feat: add --username-infix to scaletest create-users (#28514)

cli/exp_scaletest_createusers.go

@@ -23,6 +23,7 @@ func (r *RootCmd) scaletestCreateUsers() *serpent.Command {
 	var (
 		count                   int64
 		templateAdminPercentage float64
+		usernameInfix           string
 		noCleanup               bool
 
 		tracingFlags    = &scaletestTracingFlags{}
@@ -93,6 +94,15 @@ func (r *RootCmd) scaletestCreateUsers() *serpent.Command {
 
 			th := harness.NewTestHarness(strategy.toStrategy(), cleanupStrategy.toStrategy())
 
+			// The scaletest- root is always kept so the cleanup command still
+			// finds these users; --username-infix is inserted between it and the
+			// random suffix, e.g. --username-infix asdf produces usernames like
+			// scaletest-asdf-<random>-<id>.
+			userPrefix := loadtestutil.ScaleTestPrefix + "-"
+			if usernameInfix != "" {
+				userPrefix += usernameInfix + "-"
+			}
+
 			_, _ = fmt.Fprintln(inv.Stderr, "Creating users...")
 			for i := range count {
 				id := strconv.FormatInt(i, 10)
@@ -110,9 +120,15 @@ func (r *RootCmd) scaletestCreateUsers() *serpent.Command {
 					return xerrors.Errorf("create runner client: %w", err)
 				}
 
-				// Username and email are generated by createusers when left empty.
+				username, email, err := loadtestutil.GenerateUserIdentifierWithPrefix(userPrefix, id)
+				if err != nil {
+					return xerrors.Errorf("generate user identifier: %w", err)
+				}
+
 				config := createusers.Config{
 					OrganizationID: me.OrganizationIDs[0],
+					Username:       username,
+					Email:          email,
 				}
 				if err := config.Validate(); err != nil {
 					return xerrors.Errorf("validate config: %w", err)
@@ -191,6 +207,12 @@ func (r *RootCmd) scaletestCreateUsers() *serpent.Command {
 			Description: "Percentage of users to assign the Template Admin role to (0-100).",
 			Value:       serpent.Float64Of(&templateAdminPercentage),
 		},
+		{
+			Flag:        "username-infix",
+			Env:         "CODER_SCALETEST_CREATE_USERS_USERNAME_INFIX",
+			Description: "Optional infix inserted between the mandatory \"scaletest-\" root and the rest of each generated username. For example --username-infix asdf produces usernames like scaletest-asdf-<random>-<id>; leave empty for the default scaletest-<random>-<id> names. Use it to partition users into disjoint pools that a matching --reuse-users run can select. The scaletest- root is always kept so the cleanup command still discovers the users.",
+			Value:       serpent.StringOf(&usernameInfix),
+		},
 		{
 			Flag:        "no-cleanup",
 			Env:         "CODER_SCALETEST_NO_CLEANUP",

scaletest/loadtestutil/names.go

@@ -21,12 +21,24 @@ const (
 // The username follows the pattern: scaletest-<random>-<id>
 // The email follows the pattern: <random>-<id>@scaletest.local
 func GenerateUserIdentifier(id string) (username, email string, err error) {
+	return GenerateUserIdentifierWithPrefix(ScaleTestPrefix+"-", id)
+}
+
+// GenerateUserIdentifierWithPrefix generates a username and email for scale
+// testing using a caller-supplied username prefix. The username follows the
+// pattern: <prefix><random>-<id>. Callers are expected to keep the "scaletest-"
+// root in prefix so users created with a custom prefix are still discovered by
+// IsScaleTestUser and the scaletest cleanup command; a caller-chosen infix
+// is inserted between the root and the random suffix (for example prefix
+// "scaletest-asdf-" yields scaletest-asdf-<random>-<id>). The email keeps the
+// scaletest domain regardless (<random>-<id>@scaletest.local).
+func GenerateUserIdentifierWithPrefix(prefix, id string) (username, email string, err error) {
 	randStr, err := cryptorand.String(DefaultRandLength)
 	if err != nil {
 		return "", "", err
 	}
 
-	username = fmt.Sprintf("%s-%s-%s", ScaleTestPrefix, randStr, id)
+	username = fmt.Sprintf("%s%s-%s", prefix, randStr, id)
 	email = fmt.Sprintf("%s-%s%s", randStr, id, EmailDomain)
 	return username, email, nil
 }

scaletest/loadtestutil/names_test.go

@@ -0,0 +1,72 @@
+package loadtestutil_test
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	"github.com/coder/coder/v2/scaletest/loadtestutil"
+)
+
+func TestGenerateUserIdentifierWithPrefix(t *testing.T) {
+	t.Parallel()
+
+	const id = "7"
+
+	cases := []struct {
+		name       string
+		prefix     string
+		wantPrefix string
+	}{
+		{
+			name:       "default scaletest prefix",
+			prefix:     loadtestutil.ScaleTestPrefix + "-",
+			wantPrefix: "scaletest-",
+		},
+		{
+			name:       "infix inserted after scaletest root",
+			prefix:     loadtestutil.ScaleTestPrefix + "-notif-",
+			wantPrefix: "scaletest-notif-",
+		},
+	}
+
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+
+			username, email, err := loadtestutil.GenerateUserIdentifierWithPrefix(tc.prefix, id)
+			require.NoError(t, err)
+
+			// username == <prefix><random>-<id>.
+			require.True(t, strings.HasPrefix(username, tc.wantPrefix),
+				"username %q should start with %q", username, tc.wantPrefix)
+			require.True(t, strings.HasSuffix(username, "-"+id),
+				"username %q should end with %q", username, "-"+id)
+
+			randPart := strings.TrimSuffix(strings.TrimPrefix(username, tc.prefix), "-"+id)
+			require.Len(t, randPart, loadtestutil.DefaultRandLength)
+
+			// The email reuses the same random-id and keeps the scaletest domain.
+			require.Equal(t, randPart+"-"+id+loadtestutil.EmailDomain, email)
+
+			// Custom prefixes that keep the scaletest- root stay discoverable.
+			require.True(t, loadtestutil.IsScaleTestUser(username, email))
+		})
+	}
+}
+
+func TestGenerateUserIdentifierUsesDefaultPrefix(t *testing.T) {
+	t.Parallel()
+
+	username, email, err := loadtestutil.GenerateUserIdentifier("3")
+	require.NoError(t, err)
+
+	require.True(t, strings.HasPrefix(username, loadtestutil.ScaleTestPrefix+"-"),
+		"username %q should start with the scaletest- root", username)
+	require.True(t, strings.HasSuffix(username, "-3"),
+		"username %q should end with the id", username)
+	require.True(t, strings.HasSuffix(email, "-3"+loadtestutil.EmailDomain),
+		"email %q should end with the id and scaletest domain", email)
+	require.True(t, loadtestutil.IsScaleTestUser(username, email))
+}