feat: sanitise the domain name before launching the tui (#90)

.github/workflows/docs.yml

@@ -41,38 +41,20 @@ jobs:
         with:
           fetch-depth: 0
 
-      - name: Set up Python runtime
-        uses: actions/setup-python@v4
+      - name: GHCR Login
+        uses: docker/login-action@v2
         with:
-          python-version: 3.x
+          registry: ghcr.io
+          username: ${{ github.repository_owner }}
+          password: ${{ secrets.GH_GHCR }}
 
-      - name: Set up build cache
-        uses: actions/cache@v3
-        id: cache
-        with:
-          key: ${{ runner.os }}-${{ hashFiles('.cache/**') }}
-          path: .cache
-
-      - name: Install Python dependencies
-        run: |
-          pip install \
-            "mkdocs-git-committers-plugin-2>=0.4.3" \
-            "mkdocs-git-revision-date-localized-plugin>=1.0" \
-            "mkdocs-minify-plugin>=0.3" \
-            "mkdocs-redirects>=1.0"
-
-      - name: Install MkDocs Insiders
-        if: github.event.repository.fork == false
-        env:
-          GH_TOKEN: ${{ secrets.GH_MKDOCS }}
-        run: |
-          pip install git+https://${GH_TOKEN}@github.com/squidfunk/mkdocs-material-insiders.git
+      - run: docker pull ghcr.io/purpleclay/mkdocs-material-insiders
 
       - name: Build
-        run: mkdocs build
         env:
           GH_TOKEN: ${{ secrets.GH_MKDOCS }}
           GH_GOOGLE_ANALYTICS_KEY: ${{ secrets.GH_GOOGLE_ANALYTICS_KEY }}
+        run: docker run --rm -i -e GH_TOKEN=${GH_TOKEN} -e GH_GOOGLE_ANALYTICS_KEY=${GH_GOOGLE_ANALYTICS_KEY} -v ${PWD}:/docs ghcr.io/purpleclay/mkdocs-material-insiders build
 
       - name: HTML Test
         uses: wjdp/htmltest-action@master
@@ -94,6 +76,4 @@ jobs:
         env:
           GH_TOKEN: ${{ secrets.GH_MKDOCS }}
           GH_GOOGLE_ANALYTICS_KEY: ${{ secrets.GH_GOOGLE_ANALYTICS_KEY }}
-        run: |
-          mkdocs gh-deploy --force
-          mkdocs --version
+        run: docker run --rm -i -e GH_TOKEN=${GH_TOKEN} -e GH_GOOGLE_ANALYTICS_KEY=${GH_GOOGLE_ANALYTICS_KEY} -v ${PWD}:/docs ghcr.io/purpleclay/mkdocs-material-insiders gh-deploy --force

.golangci.yml

@@ -4,7 +4,6 @@ run:
 linters:
   disable-all: true
   enable:
-    - deadcode
     - dupl
     - gofumpt
     - goimports
@@ -15,9 +14,7 @@ linters:
     - nakedret
     - revive
     - staticcheck
-    - structcheck
     - unused
-    - varcheck
 
 linters-settings:
   dupl:

.sonarcloud.properties

@@ -0,0 +1,2 @@
+# Exclude tests from copy-paste detection as SonarCloud doesn't appear to like table driven tests
+sonar.cpd.exclusions=**/*_test.go

README.md

@@ -1,6 +1,6 @@
 # dns53
 
-Dynamic DNS within Amazon Route53. Expose your EC2 quickly, easily and privately.
+Dynamic DNS within Amazon Route53. Expose your EC2 quickly, easily, and privately.
 
 [![Build status](https://img.shields.io/github/workflow/status/purpleclay/dns53/ci?style=flat-square&logo=go)](https://github.com/purpleclay/dns53/actions?workflow=ci)
 [![License MIT](https://img.shields.io/badge/license-MIT-blue.svg?style=flat-square)](/LICENSE)

cmd/root.go

@@ -23,16 +23,20 @@ SOFTWARE.
 package cmd
 
 import (
+	"bytes"
 	"context"
 	"errors"
 	"io"
+	"regexp"
 	"strings"
+	"text/template"
 
 	"github.com/aws/aws-sdk-go-v2/aws"
 	"github.com/aws/aws-sdk-go-v2/config"
 	awsimds "github.com/aws/aws-sdk-go-v2/feature/ec2/imds"
 	awsr53 "github.com/aws/aws-sdk-go-v2/service/route53"
 	tea "github.com/charmbracelet/bubbletea"
+	"github.com/gobeam/stringy"
 	"github.com/purpleclay/dns53/internal/imds"
 	"github.com/purpleclay/dns53/internal/r53"
 	"github.com/purpleclay/dns53/internal/tui"
@@ -66,7 +70,11 @@ type globalOptions struct {
 	AWSProfile string
 }
 
-var globalOpts = &globalOptions{}
+var (
+	globalOpts = &globalOptions{}
+
+	domainRegex = regexp.MustCompile("[^a-zA-Z0-9-.]+")
+)
 
 type options struct {
 	phzID      string
@@ -76,6 +84,10 @@ type options struct {
 func Execute(out io.Writer) error {
 	opts := options{}
 
+	// Capture in PreRun lifecycle
+	var cfg aws.Config
+	var metadata imds.Metadata
+
 	rootCmd := &cobra.Command{
 		Use: "dns53",
 		Short: `Dynamic DNS within Amazon Route 53. Expose your EC2 quickly, easily and privately within a Route 
@@ -84,31 +96,34 @@ func Execute(out io.Writer) error {
 		Example:       examples,
 		SilenceUsage:  true,
 		SilenceErrors: true,
-		RunE: func(cmd *cobra.Command, args []string) error {
-			cfg, err := awsConfig(globalOpts)
+		PreRunE: func(cmd *cobra.Command, args []string) error {
+			var err error
+
+			cfg, err = awsConfig(globalOpts)
 			if err != nil {
 				return err
 			}
 
-			// If a custom domain name has been provided, check that it can be resolved from IMDS
 			imdsClient := imds.NewFromAPI(awsimds.NewFromConfig(cfg))
+			if metadata, err = imdsClient.InstanceMetadata(context.Background()); err != nil {
+				return err
+			}
 
-			if opts.domainName != "" {
-				if err := domainNameSupported(opts.domainName, imdsClient); err != nil {
-					return err
-				}
+			if opts.domainName == "" {
+				return nil
 			}
 
-			model, err := tui.Dashboard(tui.DashboardOptions{
+			opts.domainName, err = resolveDomainName(opts.domainName, metadata)
+			return err
+		},
+		RunE: func(cmd *cobra.Command, args []string) error {
+			model := tui.Dashboard(tui.DashboardOptions{
 				R53Client:  r53.NewFromAPI(awsr53.NewFromConfig(cfg)),
-				IMDSClient: imdsClient,
+				Metadata:   metadata,
 				Version:    version,
 				PhzID:      opts.phzID,
 				DomainName: opts.domainName,
 			})
-			if err != nil {
-				return err
-			}
 
 			return tea.NewProgram(model, tea.WithAltScreen()).Start()
 		},
@@ -143,23 +158,45 @@ func awsConfig(opts *globalOptions) (aws.Config, error) {
 	return config.LoadDefaultConfig(context.Background(), optsFn...)
 }
 
-func domainNameSupported(domain string, imdsClient *imds.Client) error {
+func resolveDomainName(domain string, metadata imds.Metadata) (string, error) {
 	dmn := strings.ReplaceAll(domain, " ", "")
-	if strings.Contains(dmn, "{{.Name}}") {
-		metadata, err := imdsClient.InstanceMetadata(context.Background())
-		if err != nil {
-			return err
-		}
 
+	if strings.Contains(dmn, "{{.Name}}") {
 		if metadata.Name == "" {
-			return errors.New(`to use metadata within a custom domain name, please enable IMDS instance tags support 
+			return "", errors.New(`to use metadata within a custom domain name, please enable IMDS instance tags support
 for your EC2 instance:
 
   $ dns53 imds --instance-metadata-tags on
 
-Or read the official AWS documentation at: 
+Or read the official AWS documentation at:
 https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/Using_Tags.html#allow-access-to-tags-in-IMDS`)
 		}
+
+		name := stringy.New(metadata.Name)
+		metadata.Name = name.KebabCase().ToLower()
+	}
+
+	// Sanitise the copy of the metadata before resolving the template
+	metadata.IPv4 = strings.ReplaceAll(metadata.IPv4, ".", "-")
+
+	// Execute the domain template
+	tmpl, err := template.New("domain").Parse(domain)
+	if err != nil {
+		return "", err
+	}
+
+	var out bytes.Buffer
+	if err := tmpl.Execute(&out, metadata); err != nil {
+		return "", err
 	}
-	return nil
+	dmn = out.String()
+
+	// Final tidy up of the domain
+	dmn = strings.ReplaceAll(dmn, "--", "-")
+	dmn = strings.ReplaceAll(dmn, "..", ".")
+	dmn = strings.Trim(dmn, "-")
+	dmn = strings.Trim(dmn, ".")
+	dmn = domainRegex.ReplaceAllString(dmn, "")
+
+	return dmn, nil
 }

cmd/root_test.go

@@ -26,7 +26,6 @@ import (
 	"testing"
 
 	"github.com/purpleclay/dns53/internal/imds"
-	"github.com/purpleclay/dns53/internal/imds/imdsstub"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
@@ -41,41 +40,101 @@ func TestAWSConfig(t *testing.T) {
 	assert.Equal(t, "eu-west-2", cfg.Region)
 }
 
-func TestDomainNameSupported(t *testing.T) {
+func TestResolveDomainName(t *testing.T) {
+	metadata := imds.Metadata{
+		Name: "my-ec2",
+	}
+
 	tests := []struct {
-		name   string
-		domain string
+		name     string
+		domain   string
+		expected string
 	}{
 		{
-			name:   "NoTemplating",
-			domain: "custom.domain",
+			name:     "NoTemplating",
+			domain:   "custom.domain",
+			expected: "custom.domain",
+		},
+		{
+			name:     "WithNameField",
+			domain:   "custom.{{.Name}}",
+			expected: "custom.my-ec2",
 		},
 		{
-			name:   "WithNameField",
-			domain: "custom.{{.Name}}",
+			name:     "WithNameFieldSpaces",
+			domain:   "custom.{{ .Name }}",
+			expected: "custom.my-ec2",
 		},
 		{
-			name:   "WithNameFieldSpaces",
-			domain: "custom.{{ .Name }}",
+			name:     "ReplacesDoubleHyphens",
+			domain:   "another--custom.domain",
+			expected: "another-custom.domain",
+		},
+		{
+			name:     "ReplacesDoubleDots",
+			domain:   "my-custom123..domain",
+			expected: "my-custom123.domain",
+		},
+		{
+			name:     "RemoveLeadingTrailingHyphen",
+			domain:   "-this-is-a-custom.domain-",
+			expected: "this-is-a-custom.domain",
+		},
+		{
+			name:     "RemoveLeadingTrailingDot",
+			domain:   ".a-custom.domain.",
+			expected: "a-custom.domain",
+		},
+		{
+			name:     "TrimUnsupportedCharacters",
+			domain:   "custom@#.doma**in-123",
+			expected: "custom.domain-123",
 		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			err := domainNameSupported(tt.domain, imds.NewFromAPI(imdsstub.New(t)))
+			domain, err := resolveDomainName(tt.domain, metadata)
 
 			require.NoError(t, err)
+			require.Equal(t, tt.expected, domain)
 		})
 	}
 }
 
-func TestDomainNameSupportedNoInstanceTags(t *testing.T) {
-	err := domainNameSupported("custom.{{.Name}}", imds.NewFromAPI(imdsstub.NewWithoutTags(t)))
+func TestResolveDomainNameNoInstanceTags(t *testing.T) {
+	_, err := resolveDomainName("custom.{{.Name}}", imds.Metadata{})
 
-	assert.EqualError(t, err, `to use metadata within a custom domain name, please enable IMDS instance tags support 
+	assert.EqualError(t, err, `to use metadata within a custom domain name, please enable IMDS instance tags support
 for your EC2 instance:
 
   $ dns53 imds --instance-metadata-tags on
 
-Or read the official AWS documentation at: 
+Or read the official AWS documentation at:
 https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/Using_Tags.html#allow-access-to-tags-in-IMDS`)
 }
+
+func TestResolveDomainNameTransformsNameTagToKebabCase(t *testing.T) {
+	domain, err := resolveDomainName("first.custom.{{.Name}}", imds.Metadata{Name: "MyEc2 123"})
+
+	require.NoError(t, err)
+	assert.Equal(t, "first.custom.my-ec2-123", domain)
+}
+
+func TestResolveDomainNameStripsLeadingTrailingHyphenFromNameTag(t *testing.T) {
+	domain, err := resolveDomainName("second.custom.{{.Name}}", imds.Metadata{Name: "-MyEc2 123-"})
+
+	require.NoError(t, err)
+	assert.Equal(t, "second.custom.my-ec2-123", domain)
+}
+
+func TestResolveDomainNameInvalidGoTemplate(t *testing.T) {
+	_, err := resolveDomainName("custom.{{.Name}", imds.Metadata{Name: "MyEc2 123"})
+
+	assert.Error(t, err)
+}
+
+func TestResolveDomainNameUnrecognisedTemplateFields(t *testing.T) {
+	_, err := resolveDomainName("custom.{{.Unknown}}", imds.Metadata{})
+
+	assert.Error(t, err)
+}

docs/configure/custom-domain.md

@@ -23,3 +23,16 @@ A templated domain leverages the text templating capabilities of the Go language
 ```sh
 dns53 --domain-name "{{.IPv4}}.{{.Region}}"
 ```
+
+## Domain Validation
+
+A custom domain must be valid before assigning it to your EC2 instance. A series of checks must pass.
+
+A domain must:
+
+- not contain leading or trailing hyphens (`-`) and dots (`.`)
+- not contain consecutive hyphens (`--`) or dots (`..`)
+- not contain whitespace (` `)
+- only contain valid characters from the sequence `[A-Za-z0-9-.]`
+
+`dns53` will automatically clean any domain name in an attempt to enforce these validation checks.

go.mod

@@ -11,6 +11,7 @@ require (
 	github.com/charmbracelet/bubbles v0.14.0
 	github.com/charmbracelet/bubbletea v0.22.1
 	github.com/charmbracelet/lipgloss v0.6.0
+	github.com/gobeam/stringy v0.0.5
 	github.com/muesli/mango-cobra v1.2.0
 	github.com/muesli/roff v0.1.0
 	github.com/purpleclay/testcontainers-imds v0.7.0

go.sum

@@ -344,6 +344,8 @@ github.com/go-redis/redis v6.15.9+incompatible/go.mod h1:NAIEuMOZ/fxfXJIrKDQDz8w
 github.com/go-sql-driver/mysql v1.6.0 h1:BCTh4TKNUYmOmMUcQ3IipzF5prigylS7XXjEkfCHuOE=
 github.com/go-sql-driver/mysql v1.6.0/go.mod h1:DCzpHaOWr8IXmIStZouvnhqoel9Qv2LBy8hT2VhHyBg=
 github.com/go-stack/stack v1.8.0/go.mod h1:v0f6uXyyMGvRgIKkXu+yp6POWl0qKG85gN/melR3HDY=
+github.com/gobeam/stringy v0.0.5 h1:TvxQGSAqr/qF0SBVxa8Q67WWIo7bCWS0bM101WOd52g=
+github.com/gobeam/stringy v0.0.5/go.mod h1:W3620X9dJHf2FSZF5fRnWekHcHQjwmCz8ZQ2d1qloqE=
 github.com/goccy/go-json v0.9.7 h1:IcB+Aqpx/iMHu5Yooh7jEzJk1JZ7Pjtmys2ukPr7EeM=
 github.com/goccy/go-json v0.9.7/go.mod h1:6MelG93GURQebXPDq3khkgXZkazVtN9CRI+MGFi0w8I=
 github.com/godbus/dbus v0.0.0-20151105175453-c7fdd8b5cd55/go.mod h1:/YcGZj5zSblfDWMMoOzV4fas9FZnQYTkDnsGvmh2Grw=