WIP adding logframer and tests to fdk-java, before each function invocation

Author: nishalad95

runtime/src/main/java/com/fnproject/fn/runtime/MethodFunctionInvoker.java

@@ -17,6 +17,27 @@
  */
 public class MethodFunctionInvoker implements FunctionInvoker {
 
+    /*
+    * If enabled, print the logging framing content
+    */
+    public void logFramer(FunctionRuntimeContext rctx, InputEvent evt) {
+        String framer = rctx.getConfigurationByKey("FN_LOGFRAME_NAME").orElse("");
+        
+        if (framer != "") {
+            String valueSrc = rctx.getConfigurationByKey("FN_LOGFRAME_HDR").orElse("");
+            
+            if (valueSrc != "") {
+                String id = evt.getHeaders().get(valueSrc).orElse("");
+                if (id != "") {
+                    System.out.println(framer + "=" + id);
+                    System.err.println(framer + "=" + id);
+                }
+            }
+        }
+    
+    }
+    
+    
     /**
      * Invoke the function wrapped by this loader
      *
@@ -33,6 +54,8 @@ public Optional<OutputEvent> tryInvoke(InvocationContext ctx, InputEvent evt) th
 
         Object rawResult;
 
+        logFramer(runtimeContext, evt);
+
         try {
             rawResult = method.getTargetMethod().invoke(ctx.getRuntimeContext().getInvokeInstance().orElse(null), userFunctionParams);
         } catch (IllegalAccessException | InvocationTargetException e) {

testing-junit4/src/test/java/com/fnproject/fn/testing/FnTestingRuleTest.java

@@ -250,6 +250,22 @@ public void shouldHandleBodyAsInputStream() throws IOException {
         Assertions.assertThat(capturedBodies.get(0)).isEqualTo("FOO BAR".getBytes());
     }
 
+    @Test
+    public void shouldPrintLogFrame() throws Exception {
+        fn.setConfig("FN_LOGFRAME_NAME", "containerID");
+        fn.setConfig("FN_LOGFRAME_HDR", "fnID");
+        fn.givenEvent().withBody("Hello World").enqueue();
+
+        fn.thenRun(TestFn.class, "copyConfiguration");
+        Assertions.assertThat(configuration).containsEntry("FN_LOGFRAME_NAME", "containerID");
+        Assertions.assertThat(configuration).containsEntry("FN_LOGFRAME_HDR", "fnID");
+        
+        FnResult result = fn.getOnlyResult();
+        Assertions.assertThat(result.getBodyAsString()).isEqualTo("containerID=fnID\nHello World");
+        // assertThat(fn.getOnlyOutputAsString()).isEqualTo("containerID=fnID\nHello World");
+    }
+
+
     // TODO move this to HTTP gateway
 //    @Test
 //    public void shouldLeaveQueryParamtersOffIfNotSpecified() {