add an env variable for host to be consistent

Author: sebsto

Sources/AWSLambdaRuntime/Lambda+LocalServer.swift

@@ -21,7 +21,7 @@ import NIOHTTP1
 import NIOPosix
 import Synchronization
 
-// This functionality is designed for local testing hence being a #if DEBUG flag.
+// This functionality is designed for local testing when the LocalServerSupport trait is enabled.
 
 // For example:
 // try Lambda.withLocalServer {
@@ -41,22 +41,25 @@ extension Lambda {
     /// Execute code in the context of a mock Lambda server.
     ///
     /// - parameters:
-    ///     - invocationEndpoint: The endpoint to post events to.
+    ///     - host: the hostname or IP address to listen on
     ///     - port: the TCP port to listen to
+    ///     - invocationEndpoint: The endpoint to post events to.
     ///     - body: Code to run within the context of the mock server. Typically this would be a Lambda.run function call.
     ///
-    /// - note: This API is designed strictly for local testing and is behind a DEBUG flag
+    /// - note: This API is designed strictly for local testing when the LocalServerSupport trait is enabled.
     @usableFromInline
     static func withLocalServer(
-        invocationEndpoint: String? = nil,
+        host: String,
         port: Int,
+        invocationEndpoint: String? = nil,
         logger: Logger,
         _ body: sending @escaping () async throws -> Void
     ) async throws {
         do {
             try await LambdaHTTPServer.withLocalServer(
-                invocationEndpoint: invocationEndpoint,
+                host: host,
                 port: port,
+                invocationEndpoint: invocationEndpoint,
                 logger: logger
             ) {
                 try await body()
@@ -113,9 +116,9 @@ internal struct LambdaHTTPServer {
     }
 
     static func withLocalServer<Result: Sendable>(
-        invocationEndpoint: String?,
-        host: String = "127.0.0.1",
+        host: String,
         port: Int,
+        invocationEndpoint: String?,
         eventLoopGroup: MultiThreadedEventLoopGroup = .singleton,
         logger: Logger,
         _ closure: sending @escaping () async throws -> Result

Sources/AWSLambdaRuntime/LambdaRuntime.swift

@@ -126,16 +126,19 @@ public final class LambdaRuntime<Handler>: Sendable where Handler: StreamingLamb
             // we're not running on Lambda and we're compiled in DEBUG mode,
             // let's start a local server for testing
 
+            let host = Lambda.env("LOCAL_LAMBDA_HOST") ?? "127.0.0.1"
             let port = Lambda.env("LOCAL_LAMBDA_PORT").flatMap(Int.init) ?? 7000
+            let endpoint = Lambda.env("LOCAL_LAMBDA_INVOCATION_ENDPOINT")
 
             try await Lambda.withLocalServer(
-                invocationEndpoint: Lambda.env("LOCAL_LAMBDA_SERVER_INVOCATION_ENDPOINT"),
+                host: host,
                 port: port,
+                invocationEndpoint: endpoint,
                 logger: self.logger
             ) {
 
                 try await LambdaRuntimeClient.withRuntimeClient(
-                    configuration: .init(ip: "127.0.0.1", port: port),
+                    configuration: .init(ip: host, port: port),
                     eventLoop: self.eventLoop,
                     logger: self.logger
                 ) { runtimeClient in
@@ -147,7 +150,7 @@ public final class LambdaRuntime<Handler>: Sendable where Handler: StreamingLamb
                 }
             }
             #else
-            // in release mode, we can't start a local server because the local server code is not compiled.
+            // When the LocalServerSupport trait is disabled, we can't start a local server because the local server code is not compiled.
             throw LambdaRuntimeError(code: .missingLambdaRuntimeAPIEnvironmentVariable)
             #endif
         }

readme.md

@@ -464,28 +464,22 @@ curl -v --header "Content-Type:\ application/json" --data @events/create-session
 * Connection #0 to host 127.0.0.1 left intact
 {"statusCode":200,"isBase64Encoded":false,"body":"...","headers":{"Access-Control-Allow-Origin":"*","Content-Type":"application\/json; charset=utf-8","Access-Control-Allow-Headers":"*"}}
 ```
-### Modifying the local endpoint
+### Modifying the local server URI
 
-By default, when using the local Lambda server, it listens on the `/invoke` endpoint.
+By default, when using the local Lambda server during your tests, it listens on `http://127.0.0.1:7000/invoke`.
 
-Some testing tools, such as the [AWS Lambda runtime interface emulator](https://docs.aws.amazon.com/lambda/latest/dg/images-test.html), require a different endpoint. In that case, you can use the `LOCAL_LAMBDA_SERVER_INVOCATION_ENDPOINT` environment variable to force the runtime to listen on a different endpoint.
+Some testing tools, such as the [AWS Lambda runtime interface emulator](https://docs.aws.amazon.com/lambda/latest/dg/images-test.html), require a different endpoint, the port might be used, or you may want to bind a specific IP address.
 
-Example:
-
-```sh
-LOCAL_LAMBDA_SERVER_INVOCATION_ENDPOINT=/2015-03-31/functions/function/invocations swift run
-```
-
-## Modifying the local port 
-
-By default, when using the local Lambda server, it listens on TCP port 7000.
+In these cases, you can use three environment variables to control the local server:
 
-On macOS, this port might be used by AirPlay under some configurations. You can use the `LOCAL_LAMBDA_PORT` environment variable to configure the runtime to listen on a different TCP port.
+- Set `LOCAL_LAMBDA_HOST` to configure the local server to listen on a different TCP address.
+- Set `LOCAL_LAMBDA_PORT` to configure the local server to listen on a different TCP port.
+- Set `LOCAL_LAMBDA_INVOCATION_ENDPOINT` to force the local server to listen on a different endpoint.
 
 Example:
 
 ```sh
-LOCAL_LAMBDA_PORT=7777 swift run
+LOCAL_LAMBDA_PORT=8080 LOCAL_LAMBDA_INVOCATION_ENDPOINT=/2015-03-31/functions/function/invocations swift run
 ```
 
 ## Deploying your Swift Lambda functions