Validate application names so that API calls and Docker build doesn't… (

#296)

* Validate application names so that API calls and Docker build doesn't fail later

cmd/meroxa/root/apps/init.go

@@ -5,6 +5,8 @@ import (
 	"errors"
 	"fmt"
 	"os/exec"
+	"regexp"
+	"strings"
 
 	"github.com/meroxa/cli/cmd/meroxa/builder"
 	turbineCLI "github.com/meroxa/cli/cmd/meroxa/turbine_cli"
@@ -84,11 +86,34 @@ func (i *Init) GitInit(ctx context.Context, path string) error {
 	return nil
 }
 
+func validateAppName(name string) (string, error) {
+	var err error
+
+	// must be lowercase because of reusing the name for the Docker image
+	name = strings.ToLower(name)
+
+	// Platform API requires the first character be a letter and
+	// that the whole name be alphanumeric except for '-' as separators.
+	r := regexp.MustCompile(`^([a-z][a-z0-9-]*)$`)
+	matches := r.FindStringSubmatch(name)
+	if len(matches) == 0 {
+		err = fmt.Errorf(
+			"invalid application name: %s;"+
+				" should start with a letter, be alphanumeric, and only have dashes as separators",
+			name)
+	}
+	return name, err
+}
+
 func (i *Init) Execute(ctx context.Context) error {
 	name := i.args.appName
 	lang := i.flags.Lang
 
-	var err error
+	name, err := validateAppName(name)
+	if err != nil {
+		return err
+	}
+
 	i.path, err = turbineCLI.GetPath(i.flags.Path)
 	if err != nil {
 		return err

cmd/meroxa/root/apps/init_test.go

@@ -3,6 +3,7 @@ package apps
 import (
 	"context"
 	"errors"
+	"fmt"
 	"os"
 	"path/filepath"
 	"testing"
@@ -205,3 +206,58 @@ func TestGoInit(t *testing.T) {
 		})
 	}
 }
+
+func TestAppNameValidation(t *testing.T) {
+	tests := []struct {
+		desc       string
+		inputName  string
+		outputName string
+		err        error
+	}{
+		{
+			desc:       "Valid app name",
+			inputName:  "perfect-name",
+			outputName: "perfect-name",
+			err:        nil,
+		},
+		{
+			desc:       "Valid capitalized app name",
+			inputName:  "Perfect-name",
+			outputName: "perfect-name",
+			err:        nil,
+		},
+		{
+			desc:       "Invalid app name - leading number",
+			inputName:  "3otherwisegoodname",
+			outputName: "",
+			err: fmt.Errorf("invalid application name: %s; should start with a letter, be alphanumeric,"+
+				" and only have dashes as separators", "3otherwisegoodname"),
+		},
+		{
+			desc:       "Invalid app name - invalid characters",
+			inputName:  "!ch@os",
+			outputName: "",
+			err: fmt.Errorf("invalid application name: %s; should start with a letter, be alphanumeric,"+
+				" and only have dashes as separators", "!ch@os"),
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.desc, func(t *testing.T) {
+			output, err := validateAppName(tt.inputName)
+			if err != nil {
+				if tt.err == nil {
+					t.Fatalf("unexpected error \"%s\"", err)
+				} else if tt.err.Error() != err.Error() {
+					t.Fatalf("expected \"%s\" got \"%s\"", tt.err, err)
+				}
+			}
+
+			if err == nil && tt.err == nil {
+				if output != tt.outputName {
+					t.Fatalf("expected \"%s\" got \"%s\"", tt.outputName, output)
+				}
+			}
+		})
+	}
+}