implement empty methods in LambdaContext (#66)

Author: Serkan ÖZAL

src/main/java/cloud/localstack/LambdaContext.java

@@ -5,76 +5,116 @@
 import com.amazonaws.services.lambda.runtime.Context;
 import com.amazonaws.services.lambda.runtime.LambdaLogger;
 
+import java.text.SimpleDateFormat;
+import java.util.Date;
+import java.util.UUID;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 
 public class LambdaContext implements Context {
 
-	private final Logger LOG = Logger.getLogger(LambdaContext.class.getName());
+	private static final int DEFAULT_MEMORY_SIZE_IN_MB = 256;
+	private static final String DEFAULT_ACCOUNT_ID = "123456789012";
+	private static final String DEFAULT_REGION = "us-east-1";
+	private static final String DEFAULT_FUNCTION_NAME = "localstack";
+	private static final String DEFAULT_FUNCTION_VERSION = "$LATEST";
 
-	public LambdaLogger getLogger() {
-		return new LambdaLogger() {
+	private static final String TODAY = new SimpleDateFormat("yyyy/MM/dd").format(new Date());
+	private static final String CONTAINER_ID = UUID.randomUUID().toString();
 
-			@Override
-			public void log(String msg) {
-				LOG.log(Level.INFO, msg);
-			}
+	private final Logger LOG = Logger.getLogger(LambdaContext.class.getName());
 
-			@Override
-			public void log(byte[] msg) {
-				log(new String(msg));
-			}
-		};
-	}
+	private final String requestId;
 
-	public String getAwsRequestId() {
-		// TODO Auto-generated method stub
-		return null;
+	public LambdaContext(String requestId) {
+		this.requestId = requestId;
 	}
 
-	public ClientContext getClientContext() {
-		// TODO Auto-generated method stub
-		return null;
+	@Override
+	public String getAwsRequestId() {
+		return requestId;
 	}
 
+	@Override
 	public String getFunctionName() {
-		// TODO Auto-generated method stub
-		return null;
+		String functionName = System.getenv("AWS_LAMBDA_FUNCTION_NAME");
+		if (functionName == null) {
+			functionName = DEFAULT_FUNCTION_NAME;
+		}
+		return functionName;
 	}
 
+	@Override
 	public String getFunctionVersion() {
-		// TODO Auto-generated method stub
-		return null;
-	}
-
-	public CognitoIdentity getIdentity() {
-		// TODO Auto-generated method stub
-		return null;
+		String functionVersion = System.getenv("AWS_LAMBDA_FUNCTION_VERSION");
+		if (functionVersion == null) {
+			functionVersion = DEFAULT_FUNCTION_VERSION;
+		}
+		return functionVersion;
 	}
 
+	@Override
 	public String getInvokedFunctionArn() {
-		// TODO Auto-generated method stub
-		return null;
+		String region = System.getenv("AWS_REGION");
+		if (region == null) {
+			region = DEFAULT_REGION;
+		}
+		return String.format("arn:aws:%s:%s:function:%s:%s",
+				region, DEFAULT_ACCOUNT_ID, getFunctionName(), getFunctionVersion());
 	}
 
+	@Override
 	public String getLogGroupName() {
-		// TODO Auto-generated method stub
-		return null;
+		return String.format("/aws/lambda/%s", getFunctionName());
 	}
 
+	@Override
 	public String getLogStreamName() {
-		// TODO Auto-generated method stub
-		return null;
+		return String.format("%s[%s]%s", TODAY, getFunctionVersion(), CONTAINER_ID);
 	}
 
+	@Override
 	public int getMemoryLimitInMB() {
-		// TODO Auto-generated method stub
-		return 0;
+		String memorySize = System.getenv("AWS_LAMBDA_FUNCTION_MEMORY_SIZE");
+		if (memorySize == null) {
+			return DEFAULT_MEMORY_SIZE_IN_MB;
+		} else {
+			try {
+				return Integer.parseInt(memorySize);
+			} catch (NumberFormatException e) {
+				return DEFAULT_MEMORY_SIZE_IN_MB;
+			}
+		}
 	}
 
+	@Override
 	public int getRemainingTimeInMillis() {
-		// TODO Auto-generated method stub
-		return 0;
+		return Integer.MAX_VALUE;
+	}
+
+	@Override
+	public LambdaLogger getLogger() {
+		return new LambdaLogger() {
+			@Override
+			public void log(String msg) {
+				LOG.log(Level.INFO, msg);
+			}
+
+			@Override
+			public void log(byte[] msg) {
+				log(new String(msg));
+			}
+		};
+	}
+
+	@Override
+	public ClientContext getClientContext() {
+		return null;
+	}
+
+	@Override
+	public CognitoIdentity getIdentity() {
+		return null;
 	}
 
 }

src/main/java/cloud/localstack/LambdaExecutor.java

@@ -29,6 +29,7 @@
 import java.util.List;
 import java.util.Map;
 import java.util.Optional;
+import java.util.UUID;
 import java.util.stream.Collectors;
 
 /**
@@ -89,7 +90,7 @@ public static void main(String[] args) throws Exception {
 			}
 		}
 
-		Context ctx = new LambdaContext();
+		Context ctx = new LambdaContext(UUID.randomUUID().toString());
 		if (handler instanceof RequestHandler) {
 			Object result = ((RequestHandler<Object, ?>) handler).handleRequest(inputObject, ctx);
 			// try turning the output into json