feat: Add configuration for Java buildpack

The detect now checks for func.yaml OR they explicitly defined an environment variable for the function name or package scan path. Signed-off-by: Andrew Su <[email protected]>
vmware-tanzu · May 31, 2022 · 8b7067d · 8b7067d
1 parent 0fccc84
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diff --git a/buildpacks/java/README.md b/buildpacks/java/README.md
@@ -4,18 +4,28 @@ The Java Function Buildpack is a Cloud Native Buildpack that provides a Spring B
 
 ## Behaviour
 This buildpack will participate if any of the following conditions are met:
-* A file with the name `func.yaml` is detected
+* One of the configuration environment variables are explicitly set.
+* A file with the name `func.yaml` is detected.
 
 The buildpack will do the following if detection passed:
 * Request for a JRE to be installed
 * Contributes the Spring Boot application to a layer marked `launch` with the layer's path prepended to `$CLASSPATH`
 * Contributes environment variables defined in `func.yaml` to the `launch` layer
+* Contributes environment variables to configure Spring Boot if any configuration variables are defined. (Overrides anything from `func.yaml`)
+
+## Configuration
+
+| Environment Variable | Description |
+|----------------------|-------------|
+| `$BP_FUNCTION` | Configure the composition of functions. Defaults to empty (load all functions). |
+| `$BP_FUNCTION_PACKAGES`    | Configure the package to search for functions.  Defaults to `functions`. |
+
 
 ## Getting started
 To get started you'll need to create a directory where your function will be defined.
 
 From within this directory we require a few files to properly detect this as a Java function:
-* `func.yaml`: We use this to configure the runtime environment variables. See the [Knative Func CLI docs](https://github.com/knative-sandbox/kn-plugin-func/blob/main/docs/guides/func_yaml.md) for more details.
+* `func.yaml` (optional): We use this to configure the runtime environment variables. See the [Knative Func CLI docs](https://github.com/knative-sandbox/kn-plugin-func/blob/main/docs/guides/func_yaml.md) for more details.
 * `pom.xml` or `build.gradle`: These are used by the other Java buildpacks to compile your function.
 * Java package in folder `src/main/java/functions`: This is the default location your function will be detected. If you do choose to use another package to store your functions, you will need to [set a new search location](#TODO).
 

diff --git a/buildpacks/java/buildpack.toml b/buildpacks/java/buildpack.toml
@@ -13,6 +13,18 @@ api = "0.6"
   include-files = ["README.md", "bin/build", "bin/detect", "bin/main", "buildpack.toml", "VERSION"]
   pre-package = "./build.sh"
 
+  [[metadata.configurations]]
+    build = true
+    default = ""
+    description = "The function to run"
+    name = "BP_FUNCTION"
+
+  [[metadata.configurations]]
+    build = true
+    default = "functions"
+    description = "The packages to scan for functions, the default is 'functions'"
+    name = "BP_FUNCTION_PACKAGES"
+
   [[metadata.dependencies]]
     id      = "invoker"
     name    = "Java Invoker"

diff --git a/buildpacks/java/java/build.go b/buildpacks/java/java/build.go
@@ -22,7 +22,7 @@ func (b Build) Build(context libcnb.BuildContext) (libcnb.BuildResult, error) {
 	b.Logger.Title(context.Buildpack)
 	result := libcnb.NewBuildResult()
 
-	_, err := libpak.NewConfigurationResolver(context.Buildpack, &b.Logger)
+	cr, err := libpak.NewConfigurationResolver(context.Buildpack, &b.Logger)
 	if err != nil {
 		return libcnb.BuildResult{}, fmt.Errorf("unable to create configuration resolver\n%w", err)
 	}
@@ -47,6 +47,11 @@ func (b Build) Build(context libcnb.BuildContext) (libcnb.BuildResult, error) {
 	if !ok {
 		return result, nil
 	}
+	if e.Metadata["has_func_yaml"] == true {
+		envs := NewFuncYamlEnvs(context.Application.Path)
+		envs.Logger = b.Logger
+		result.Layers = append(result.Layers, envs)
+	}
 
 	dep, err := dr.Resolve("invoker", "")
 	if err != nil {
@@ -71,10 +76,10 @@ func (b Build) Build(context libcnb.BuildContext) (libcnb.BuildResult, error) {
 		result.BOM.Entries = append(result.BOM.Entries, be)
 	}
 
-	f := NewFunction(e, context.Application.Path)
-	if err != nil {
-		return libcnb.BuildResult{}, fmt.Errorf("unable to create function\n%w", err)
-	}
+	funcDef, _ := cr.Resolve("BP_FUNCTION")
+	funcPackages, _ := cr.Resolve("BP_FUNCTION_PACKAGES")
+
+	f := NewFunction(funcPackages, funcDef, context.Application.Path)
 	f.Logger = b.Logger
 	result.Layers = append(result.Layers, f)
 

diff --git a/buildpacks/java/java/detect.go b/buildpacks/java/java/detect.go
@@ -9,6 +9,7 @@ import (
 	"path/filepath"
 
 	"github.com/buildpacks/libcnb"
+	"github.com/paketo-buildpacks/libpak"
 	"github.com/paketo-buildpacks/libpak/bard"
 	knfn "knative.dev/kn-plugin-func"
 )
@@ -17,22 +18,45 @@ type Detect struct {
 	Logger bard.Logger
 }
 
-func (d Detect) Detect(context libcnb.DetectContext) (libcnb.DetectResult, error) {
-	result := libcnb.DetectResult{}
+func (d Detect) checkConfigs(cr libpak.ConfigurationResolver) bool {
+	if _, defined := cr.Resolve("BP_FUNCTION"); defined {
+		return true
+	}
+
+	if _, defined := cr.Resolve("BP_FUNCTION_PACKAGES"); defined {
+		return true
+	}
+
+	return false
+}
 
-	configFile := filepath.Join(context.Application.Path, knfn.ConfigFile)
+func (d Detect) checkFuncYaml(appPath string) bool {
+	configFile := filepath.Join(appPath, knfn.ConfigFile)
 	_, err := os.Stat(configFile)
 	if err != nil {
-		d.logf(fmt.Sprintf("unable to find file '%s'", configFile))
-		return result, nil
+		d.Logger.Bodyf("unable to find file '%s'", configFile)
+		return false
 	}
 
-	f, err := knfn.NewFunction(context.Application.Path)
+	return true
+}
+
+func (d Detect) Detect(context libcnb.DetectContext) (libcnb.DetectResult, error) {
+	result := libcnb.DetectResult{}
+
+	appPath := context.Application.Path
+	funcYamlPass := d.checkFuncYaml(appPath)
+
+	cr, err := libpak.NewConfigurationResolver(context.Buildpack, &d.Logger)
 	if err != nil {
-		return result, fmt.Errorf("parsing function config: %v", err)
+		return result, fmt.Errorf("unable to create configuration resolver: %v", err)
 	}
 
-	envs := envsToMap(f.Envs)
+	configPass := d.checkConfigs(cr)
+	if err != nil {
+		d.Logger.Bodyf("unable to check buildpack configurations: %v", err)
+		return result, nil
+	}
 
 	result.Plans = append(result.Plans, libcnb.BuildPlan{
 		Provides: []libcnb.BuildPlanProvide{
@@ -44,8 +68,8 @@ func (d Detect) Detect(context libcnb.DetectContext) (libcnb.DetectResult, error
 			{
 				Name: "java-function",
 				Metadata: map[string]interface{}{
-					"launch": true,
-					"envs":   envs,
+					"launch":        true,
+					"has_func_yaml": funcYamlPass,
 				},
 			},
 			{
@@ -60,25 +84,6 @@ func (d Detect) Detect(context libcnb.DetectContext) (libcnb.DetectResult, error
 		},
 	})
 
-	result.Pass = true
+	result.Pass = funcYamlPass || configPass
 	return result, nil
 }
-
-func (d Detect) logf(format string, args ...interface{}) {
-	d.Logger.Infof(format, args...)
-}
-
-func envsToMap(envs knfn.Envs) map[string]string {
-	result := map[string]string{}
-
-	for _, e := range envs {
-		key := *e.Name
-		val := ""
-		if e.Value != nil {
-			val = *e.Value
-		}
-		result[key] = val
-	}
-
-	return result
-}
diff --git a/buildpacks/java/java/func_yaml_envs.go b/buildpacks/java/java/func_yaml_envs.go
@@ -0,0 +1,81 @@
+// Copyright 2021-2022 VMware, Inc.
+// SPDX-License-Identifier: BSD-2-Clause
+
+package java
+
+import (
+	"os"
+	"path/filepath"
+
+	"github.com/buildpacks/libcnb"
+	"github.com/paketo-buildpacks/libpak"
+	"github.com/paketo-buildpacks/libpak/bard"
+	knfn "knative.dev/kn-plugin-func"
+)
+
+type FuncYamlEnvs struct {
+	LayerContributor libpak.LayerContributor
+	Logger           bard.Logger
+
+	Envs map[string]string
+}
+
+func NewFuncYamlEnvs(applicationPath string) FuncYamlEnvs {
+	envs := getFuncYamlEnvs(applicationPath)
+	return FuncYamlEnvs{
+		LayerContributor: libpak.NewLayerContributor(
+			"func-yaml-envs",
+			envs,
+			libcnb.LayerTypes{
+				Launch: true,
+			},
+		),
+		Envs: envs,
+	}
+}
+
+func (f FuncYamlEnvs) Contribute(layer libcnb.Layer) (libcnb.Layer, error) {
+	f.LayerContributor.Logger = f.Logger
+	return f.LayerContributor.Contribute(layer, func() (libcnb.Layer, error) {
+		for k, v := range f.Envs {
+			layer.LaunchEnvironment.Default(k, v)
+		}
+		return layer, nil
+	})
+}
+
+func (f FuncYamlEnvs) Name() string {
+	return f.LayerContributor.Name
+}
+
+func getFuncYamlEnvs(applicationPath string) map[string]string {
+	envs := map[string]string{}
+
+	configFile := filepath.Join(applicationPath, knfn.ConfigFile)
+	_, err := os.Stat(configFile)
+	if err != nil {
+		return envs
+	}
+
+	f, err := knfn.NewFunction(applicationPath)
+	if err != nil {
+		return envs
+	}
+
+	return envsToMap(f.Envs)
+}
+
+func envsToMap(envs knfn.Envs) map[string]string {
+	result := map[string]string{}
+
+	for _, e := range envs {
+		key := *e.Name
+		val := ""
+		if e.Value != nil {
+			val = *e.Value
+		}
+		result[key] = val
+	}
+
+	return result
+}
diff --git a/buildpacks/java/java/function.go b/buildpacks/java/java/function.go
@@ -4,8 +4,6 @@
 package java
 
 import (
-	"strings"
-
 	"github.com/buildpacks/libcnb"
 	"github.com/paketo-buildpacks/libpak"
 	"github.com/paketo-buildpacks/libpak/bard"
@@ -15,45 +13,48 @@ type Function struct {
 	LayerContributor libpak.LayerContributor
 	Logger           bard.Logger
 
-	ApplicationPath string
-	Handler         string
-	Envs            map[string]interface{}
+	ApplicationPath    string
+	FunctionDefinition string
+	FunctionPackages   string
 }
 
-func NewFunction(plan libcnb.BuildpackPlanEntry, applicationPath string) Function {
-	envs := plan.Metadata["envs"].(map[string]interface{})
-
+func NewFunction(packages string, definition string, applicationPath string) Function {
 	return Function{
 		ApplicationPath: applicationPath,
 		LayerContributor: libpak.NewLayerContributor(
-			plan.Name,
-			envs,
+			"java-function",
+			map[string]string{
+				"packages":   packages,
+				"definition": definition,
+			},
 			libcnb.LayerTypes{
 				Launch: true,
 			},
 		),
-		Envs: envs,
+		FunctionPackages:   packages,
+		FunctionDefinition: definition,
 	}
 }
 
 func (f Function) Contribute(layer libcnb.Layer) (libcnb.Layer, error) {
 	f.LayerContributor.Logger = f.Logger
 
 	return f.LayerContributor.Contribute(layer, func() (libcnb.Layer, error) {
-		if len(f.Handler) > 0 {
-			if strings.ContainsAny(f.Handler, ".") {
-				layer.LaunchEnvironment.Default("SPRING_CLOUD_FUNCTION_FUNCTION_CLASS", f.Handler)
-			} else {
-				layer.LaunchEnvironment.Default("SPRING_CLOUD_FUNCTION_DEFINITION", f.Handler)
-			}
+		if len(f.FunctionPackages) > 0 {
+			layer.LaunchEnvironment.Default("SPRING_CLOUD_FUNCTION_SCAN_PACKAGES", f.FunctionPackages)
 		}
 
-		layer.LaunchEnvironment.Default("SPRING_CLOUD_FUNCTION_LOCATION", f.ApplicationPath)
-
-		for k, v := range f.Envs {
-			layer.LaunchEnvironment.Default(k, v)
+		if len(f.FunctionDefinition) > 0 {
+			// if strings.ContainsAny(f.Handler, ".") {
+			// 	layer.LaunchEnvironment.Default("SPRING_CLOUD_FUNCTION_FUNCTION_CLASS", f.Handler)
+			// } else {
+			// 	layer.LaunchEnvironment.Default("SPRING_CLOUD_FUNCTION_DEFINITION", f.FunctionDefinition)
+			// }
+			layer.LaunchEnvironment.Default("SPRING_CLOUD_FUNCTION_DEFINITION", f.FunctionDefinition)
 		}
 
+		layer.LaunchEnvironment.Default("SPRING_CLOUD_FUNCTION_LOCATION", f.ApplicationPath)
+
 		return layer, nil
 	})
 }