Effectively once not yet supported in Python (#278)

pulsar-functions/cli/src/main/java/org/apache/pulsar/admin/cli/CmdFunctions.java

@@ -215,7 +215,7 @@ public class CmdFunctions extends CmdBase {
                 functionConfigBuilder.setRuntime(FunctionConfig.Runtime.JAVA);
                 userCodeFile = jarFile;
             } else if (null != pyFile) {
-                // Can we do any checks here?
+                doPythonSubmitChecks(functionConfigBuilder);
                 functionConfigBuilder.setRuntime(FunctionConfig.Runtime.PYTHON);
                 userCodeFile = pyFile;
             } else {
@@ -365,6 +365,12 @@ public class CmdFunctions extends CmdBase {
             }
         }
 
+        private void doPythonSubmitChecks(FunctionConfig.Builder functionConfigBuilder) {
+            if (functionConfigBuilder.getProcessingGuarantees() == FunctionConfig.ProcessingGuarantees.EFFECTIVELY_ONCE) {
+                throw new RuntimeException("Effectively once not yet supported in python");
+            }
+        }
+
         private void inferMissingArguments(FunctionConfig.Builder builder) {
             if (builder.getName() == null || builder.getName().isEmpty()) {
                 inferMissingFunctionName(builder);