Support Projects loaded from arbitrary URIs

DEVELOPMENT.adoc

@@ -0,0 +1,43 @@
+:uri-pkl-repo: https://github.com/apple/pkl
+
+= Pkl Go Development Guide
+
+== Debugging the Pkl Server
+
+The pkl-go evaluator API runs `pkl server` as a subprocess, which presents obstacles for directly debugging the server process.
+It is possible to
+
+*Debug Stub Setup*
+
+. Create a file named `debugpkl`
+. Mark the file executable with `chmod +x debugpkl`
+. Populate the file with this content (note: the path to the executable will depend on where the Pkl repo is cloned):
+
+[,shell]
+----
+#!/bin/sh
+
+exec java -agentlib:jdwp=transport=dt_socket,server=n,address=localhost:5005,suspend=y -jar /path/to/pkl/pkl-cli/build/executable/jpkl "$@"
+----
+
+
+*IntelliJ IDEA Setup:*
+
+. Open the {uri-pkl-repo}[pkl] project
+. Build `jpkl` by running `./gradlew javaExecutable` so it is available to the script defined above
+. Run > Edit Configurations...
+. Add a new "Remote JVM Debug" configuration
+. Provide a name, eg. `debugpkl`
+. Under "Configuration", select the "Listen to remote JVM" debugger mode
+. Enable "Auto restart"
+. Ensure Host is "localhost" and Port is "5005"
+
+*Usage*
+
+. Configure pkl-go to use `debugpkl` as the server executable: `export PKL_EXEC=./debugpkl`
+. Optionally, turn on extra debug output: `export PKL_DEBUG=1`
+. Define breakpoints as desired in the Pkl codebase using IntelliJ
+. In IntelliJ, start debugging the "Remote JVM Debug" configuration defined above
+. Execute the process using pkl-go
+
+When the Pkl server execution reaches a defined breakpoint, it will pause and activate the debugger in IntelliJ.

pkl/evaluator_options.go

@@ -16,7 +16,6 @@
 package pkl
 
 import (
-	"fmt"
 	"io/fs"
 	"os"
 	"path"
@@ -56,10 +55,16 @@ type EvaluatorOptions struct {
 	//   - `"yaml"`
 	OutputFormat string
 
-	// AllowedModules is the URI patterns that determine which modules can be loaded and evaluated.
+	// AllowedModules defines URI patterns that determine which modules are permitted to be loaded and evaluated.
+	// Patterns are regular expressions in the dialect understood by [java.util.regex.Pattern].
+	//
+	// [java.util.regex.Pattern]: https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/util/regex/Pattern.html
 	AllowedModules []string
 
-	// AllowedResources is the URI patterns that determine which resources can be loaded and evaluated.
+	// AllowedResources defines URI patterns that determine which resources are permitted to be loaded and evaluated.
+	// Patterns are regular expressions in the dialect understood by [java.util.regex.Pattern].
+	//
+	// [java.util.regex.Pattern]: https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/util/regex/Pattern.html
 	AllowedResources []string
 
 	// ResourceReaders are the resource readers to be used by the evaluator.
@@ -78,7 +83,7 @@ type EvaluatorOptions struct {
 	// Attempting to read past the root directory is an error.
 	RootDir string
 
-	// ProjectDir is the project directory for the evaluator.
+	// ProjectFileURI is the project directory for the evaluator.
 	//
 	// Setting this determines how Pkl resolves dependency notation imports.
 	// It causes Pkl to look for the resolved dependencies relative to this directory,
@@ -97,13 +102,13 @@ type EvaluatorOptions struct {
 	//
 	// To emulate the CLI's `--project-dir` flag, create an evaluator with NewProjectEvaluator,
 	// or EvaluatorManager.NewProjectEvaluator.
-	ProjectDir string
+	ProjectBaseURI string
 
-	// DeclaredProjectDepenedencies is set of dependencies available to modules within ProjectDir.
+	// DeclaredProjectDepenedencies is set of dependencies available to modules within ProjectBaseURI.
 	//
-	// When importing dependencies, a PklProject.deps.json file must exist within ProjectDir
+	// When importing dependencies, a PklProject.deps.json file must exist within ProjectBaseURI
 	// that contains the project's resolved dependencies.
-	DeclaredProjectDepenedencies *ProjectDependencies
+	DeclaredProjectDependencies *ProjectDependencies
 }
 
 type ProjectRemoteDependency struct {
@@ -201,12 +206,12 @@ func (e *EvaluatorOptions) toMessage() *msgapi.CreateEvaluator {
 }
 
 func (e *EvaluatorOptions) project() *msgapi.ProjectOrDependency {
-	if e.ProjectDir == "" {
+	if e.ProjectBaseURI == "" {
 		return nil
 	}
 	return &msgapi.ProjectOrDependency{
-		ProjectFileUri: fmt.Sprintf("file://%s/PklProject", e.ProjectDir),
-		Dependencies:   e.DeclaredProjectDepenedencies.toMessage(),
+		ProjectFileUri: e.ProjectBaseURI + "/PklProject",
+		Dependencies:   e.DeclaredProjectDependencies.toMessage(),
 	}
 }
 
@@ -257,7 +262,7 @@ var WithDefaultCacheDir = func(opts *EvaluatorOptions) {
 var WithResourceReader = func(reader ResourceReader) func(opts *EvaluatorOptions) {
 	return func(opts *EvaluatorOptions) {
 		opts.ResourceReaders = append(opts.ResourceReaders, reader)
-		opts.AllowedResources = append(opts.AllowedResources, reader.Scheme())
+		opts.AllowedResources = append(opts.AllowedResources, reader.Scheme()+":")
 	}
 }
 
@@ -266,7 +271,7 @@ var WithResourceReader = func(reader ResourceReader) func(opts *EvaluatorOptions
 var WithModuleReader = func(reader ModuleReader) func(opts *EvaluatorOptions) {
 	return func(opts *EvaluatorOptions) {
 		opts.ModuleReaders = append(opts.ModuleReaders, reader)
-		opts.AllowedModules = append(opts.AllowedModules, reader.Scheme())
+		opts.AllowedModules = append(opts.AllowedModules, reader.Scheme()+":")
 	}
 }
 
@@ -320,8 +325,8 @@ var WithProjectEvaluatorSettings = func(project *Project) func(opts *EvaluatorOp
 // WithProjectDependencies configures the evaluator with dependencies from the specified project.
 var WithProjectDependencies = func(project *Project) func(opts *EvaluatorOptions) {
 	return func(opts *EvaluatorOptions) {
-		opts.ProjectDir = strings.TrimPrefix(strings.TrimSuffix(project.ProjectFileUri, "/PklProject"), "file://")
-		opts.DeclaredProjectDepenedencies = project.Dependencies()
+		opts.ProjectBaseURI = strings.TrimSuffix(project.ProjectFileUri, "/PklProject")
+		opts.DeclaredProjectDependencies = project.Dependencies()
 	}
 }
 

pkl/reader.go

@@ -22,6 +22,7 @@ import (
 // Reader is the base implementation shared by a ResourceReader and a ModuleReader.
 type Reader interface {
 	// Scheme returns the scheme part of the URL that this reader can read.
+	// The value should be the URI scheme up to (not including) ":"
 	Scheme() string
 
 	// IsGlobbable tells if this reader supports globbing via Pkl's `import*` and `glob*` keywords