Command Plugin for generating the source code

Package.swift

@@ -38,6 +38,7 @@ let package = Package(
     products: [
         .executable(name: "swift-openapi-generator", targets: ["swift-openapi-generator"]),
         .plugin(name: "OpenAPIGenerator", targets: ["OpenAPIGenerator"]),
+        .plugin(name: "OpenAPIGeneratorCommand", targets: ["OpenAPIGeneratorCommand"]),
         .library(name: "_OpenAPIGeneratorCore", targets: ["_OpenAPIGeneratorCore"]),
     ],
     dependencies: [
@@ -151,5 +152,24 @@ let package = Package(
                 "swift-openapi-generator"
             ]
         ),
+
+        // Command Plugin
+        .plugin(
+            name: "OpenAPIGeneratorCommand",
+            capability: .command(
+                intent: .custom(
+                    verb: "generate-code-from-openapi",
+                    description: "Generate Swift code from an OpenAPI document."
+                ),
+                permissions: [
+                    .writeToPackageDirectory(
+                        reason: "To write the generated Swift files back into the source directory of the package."
+                    )
+                ]
+            ),
+            dependencies: [
+                "swift-openapi-generator"
+            ]
+        ),
     ]
 )

Plugins/OpenAPIGenerator/PluginsShared

@@ -0,0 +1 @@
+../../Plugins/PluginsShared

Plugins/OpenAPIGenerator/plugin.swift

@@ -16,81 +16,30 @@ import Foundation
 
 @main
 struct SwiftOpenAPIGeneratorPlugin {
-    enum Error: Swift.Error, CustomStringConvertible, LocalizedError {
-        case incompatibleTarget(targetName: String)
-        case noConfigFound(targetName: String)
-        case noDocumentFound(targetName: String)
-        case multiConfigFound(targetName: String, files: [Path])
-        case multiDocumentFound(targetName: String, files: [Path])
-
-        var description: String {
-            switch self {
-            case .incompatibleTarget(let targetName):
-                return
-                    "Incompatible target called '\(targetName)'. Only Swift source targets can be used with the Swift OpenAPI generator plugin."
-            case .noConfigFound(let targetName):
-                return
-                    "No config file found in the target named '\(targetName)'. Add a file called 'openapi-generator-config.yaml' or 'openapi-generator-config.yml' to the target's source directory. See documentation for details."
-            case .noDocumentFound(let targetName):
-                return
-                    "No OpenAPI document found in the target named '\(targetName)'. Add a file called 'openapi.yaml', 'openapi.yml' or 'openapi.json' (can also be a symlink) to the target's source directory. See documentation for details."
-            case .multiConfigFound(let targetName, let files):
-                return
-                    "Multiple config files found in the target named '\(targetName)', but exactly one is required. Found \(files.map(\.description).joined(separator: " "))."
-            case .multiDocumentFound(let targetName, let files):
-                return
-                    "Multiple OpenAPI documents found in the target named '\(targetName)', but exactly one is required. Found \(files.map(\.description).joined(separator: " "))."
-            }
-        }
-
-        var errorDescription: String? {
-            description
-        }
-    }
-
-    private var supportedConfigFiles: Set<String> { Set(["yaml", "yml"].map { "openapi-generator-config." + $0 }) }
-    private var supportedDocFiles: Set<String> { Set(["yaml", "yml", "json"].map { "openapi." + $0 }) }
-
     func createBuildCommands(
-        pluginWorkDirectory: PackagePlugin.Path,
-        tool: (String) throws -> PackagePlugin.PluginContext.Tool,
+        pluginWorkDirectory: Path,
+        tool: (String) throws -> PluginContext.Tool,
         sourceFiles: FileList,
         targetName: String
     ) throws -> [Command] {
-        let inputFiles = sourceFiles
-        let matchedConfigs = inputFiles.filter { supportedConfigFiles.contains($0.path.lastComponent) }.map(\.path)
-        guard matchedConfigs.count > 0 else {
-            throw Error.noConfigFound(targetName: targetName)
-        }
-        guard matchedConfigs.count == 1 else {
-            throw Error.multiConfigFound(targetName: targetName, files: matchedConfigs)
-        }
-        let config = matchedConfigs[0]
+        let inputs = try PluginUtils.validateInputs(
+            workingDirectory: pluginWorkDirectory,
+            tool: tool,
+            sourceFiles: sourceFiles,
+            targetName: targetName,
+            pluginSource: .build
+        )
 
-        let matchedDocs = inputFiles.filter { supportedDocFiles.contains($0.path.lastComponent) }.map(\.path)
-        guard matchedDocs.count > 0 else {
-            throw Error.noDocumentFound(targetName: targetName)
-        }
-        guard matchedDocs.count == 1 else {
-            throw Error.multiDocumentFound(targetName: targetName, files: matchedDocs)
-        }
-        let doc = matchedDocs[0]
-        let genSourcesDir = pluginWorkDirectory.appending("GeneratedSources")
-        let outputFiles: [Path] = GeneratorMode.allCases.map { genSourcesDir.appending($0.outputFileName) }
+        let outputFiles: [Path] = GeneratorMode.allCases.map { inputs.genSourcesDir.appending($0.outputFileName) }
         return [
             .buildCommand(
                 displayName: "Running swift-openapi-generator",
-                executable: try tool("swift-openapi-generator").path,
-                arguments: [
-                    "generate", "\(doc)",
-                    "--config", "\(config)",
-                    "--output-directory", "\(genSourcesDir)",
-                    "--is-plugin-invocation",
-                ],
+                executable: inputs.tool.path,
+                arguments: inputs.arguments,
                 environment: [:],
                 inputFiles: [
-                    config,
-                    doc,
+                    inputs.config,
+                    inputs.doc,
                 ],
                 outputFiles: outputFiles
             )
@@ -104,7 +53,7 @@ extension SwiftOpenAPIGeneratorPlugin: BuildToolPlugin {
         target: Target
     ) async throws -> [Command] {
         guard let swiftTarget = target as? SwiftSourceModuleTarget else {
-            throw Error.incompatibleTarget(targetName: target.name)
+            throw PluginError.incompatibleTarget(name: target.name)
         }
         return try createBuildCommands(
             pluginWorkDirectory: context.pluginWorkDirectory,

Plugins/OpenAPIGeneratorCommand/PluginsShared

@@ -0,0 +1 @@
+../../Plugins/PluginsShared

Plugins/OpenAPIGeneratorCommand/plugin.swift

@@ -0,0 +1,105 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the SwiftOpenAPIGenerator open source project
+//
+// Copyright (c) 2023 Apple Inc. and the SwiftOpenAPIGenerator project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.txt for the list of SwiftOpenAPIGenerator project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+import PackagePlugin
+import Foundation
+
+@main
+struct SwiftOpenAPIGeneratorPlugin {
+    func runCommand(
+        targetWorkingDirectory: Path,
+        tool: (String) throws -> PluginContext.Tool,
+        sourceFiles: FileList,
+        targetName: String
+    ) throws {
+        let inputs = try PluginUtils.validateInputs(
+            workingDirectory: targetWorkingDirectory,
+            tool: tool,
+            sourceFiles: sourceFiles,
+            targetName: targetName,
+            pluginSource: .command
+        )
+
+        let toolUrl = URL(fileURLWithPath: inputs.tool.path.string)
+        let process = Process()
+        process.executableURL = toolUrl
+        process.arguments = inputs.arguments
+        process.environment = [:]
+        try process.run()
+        process.waitUntilExit()
+        guard process.terminationStatus == 0 else {
+            throw PluginError.generatorFailure(targetName: targetName)
+        }
+    }
+}
+
+extension SwiftOpenAPIGeneratorPlugin: CommandPlugin {
+    func performCommand(
+        context: PluginContext,
+        arguments: [String]
+    ) async throws {
+        let targetNameArguments = arguments.filter({ $0 != "--target" })
+        let targets: [Target]
+        if targetNameArguments.isEmpty {
+            targets = context.package.targets
+        } else {
+            let matchingTargets = try context.package.targets(named: targetNameArguments)
+            let packageTargets = Set(context.package.targets.map(\.id))
+            let withLocalDependencies = matchingTargets.flatMap { [$0] + $0.recursiveTargetDependencies }
+                .filter { packageTargets.contains($0.id) }
+            let enumeratedKeyValues = withLocalDependencies.map(\.id).enumerated()
+                .map { (key: $0.element, value: $0.offset) }
+            let indexLookupTable = Dictionary(enumeratedKeyValues, uniquingKeysWith: { l, _ in l })
+            let groupedByID = Dictionary(grouping: withLocalDependencies, by: \.id)
+            let sortedUniqueTargets = groupedByID.map(\.value[0])
+                .sorted { indexLookupTable[$0.id, default: 0] < indexLookupTable[$1.id, default: 0] }
+            targets = sortedUniqueTargets
+        }
+
+        guard !targets.isEmpty else {
+            throw PluginError.noTargetsMatchingTargetNames(targetNameArguments)
+        }
+
+        var hadASuccessfulRun = false
+
+        for target in targets {
+            print("Considering target '\(target.name)':")
+            guard let swiftTarget = target as? SwiftSourceModuleTarget else {
+                print("- Not a swift source module. Can't generate OpenAPI code.")
+                continue
+            }
+            do {
+                print("- Trying OpenAPI code generation.")
+                try runCommand(
+                    targetWorkingDirectory: target.directory,
+                    tool: context.tool,
+                    sourceFiles: swiftTarget.sourceFiles,
+                    targetName: target.name
+                )
+                print("- ✅ OpenAPI code generation for target '\(target.name)' successfully completed.")
+                hadASuccessfulRun = true
+            } catch let error as PluginError {
+                if error.isMisconfigurationError {
+                    print("- OpenAPI code generation failed with error.")
+                    throw error
+                } else {
+                    print("- Stopping because target isn't configured for OpenAPI code generation.")
+                }
+            }
+        }
+
+        guard hadASuccessfulRun else {
+            throw PluginError.noTargetsWithExpectedFiles(targetNames: targets.map(\.name))
+        }
+    }
+}

Plugins/PluginsShared/PluginError.swift

@@ -0,0 +1,145 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the SwiftOpenAPIGenerator open source project
+//
+// Copyright (c) 2023 Apple Inc. and the SwiftOpenAPIGenerator project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.txt for the list of SwiftOpenAPIGenerator project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+import PackagePlugin
+import Foundation
+
+enum PluginError: Swift.Error, CustomStringConvertible, LocalizedError {
+    case incompatibleTarget(name: String)
+    case generatorFailure(targetName: String)
+    case noTargetsWithExpectedFiles(targetNames: [String])
+    case noTargetsMatchingTargetNames([String])
+    case fileErrors([FileError])
+
+    var description: String {
+        switch self {
+        case .incompatibleTarget(let name):
+            return
+                "Incompatible target called '\(name)'. Only Swift source targets can be used with the Swift OpenAPI Generator plugin."
+        case .generatorFailure(let targetName):
+            return "The generator failed to generate OpenAPI files for target '\(targetName)'."
+        case .noTargetsWithExpectedFiles(let targetNames):
+            let fileNames = FileError.Kind.allCases.map(\.name)
+                .joined(separator: ", ", lastSeparator: " or ")
+            let targetNames = targetNames.joined(separator: ", ", lastSeparator: " and ")
+            return
+                "Targets with names \(targetNames) don't contain any \(fileNames) files with expected names. See documentation for details."
+        case .noTargetsMatchingTargetNames(let targetNames):
+            let targetNames = targetNames.joined(separator: ", ", lastSeparator: " and ")
+            return "Found no targets with names \(targetNames)."
+        case .fileErrors(let fileErrors):
+            return "Issues with required files: \(fileErrors.map(\.description).joined(separator: ", and"))."
+        }
+    }
+
+    var errorDescription: String? {
+        description
+    }
+
+    /// The error is definitely due to misconfiguration of a target.
+    var isMisconfigurationError: Bool {
+        switch self {
+        case .incompatibleTarget:
+            return false
+        case .generatorFailure:
+            return false
+        case .noTargetsWithExpectedFiles:
+            return false
+        case .noTargetsMatchingTargetNames:
+            return false
+        case .fileErrors(let errors):
+            return errors.isMisconfigurationError
+        }
+    }
+}
+
+struct FileError: Swift.Error, CustomStringConvertible, LocalizedError {
+
+    /// The kind of the file.
+    enum Kind: CaseIterable {
+        /// Config file.
+        case config
+        /// OpenAPI document file.
+        case document
+
+        var name: String {
+            switch self {
+            case .config:
+                return "config"
+            case .document:
+                return "OpenAPI document"
+            }
+        }
+    }
+
+    /// Encountered issue.
+    enum Issue {
+        /// File wasn't found.
+        case noFilesFound
+        /// More than 1 file found.
+        case multipleFilesFound(files: [Path])
+
+        /// The error is definitely due to misconfiguration of a target.
+        var isMisconfigurationError: Bool {
+            switch self {
+            case .noFilesFound:
+                return false
+            case .multipleFilesFound:
+                return true
+            }
+        }
+    }
+
+    let targetName: String
+    let fileKind: Kind
+    let issue: Issue
+
+    var description: String {
+        switch fileKind {
+        case .config:
+            switch issue {
+            case .noFilesFound:
+                return
+                    "No config file found in the target named '\(targetName)'. Add a file called 'openapi-generator-config.yaml' or 'openapi-generator-config.yml' to the target's source directory. See documentation for details."
+            case .multipleFilesFound(let files):
+                return
+                    "Multiple config files found in the target named '\(targetName)', but exactly one is expected. Found \(files.map(\.description).joined(separator: " "))."
+            }
+        case .document:
+            switch issue {
+            case .noFilesFound:
+                return
+                    "No OpenAPI document found in the target named '\(targetName)'. Add a file called 'openapi.yaml', 'openapi.yml' or 'openapi.json' (can also be a symlink) to the target's source directory. See documentation for details."
+            case .multipleFilesFound(let files):
+                return
+                    "Multiple OpenAPI documents found in the target named '\(targetName)', but exactly one is expected. Found \(files.map(\.description).joined(separator: " "))."
+            }
+        }
+    }
+
+    var errorDescription: String? {
+        description
+    }
+}
+
+private extension Array where Element == FileError {
+    /// The error is definitely due to misconfiguration of a target.
+    var isMisconfigurationError: Bool {
+        // If errors for both files exist and none is a "Misconfiguration Error" then the
+        // error can be related to a target that isn't supposed to be generator compatible at all.
+        if count == FileError.Kind.allCases.count, self.allSatisfy({ !$0.issue.isMisconfigurationError }) {
+            return false
+        }
+        return true
+    }
+}

Plugins/PluginsShared/PluginSource.swift

@@ -0,0 +1 @@
+../../Sources/swift-openapi-generator/PluginSource.swift