image,
+	})
+
+	errPath := filepath.Join(suiteRun.outDir, "provision-log", fmt.Sprintf("%s-pull.log", image))
+	argv := []string{"virter", "image", "pull", image}
+
+	if templ != nil {
+		var buf strings.Builder
+		err := templ.Execute(&buf, map[string]string{
+			"Image": image,
+		})
+		if err != nil {
+			return err
+		}
+
+		argv = append(argv, buf.String())
+	}
+
+	cmd := exec.CommandContext(ctx, argv[0], argv[1:]...)
+
+	log.Debugf("EXECUTING: %s", argv)
+	start := time.Now()
+	err := cmdStderrTerm(ctx, logger, errPath, cmd)
+	log.Debugf("EXECUTIONTIME: Pull image %s: %v", image, time.Since(start))
+
+	return err
+}
+
 func provisionImage(ctx context.Context, suiteRun *testSuiteRun, nr int, v *vm, networkName string) error {
 	newImageName := suiteRun.vmSpec.ImageName(v)
 	logger := log.WithFields(log.Fields{

cmd/vmshed.go

@@ -12,6 +12,7 @@ import (
 	"path/filepath"
 	"sort"
 	"strings"
+	"text/template"
 	"time"
 
 	"github.com/BurntSushi/toml"
@@ -93,6 +94,7 @@ type testSuiteRun struct {
 	failTest          bool
 	printErrorDetails bool
 	logFormatVirter   string
+	pullImageTemplate *template.Template
 }
 
 type testConfig struct {
@@ -103,6 +105,32 @@ type testConfig struct {
 	repeats    int
 }
 
+type TemplateFlag struct {
+	*template.Template
+}
+
+func (t *TemplateFlag) String() string {
+	if t.Template != nil {
+		return t.Template.Tree.Root.String()
+	} else {
+		return ""
+	}
+}
+
+func (t *TemplateFlag) Set(s string) error {
+	parsed, err := template.New("image").Parse(s)
+	if err != nil {
+		return err
+	}
+
+	t.Template = parsed
+	return nil
+}
+
+func (t *TemplateFlag) Type() string {
+	return "template"
+}
+
 // Execute runs vmshed
 func Execute() {
 	log.SetFormatter(VmshedStandardLogFormatter())
@@ -133,6 +161,7 @@ func rootCommand() *cobra.Command {
 	var errorDetails bool
 	var firstv4Subnet string
 	var firstv6Subnet string
+	var pullImageTemplate TemplateFlag
 
 	rootCmd := &cobra.Command{
 		Use:   "vmshed",
@@ -216,6 +245,7 @@ current user.`,
 			suiteRun.firstV4Net = firstV4Net
 			suiteRun.firstV6Net = firstV6Net
 			suiteRun.logFormatVirter = logFormatVirter
+			suiteRun.pullImageTemplate = pullImageTemplate.Template
 
 			ctx, cancel := signal.NotifyContext(context.Background(), unix.SIGINT, unix.SIGTERM)
 			defer cancel()
@@ -256,6 +286,7 @@ current user.`,
 	rootCmd.Flags().BoolVarP(&errorDetails, "error-details", "", true, "Show all test error logs at the end of the run")
 	rootCmd.Flags().StringVarP(&firstv4Subnet, "first-subnet", "", "10.224.0.0/24", "The first subnet to use for VMs. If more virtual networks are required, the next higher network of the same size will be used")
 	rootCmd.Flags().StringVarP(&firstv6Subnet, "first-v6-subnet", "", "fd62:a80c:412::/64", "The first ipv6 subnet to use for VMs. If more virtual networks are required, the next higher network of the same size will be used")
+	rootCmd.Flags().VarP(&pullImageTemplate, "pull-template", "", "Where to pull the base images from. Accepts a go template string, allowing usage like 'registry.example.com/vm/{{ .Image }}:latest'")
 	return rootCmd
 }