refactor: simplify dockerignore parser

buildkit/frontend.go

@@ -1,3 +1,4 @@
+// for platforms: used by `ghcr.io/railwayapp/railpack-frontend` to accept railpack plans via BuildKit
 package buildkit
 
 import (

core/generate/context.go

@@ -70,15 +70,16 @@ func NewGenerateContext(app *a.App, env *a.Environment, config *config.Config, l
 		return nil, err
 	}
 
-	dockerignoreCtx := plan.NewDockerignoreContext(app)
-	excludes, includes, err := dockerignoreCtx.ParseWithLogging(logger)
+	dockerignoreCtx, err := plan.NewDockerignoreContext(app)
 	if err != nil {
 		return nil, fmt.Errorf("failed to parse .dockerignore: %w", err)
 	}
-
-	if excludes != nil || includes != nil {
-		log.Debugf("Dockerignore exclude patterns: %v", excludes)
-		log.Debugf("Dockerignore include patterns: %v", includes)
+
+	if dockerignoreCtx.HasFile {
+		logger.LogInfo("Found .dockerignore file, applying filters")
+
+		log.Debugf("Dockerignore exclude patterns: %v", dockerignoreCtx.Excludes)
+		log.Debugf("Dockerignore include patterns: %v", dockerignoreCtx.Includes)
 	}
 
 	ctx := &GenerateContext{
@@ -97,7 +98,7 @@ func NewGenerateContext(app *a.App, env *a.Environment, config *config.Config, l
 
 	ctx.applyPackagesFromConfig()
 
-	if excludes != nil || includes != nil {
+	if dockerignoreCtx.HasFile {
 		ctx.Metadata.SetBool("dockerIgnore", true)
 	}
 
@@ -268,12 +269,11 @@ func (c *GenerateContext) applyConfig() {
 func (c *GenerateContext) NewLocalLayer() plan.Layer {
 	layer := plan.NewLocalLayer()
 
-	excludes, includes, _ := c.dockerignoreCtx.Parse()
-	if len(includes) > 0 {
-		layer.Filter.Include = utils.RemoveDuplicates(append(layer.Filter.Include, includes...))
+	if len(c.dockerignoreCtx.Includes) > 0 {
+		layer.Filter.Include = append(layer.Filter.Include, c.dockerignoreCtx.Includes...)
 	}
-	if len(excludes) > 0 {
-		layer.Filter.Exclude = utils.RemoveDuplicates(append(layer.Filter.Exclude, excludes...))
+	if len(c.dockerignoreCtx.Excludes) > 0 {
+		layer.Filter.Exclude = append(layer.Filter.Exclude, c.dockerignoreCtx.Excludes...)
 	}
 
 	return layer

core/generate/context_test.go

@@ -154,9 +154,8 @@ func TestGenerateContextDockerignore(t *testing.T) {
 		require.NotNil(t, ctx.dockerignoreCtx)
 
 		// Verify parsing works with no file present
-		excludes, includes, _ := ctx.dockerignoreCtx.Parse()
-		require.Nil(t, excludes)
-		require.Nil(t, includes)
+		require.Nil(t, ctx.dockerignoreCtx.Excludes)
+		require.Nil(t, ctx.dockerignoreCtx.Includes)
 	})
 
 	t.Run("context creation fails with invalid dockerignore", func(t *testing.T) {

core/plan/dockerignore.go

@@ -3,8 +3,12 @@ package plan
 import (
 	"strings"
 
-	"github.com/moby/patternmatcher/ignorefile"
 	"github.com/railwayapp/railpack/core/app"
+	"github.com/railwayapp/railpack/internal/utils"
+
+	// this is the native dockerignore parser used by buildkit
+	// https://github.com/moby/buildkit/blob/master/frontend/dockerfile/dockerignore/dockerignore_deprecated.go
+	"github.com/moby/patternmatcher/ignorefile"
 )
 
 // checks if a .dockerignore file exists in the app directory and parses it
@@ -53,43 +57,26 @@ func separatePatterns(patterns []string) (excludes []string, includes []string)
 }
 
 type DockerignoreContext struct {
-	parsed   bool
-	excludes []string
-	includes []string
-	app      *app.App
-}
-
-func NewDockerignoreContext(app *app.App) *DockerignoreContext {
-	return &DockerignoreContext{
-		app: app,
-	}
-}
-
-// Parse parses the .dockerignore file and caches the results
-func (d *DockerignoreContext) Parse() ([]string, []string, error) {
-	if !d.parsed {
-		excludes, includes, err := CheckAndParseDockerignore(d.app)
-		if err != nil {
-			return nil, nil, err
-		}
-
-		d.excludes = excludes
-		d.includes = includes
-		d.parsed = true
-	}
-
-	return d.excludes, d.includes, nil
+	Excludes []string
+	Includes []string
+	HasFile  bool
 }
 
-func (d *DockerignoreContext) ParseWithLogging(logger interface{ LogInfo(string, ...interface{}) }) ([]string, []string, error) {
-	excludes, includes, err := d.Parse()
+func NewDockerignoreContext(app *app.App) (*DockerignoreContext, error) {
+	hasFile := app.HasFile(".dockerignore")
+	excludes, includes, err := CheckAndParseDockerignore(app)
 	if err != nil {
-		return nil, nil, err
+		return nil, err
 	}
-
-	if excludes != nil || includes != nil {
-		logger.LogInfo("Found .dockerignore file, applying filters")
+	if excludes != nil {
+		excludes = utils.RemoveDuplicates(excludes)
 	}
-
-	return excludes, includes, nil
+	if includes != nil {
+		includes = utils.RemoveDuplicates(includes)
+	}
+	return &DockerignoreContext{
+		Excludes: excludes,
+		Includes: includes,
+		HasFile:  hasFile,
+	}, nil
 }

core/plan/dockerignore_test.go

@@ -137,55 +137,26 @@ func TestDockerignoreContext(t *testing.T) {
 		testApp, err := app.NewApp(tempDir)
 		require.NoError(t, err)
 
-		ctx := NewDockerignoreContext(testApp)
-		require.NotNil(t, ctx)
-		require.Equal(t, testApp, ctx.app)
-		require.False(t, ctx.parsed)
-		require.Nil(t, ctx.excludes)
-		require.Nil(t, ctx.includes)
-	})
-
-	t.Run("parse caching", func(t *testing.T) {
-		examplePath := filepath.Join("..", "..", "examples", "dockerignore")
-		testApp, err := app.NewApp(examplePath)
+		ctx, err := NewDockerignoreContext(testApp)
 		require.NoError(t, err)
-
-		ctx := NewDockerignoreContext(testApp)
-
-		// First parse
-		excludes1, includes1, err1 := ctx.Parse()
-		require.NoError(t, err1)
-		require.True(t, ctx.parsed)
-
-		// Second parse should return cached results
-		excludes2, includes2, err2 := ctx.Parse()
-		require.NoError(t, err2)
-		require.Equal(t, excludes1, excludes2)
-		require.Equal(t, includes1, includes2)
+		require.NotNil(t, ctx)
+		require.False(t, ctx.HasFile)
+		require.Nil(t, ctx.Excludes)
+		require.Nil(t, ctx.Includes)
 	})
 
-	t.Run("parse with logging", func(t *testing.T) {
+	t.Run("context with dockerignore file", func(t *testing.T) {
 		examplePath := filepath.Join("..", "..", "examples", "dockerignore")
 		testApp, err := app.NewApp(examplePath)
 		require.NoError(t, err)
 
-		ctx := NewDockerignoreContext(testApp)
-
-		// Mock logger that captures calls
-		logCalls := []string{}
-		mockLogger := &mockLogger{logFunc: func(format string, args ...interface{}) {
-			logCalls = append(logCalls, format)
-		}}
-
-		excludes, includes, err := ctx.ParseWithLogging(mockLogger)
+		ctx, err := NewDockerignoreContext(testApp)
 		require.NoError(t, err)
-		require.NotNil(t, excludes)
-		require.NotNil(t, includes)
-		require.Contains(t, includes, "negation_test/should_exist.txt")
-		require.Contains(t, includes, "negation_test/existing_folder")
-
-		// Should have logged that dockerignore was found
-		require.Contains(t, logCalls, "Found .dockerignore file, applying filters")
+		require.True(t, ctx.HasFile)
+		require.NotNil(t, ctx.Excludes)
+		require.NotNil(t, ctx.Includes)
+		require.Contains(t, ctx.Includes, "negation_test/should_exist.txt")
+		require.Contains(t, ctx.Includes, "negation_test/existing_folder")
 	})
 
 	t.Run("parse nonexistent file", func(t *testing.T) {
@@ -196,13 +167,11 @@ func TestDockerignoreContext(t *testing.T) {
 		testApp, err := app.NewApp(tempDir)
 		require.NoError(t, err)
 
-		ctx := NewDockerignoreContext(testApp)
-
-		excludes, includes, err := ctx.Parse()
+		ctx, err := NewDockerignoreContext(testApp)
 		require.NoError(t, err)
-		require.Nil(t, excludes)
-		require.Nil(t, includes)
-		require.True(t, ctx.parsed) // Should still mark as parsed
+		require.False(t, ctx.HasFile)
+		require.Nil(t, ctx.Excludes)
+		require.Nil(t, ctx.Includes)
 	})
 
 	t.Run("parse error handling", func(t *testing.T) {
@@ -223,25 +192,62 @@ func TestDockerignoreContext(t *testing.T) {
 		testApp, err := app.NewApp(tempDir)
 		require.NoError(t, err)
 
-		ctx := NewDockerignoreContext(testApp)
-		excludes, includes, err := ctx.Parse()
-
+		ctx, err := NewDockerignoreContext(testApp)
 		require.Error(t, err)
-		require.Nil(t, excludes)
-		require.Nil(t, includes)
-		require.False(t, ctx.parsed) // Should not mark as parsed on error
+		require.Nil(t, ctx)
 	})
 }
 
-// Mock logger for testing
-type mockLogger struct {
-	logFunc func(string, ...interface{})
-}
+func TestDockerignoreDuplicatePatterns(t *testing.T) {
+	t.Run("duplicate patterns removed", func(t *testing.T) {
+		tempDir, err := os.MkdirTemp("", "dockerignore-test")
+		require.NoError(t, err)
+		defer os.RemoveAll(tempDir)
+
+		// Create test files
+		err = os.WriteFile(filepath.Join(tempDir, "keep.txt"), []byte("exists"), 0644)
+		require.NoError(t, err)
+
+		// Create .dockerignore with duplicate patterns
+		dockerignoreContent := `*.log
+*.log
+node_modules
+!keep.txt
+!keep.txt
+`
+		err = os.WriteFile(filepath.Join(tempDir, ".dockerignore"), []byte(dockerignoreContent), 0644)
+		require.NoError(t, err)
 
-func (m *mockLogger) LogInfo(format string, args ...interface{}) {
-	if m.logFunc != nil {
-		m.logFunc(format, args...)
-	}
+		testApp, err := app.NewApp(tempDir)
+		require.NoError(t, err)
+
+		ctx, err := NewDockerignoreContext(testApp)
+		require.NoError(t, err)
+
+		// Count occurrences of each pattern
+		logCount := 0
+		nodeModulesCount := 0
+		for _, pattern := range ctx.Excludes {
+			if pattern == "*.log" {
+				logCount++
+			}
+			if pattern == "node_modules" {
+				nodeModulesCount++
+			}
+		}
+
+		keepCount := 0
+		for _, pattern := range ctx.Includes {
+			if pattern == "keep.txt" {
+				keepCount++
+			}
+		}
+
+		// Verify no duplicates exist
+		require.LessOrEqual(t, logCount, 1, "*.log pattern should appear at most once")
+		require.LessOrEqual(t, nodeModulesCount, 1, "node_modules pattern should appear at most once")
+		require.LessOrEqual(t, keepCount, 1, "keep.txt pattern should appear at most once")
+	})
 }
 
 func TestCheckAndParseDockerignoreWithNegation(t *testing.T) {
@@ -259,7 +265,7 @@ func TestCheckAndParseDockerignoreWithNegation(t *testing.T) {
 		require.NoError(t, err)
 
 		// Create .dockerignore with mixed negation cases
-	dockerignoreContent := `
+		dockerignoreContent := `
 negation_test/*
 !negation_test/should_exist.txt
 !negation_test/should_not_exist.txt

docs/src/content/docs/guides/running-railpack-in-production.mdx

@@ -3,8 +3,9 @@ title: Running Railpack in Production
 description: Learn how to run Railpack in production as a platform
 ---
 
-This guide will walk you through running Railpack in production as a platform
-(like Railway).
+This guide walks through running Railpack in production as a platform
+(like Railway). This guide is not intended for end users using Railpack to
+containerize their applications.
 
 ## CLI vs Frontend