Added Context.getRemainingTime() back in.

- Renamed `Invocation.deadline` to `Invocation.deadlineInMillisSinceEpoch` to better reflect meaning.
- Added a test for `Context.getRemainingTime()`

Author: fabianfett

Sources/SwiftAwsLambda/Lambda.swift

@@ -118,6 +118,14 @@ public enum Lambda {
             logger[metadataKey: "awsTraceId"] = .string(traceId)
             self.logger = logger
         }
+
+        public func getRemainingTime() -> TimeAmount {
+            let deadline = self.deadline.millisSinceEpoch
+            let now = DispatchWallTime.now().millisSinceEpoch
+
+            let remaining = deadline - now
+            return .milliseconds(remaining)
+        }
     }
 
     private final class Lifecycle {

Sources/SwiftAwsLambda/LambdaRunner.swift

@@ -130,7 +130,7 @@ private extension Lambda.Context {
         self.init(requestId: invocation.requestId,
                   traceId: invocation.traceId,
                   invokedFunctionArn: invocation.invokedFunctionArn,
-                  deadline: DispatchWallTime(millisSinceEpoch: invocation.deadline),
+                  deadline: DispatchWallTime(millisSinceEpoch: invocation.deadlineInMillisSinceEpoch),
                   cognitoIdentity: invocation.cognitoIdentity,
                   clientContext: invocation.clientContext,
                   logger: logger)

Sources/SwiftAwsLambda/LambdaRuntimeClient.swift

@@ -181,7 +181,7 @@ private extension HTTPClient.Response {
 
 internal struct Invocation {
     let requestId: String
-    let deadline: Int64
+    let deadlineInMillisSinceEpoch: Int64
     let invokedFunctionArn: String
     let traceId: String
     let clientContext: String?
@@ -206,7 +206,7 @@ internal struct Invocation {
         }
 
         self.requestId = requestId
-        self.deadline = unixTimeInMilliseconds
+        self.deadlineInMillisSinceEpoch = unixTimeInMilliseconds
         self.invokedFunctionArn = invokedFunctionArn
         self.traceId = traceId
         self.clientContext = headers["Lambda-Runtime-Client-Context"].first

Tests/SwiftAwsLambdaTests/LambdaTest.swift

@@ -252,6 +252,19 @@ class LambdaTest: XCTestCase {
                                             logger: logger)
         XCTAssertLessThan(expiredContext.deadline, .now())
     }
+
+    func testGetRemainingTime() {
+        let logger = Logger(label: "test")
+        let context = Lambda.Context(requestId: UUID().uuidString,
+                                     traceId: UUID().uuidString,
+                                     invokedFunctionArn: UUID().uuidString,
+                                     deadline: .now() + .seconds(1),
+                                     cognitoIdentity: nil,
+                                     clientContext: nil,
+                                     logger: logger)
+        XCTAssertLessThanOrEqual(context.getRemainingTime(), .seconds(1))
+        XCTAssertGreaterThan(context.getRemainingTime(), .milliseconds(800))
+    }
 }
 
 private struct Behavior: LambdaServerBehavior {