Handle peer KEEPALIVE messages in chaincode message handler. (#513)

The Node.js shim exited when the peer sent KEEPALIVE (type 18) on idle
connections, which breaks long-running chaincode such as CCAAS. Echo
KEEPALIVE back to the peer and align behaviour with the Go chaincode
shim.

Signed-off-by: Jakub Dzikowski <jakub.t.dzikowski@gmail.com>

Author: dzikowski

libraries/fabric-shim/lib/handler.js

@@ -35,6 +35,7 @@ const MSG_TYPE = {
     INIT: peer.ChaincodeMessage.Type.INIT,
     TRANSACTION: peer.ChaincodeMessage.Type.TRANSACTION,
     COMPLETED: peer.ChaincodeMessage.Type.COMPLETED,
+    KEEPALIVE: peer.ChaincodeMessage.Type.KEEPALIVE,
 };
 
 /*
@@ -295,6 +296,12 @@ class ChaincodeMessageHandler {
         stream.on('data', (msgpb) => {
             const msg = mapFromChaincodeMessage(msgpb);
             logger.debug(util.format('Received chat message from peer: %s, state: %s, type: %s', msg.txid, state, msg.type));
+
+            if (msg.type === MSG_TYPE.KEEPALIVE) {
+                stream.write(msgpb);
+                return;
+            }
+
             if (state === STATES.Ready) {
                 const type = msg.type;
 

libraries/fabric-shim/test/unit/handler.js

@@ -783,6 +783,41 @@ describe('Handler', () => {
                     expect(handleTransactionSpy.firstCall.args).to.deep.equal([mapFromChaincodeMessage(readyMsg)]);
                 });
 
+                it ('should echo KEEPALIVE when in state ready and MSG_TYPE equals KEEPALIVE', () => {
+                    const processStub = sinon.stub(process, 'exit');
+
+                    eventReg.data(registeredMsg);
+                    eventReg.data(establishedMsg);
+
+                    const keepaliveMsg = mapToChaincodeMessage({
+                        type: MSG_TYPE.KEEPALIVE
+                    });
+
+                    eventReg.data(keepaliveMsg);
+
+                    expect(mockStream.write.calledTwice).to.be.true;
+                    expect(mockStream.write.secondCall.args).to.deep.equal([keepaliveMsg]);
+                    expect(mockNewErrorMsg.notCalled).to.be.true;
+                    expect(handleMsgResponseSpy.notCalled).to.be.true;
+                    expect(handleInitSpy.notCalled).to.be.true;
+                    expect(handleTransactionSpy.notCalled).to.be.true;
+                    expect(processStub.notCalled).to.be.true;
+
+                    processStub.restore();
+                });
+
+                it ('should echo KEEPALIVE when in state created and MSG_TYPE equals KEEPALIVE', () => {
+                    const keepaliveMsg = mapToChaincodeMessage({
+                        type: MSG_TYPE.KEEPALIVE
+                    });
+
+                    eventReg.data(keepaliveMsg);
+
+                    expect(mockStream.write.calledTwice).to.be.true;
+                    expect(mockStream.write.secondCall.args).to.deep.equal([keepaliveMsg]);
+                    expect(mockNewErrorMsg.notCalled).to.be.true;
+                });
+
                 it ('should end the process with value 1', () => {
                     const processStub = sinon.stub(process, 'exit');