Introduce ENV simulation

Author: stevapple

.gitignore

@@ -9,4 +9,4 @@ xcuserdata
 Package.resolved
 .serverless
 docker
-.env
+.env

README.md

@@ -158,7 +158,7 @@ public protocol ByteBufferSCFHandler {
     /// The SCF handling method.
     /// Concrete SCF handlers implement this method to provide the SCF functionality.
     ///
-    /// - parameters:
+    /// - Parameters:
     ///     - context: Runtime `Context`.
     ///     - event: The event or input payload encoded as `ByteBuffer`.
     ///
@@ -191,7 +191,7 @@ public protocol EventLoopSCFHandler: ByteBufferSCFHandler {
     /// The SCF handling method.
     /// Concrete SCF handlers implement this method to provide the SCF functionality.
     ///
-    /// - parameters:
+    /// - Parameters:
     ///     - context: Runtime `Context`.
     ///     - event: Event of type `In` representing the event or request.
     ///
@@ -201,7 +201,8 @@ public protocol EventLoopSCFHandler: ByteBufferSCFHandler {
 
     /// Encode a response of type `Out` to `ByteBuffer`.
     /// Concrete SCF handlers implement this method to provide coding functionality.
-    /// - parameters:
+    ///
+    /// - Parameters:
     ///     - allocator: A `ByteBufferAllocator` to help allocate the `ByteBuffer`.
     ///     - value: Response of type `Out`.
     ///
@@ -211,7 +212,7 @@ public protocol EventLoopSCFHandler: ByteBufferSCFHandler {
     /// Decode a`ByteBuffer` to a request or event of type `In`
     /// Concrete SCF handlers implement this method to provide coding functionality.
     ///
-    /// - parameters:
+    /// - Parameters:
     ///     - buffer: The `ByteBuffer` to decode.
     ///
     /// - Returns: A request or event of type `In`.
@@ -235,7 +236,7 @@ public protocol SCFHandler: EventLoopSCFHandler {
     /// The SCF handling method.
     /// Concrete SCF handlers implement this method to provide the SCF functionality.
     ///
-    /// - parameters:
+    /// - Parameters:
     ///     - context: Runtime `Context`.
     ///     - event: Event of type `In` representing the event or request.
     ///     - callback: Completion handler to report the result of the SCF function back to the runtime engine.
@@ -298,13 +299,13 @@ public final class Context: CustomDebugStringConvertible {
 
     /// `Logger` to log with.
     ///
-    /// - note: The `LogLevel` can be configured using the `LOG_LEVEL` environment variable.
+    /// - Note: The `LogLevel` can be configured using the `LOG_LEVEL` environment variable.
     public let logger: Logger
 
     /// The `EventLoop` the SCF function is executed on. Use this to schedule work with.
     /// This is useful when implementing the `EventLoopSCFHandler` protocol.
     ///
-    /// - note: The `EventLoop` is shared with the SCF Runtime Engine and should be handled with extra care.
+    /// - Note: The `EventLoop` is shared with the SCF Runtime Engine and should be handled with extra care.
     ///         Most importantly the `EventLoop` must never be blocked.
     public let eventLoop: EventLoop
 

Sources/TencentSCFRuntime/SCF+Codable.swift

@@ -38,10 +38,10 @@ extension SCF {
 
     /// Run a cloud function defined by implementing the `CodableClosure` function.
     ///
-    /// - parameters:
+    /// - Parameters:
     ///     - closure: `CodableClosure` based SCF function.
     ///
-    /// - note: This is a blocking operation that will run forever, as its lifecycle is managed by the Tencent SCF Runtime Engine.
+    /// - Note: This is a blocking operation that will run forever, as its lifecycle is managed by the Tencent SCF Runtime Engine.
     public static func run<In: Decodable, Out: Encodable>(_ closure: @escaping CodableClosure<In, Out>) {
         self.run(CodableClosureWrapper(closure))
     }
@@ -51,10 +51,10 @@ extension SCF {
 
     /// Run a cloud function defined by implementing the `CodableVoidClosure` function.
     ///
-    /// - parameters:
+    /// - Parameters:
     ///     - closure: `CodableVoidClosure` based SCF function.
     ///
-    /// - note: This is a blocking operation that will run forever, as its lifecycle is managed by the Tencent SCF Runtime Engine.
+    /// - Note: This is a blocking operation that will run forever, as its lifecycle is managed by the Tencent SCF Runtime Engine.
     public static func run<In: Decodable>(_ closure: @escaping CodableVoidClosure<In>) {
         self.run(CodableVoidClosureWrapper(closure))
     }

Sources/TencentSCFRuntimeCore/SCF+Env.swift

@@ -0,0 +1,77 @@
+//===------------------------------------------------------------------------------------===//
+//
+// This source file is part of the SwiftTencentSCFRuntime open source project
+//
+// Copyright (c) 2020 stevapple and the SwiftTencentSCFRuntime project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.txt for the list of SwiftTencentSCFRuntime project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===------------------------------------------------------------------------------------===//
+
+#if os(Linux)
+import Glibc
+#else
+import Darwin.C
+#endif
+
+// MARK: Env
+
+extension SCF {
+    /// Environment variables helper for SCF.
+    public enum Env {
+        #if DEBUG
+        /// Preset overriding to simulate the SCF runtime context.
+        private static let preset = [
+            "TENCENTCLOUD_UIN": "100000000001",
+            "TENCENTCLOUD_APPID": "1250000000",
+            "TENCENTCLOUD_REGION": "ap-beijing",
+            "SCF_FUNCTIONNAME": "my-swift-function",
+            "SCF_NAMESPACE": "default",
+            "SCF_FUNCTIONVERSION": "$LATEST",
+        ]
+
+        /// Custom environment variables overriding.
+        private static var custom: [String: String] = [:]
+
+        /// Batch override environment variables with `Dictionary`.
+        public static func update(with dictionary: [String: String]) {
+            Self.custom.merge(dictionary) { $1 }
+        }
+
+        /// Utility to read/override environment variables.
+        public static subscript(_ key: String) -> String? {
+            get {
+                if let value = Self.custom[key] {
+                    return value
+                } else if let value = getenv(key) {
+                    return String(cString: value)
+                } else if let value = Self.preset[key] {
+                    return value
+                } else {
+                    return nil
+                }
+            }
+            set(newValue) {
+                Self.custom[key] = newValue
+            }
+        }
+
+        // for testing and internal use
+        internal static func reset() {
+            Self.custom = [:]
+        }
+        #else
+        /// Utility to read environment variables.
+        public static subscript(_ key: String) -> String? {
+            guard let value = getenv(key) else {
+                return nil
+            }
+            return String(cString: value)
+        }
+        #endif
+    }
+}

Sources/TencentSCFRuntimeCore/SCF+LocalServer.swift

@@ -44,11 +44,11 @@ import NIOHTTP1
 extension SCF {
     /// Execute code in the context of a mock SCF server.
     ///
-    /// - parameters:
+    /// - Parameters:
     ///     - invocationEndpoint: The endpoint to post events to.
     ///     - body: Code to run within the context of the mock server. Typically this would be a `SCF.run` function call.
     ///
-    /// - note: This API is designed stricly for local testing and is behind a DEBUG flag.
+    /// - Note: This API is designed stricly for local testing and is behind a DEBUG flag.
     @discardableResult
     static func withLocalServer<Value>(invocationEndpoint: String? = nil, _ body: @escaping () -> Value) throws -> Value {
         let server = LocalFunction.Server(invocationEndpoint: invocationEndpoint)

Sources/TencentSCFRuntimeCore/SCF+String.swift

@@ -34,10 +34,10 @@ extension SCF {
 
     /// Run a cloud function defined by implementing the `StringClosure` function.
     ///
-    /// - parameters:
+    /// - Parameters:
     ///     - closure: `StringClosure` based SCF function.
     ///
-    /// - note: This is a blocking operation that will run forever, as its lifecycle is managed by the Tencent SCF Runtime Engine.
+    /// - Note: This is a blocking operation that will run forever, as its lifecycle is managed by the Tencent SCF Runtime Engine.
     public static func run(_ closure: @escaping StringClosure) {
         self.run(closure: closure)
     }
@@ -47,10 +47,10 @@ extension SCF {
 
     /// Run a cloud function defined by implementing the `StringVoidClosure` function.
     ///
-    /// - parameters:
+    /// - Parameters:
     ///     - closure: `StringVoidClosure` based SCF function.
     ///
-    /// - note: This is a blocking operation that will run forever, as its lifecycle is managed by the Tencent SCF Runtime Engine.
+    /// - Note: This is a blocking operation that will run forever, as its lifecycle is managed by the Tencent SCF Runtime Engine.
     public static func run(_ closure: @escaping StringVoidClosure) {
         self.run(closure: closure)
     }

Sources/TencentSCFRuntimeCore/SCF.swift

@@ -25,12 +25,6 @@
 //
 //===------------------------------------------------------------------------------------===//
 
-#if os(Linux)
-import Glibc
-#else
-import Darwin.C
-#endif
-
 import Backtrace
 import Logging
 import NIO
@@ -44,10 +38,10 @@ public enum SCF {
 
     /// Run a cloud function defined by implementing the `SCFHandler` protocol.
     ///
-    /// - parameters:
+    /// - Parameters:
     ///     - handler: `ByteBufferSCFHandler` based SCF function.
     ///
-    /// - note: This is a blocking operation that will run forever, as its lifecycle is managed by the Tencent SCF Runtime Engine.
+    /// - Note: This is a blocking operation that will run forever, as its lifecycle is managed by the Tencent SCF Runtime Engine.
     public static func run(_ handler: Handler) {
         self.run(handler: handler)
     }
@@ -56,32 +50,24 @@ public enum SCF {
     /// Use this to initialize all your resources that you want to cache between invocations. This could be database connections and HTTP clients for example.
     /// It is encouraged to use the given `EventLoop`'s conformance to `EventLoopGroup` when initializing NIO dependencies. This will improve overall performance.
     ///
-    /// - parameters:
+    /// - Parameters:
     ///     - factory: A `ByteBufferSCFHandler` factory.
     ///
-    /// - note: This is a blocking operation that will run forever, as its lifecycle is managed by the Tencent SCF Runtime Engine.
+    /// - Note: This is a blocking operation that will run forever, as its lifecycle is managed by the Tencent SCF Runtime Engine.
     public static func run(_ factory: @escaping HandlerFactory) {
         self.run(factory: factory)
     }
 
     /// Run a cloud function defined by implementing the `SCFHandler` protocol provided via a factory, typically a constructor.
     ///
-    /// - parameters:
+    /// - Parameters:
     ///     - factory: A `ByteBufferSCFHandler` factory.
     ///
-    /// - note: This is a blocking operation that will run forever, as its lifecycle is managed by the Tencent SCF Runtime Engine.
+    /// - Note: This is a blocking operation that will run forever, as its lifecycle is managed by the Tencent SCF Runtime Engine.
     public static func run(_ factory: @escaping (InitializationContext) throws -> Handler) {
         self.run(factory: factory)
     }
 
-    /// Utility to access/read environment variables.
-    public static func env(_ name: String) -> String? {
-        guard let value = getenv(name) else {
-            return nil
-        }
-        return String(cString: value)
-    }
-
     // for testing and internal use
     @discardableResult
     internal static func run(configuration: Configuration = .init(), handler: Handler) -> Result<Int, Error> {
@@ -145,7 +131,7 @@ public enum SCF {
 
         // Start local server for debugging in DEBUG mode only.
         #if DEBUG
-        if SCF.env("LOCAL_SCF_SERVER_ENABLED").flatMap(Bool.init) ?? false {
+        if SCF.Env["LOCAL_SCF_SERVER_ENABLED"].flatMap(Bool.init) ?? false {
             do {
                 return try SCF.withLocalServer {
                     _run(configuration, factory)

Sources/TencentSCFRuntimeCore/SCFConfiguration.swift

@@ -49,7 +49,7 @@ extension SCF {
             let logLevel: Logger.Level
 
             init(logLevel: Logger.Level? = nil) {
-                self.logLevel = logLevel ?? env("LOG_LEVEL").flatMap(Logger.Level.init) ?? .info
+                self.logLevel = logLevel ?? Env["LOG_LEVEL"].flatMap(Logger.Level.init) ?? .info
             }
 
             var description: String {
@@ -64,8 +64,8 @@ extension SCF {
 
             init(id: String? = nil, maxTimes: Int? = nil, stopSignal: Signal? = nil) {
                 self.id = id ?? "\(DispatchTime.now().uptimeNanoseconds)"
-                self.maxTimes = maxTimes ?? env("MAX_REQUESTS").flatMap(Int.init) ?? 0
-                self.stopSignal = stopSignal ?? env("STOP_SIGNAL").flatMap(Int32.init).flatMap(Signal.init) ?? Signal.TERM
+                self.maxTimes = maxTimes ?? Env["MAX_REQUESTS"].flatMap(Int.init) ?? 0
+                self.stopSignal = stopSignal ?? Env["STOP_SIGNAL"].flatMap(Int32.init).flatMap(Signal.init) ?? Signal.TERM
                 precondition(self.maxTimes >= 0, "maxTimes must be equal or larger than 0")
             }
 
@@ -88,11 +88,11 @@ extension SCF {
                     self.ip = String(ipPort[0])
                     self.port = port
                 } else {
-                    self.ip = env("SCF_RUNTIME_API") ?? "127.0.0.1"
-                    self.port = env("SCF_RUNTIME_API_PORT").flatMap(Int.init) ?? 9001
+                    self.ip = Env["SCF_RUNTIME_API"] ?? "127.0.0.1"
+                    self.port = Env["SCF_RUNTIME_API_PORT"].flatMap(Int.init) ?? 9001
                 }
-                self.keepAlive = keepAlive ?? env("KEEP_ALIVE").flatMap(Bool.init) ?? true
-                self.requestTimeout = requestTimeout ?? env("REQUEST_TIMEOUT").flatMap(Int64.init).flatMap { .milliseconds($0) }
+                self.keepAlive = keepAlive ?? Env["KEEP_ALIVE"].flatMap(Bool.init) ?? true
+                self.requestTimeout = requestTimeout ?? Env["REQUEST_TIMEOUT"].flatMap(Int64.init).flatMap { .milliseconds($0) }
             }
 
             var description: String {