Debug a CorDapp

There are several ways you can debug your CorDapp.

Method 1: Use a MockNetwork

You can attach the IntelliJ IDEA debugger to a MockNetwork to debug your CorDapp.

1. Define your flow tests.
2. Set threadPerNode to false in your MockNetwork.
3. Set your breakpoints.
4. Run the flow tests using the debugger. When the tests hit a breakpoint, execution will pause.

Method 2: Use the node driver

Attach the IntelliJ IDEA debugger to nodes running via the node driver to debug your CorDapp. You can debug the CorDapp:

• While the nodes are in-process
• Using remote debugging

Debug with the nodes in-process

1. Define a network using the node driver.
2. Check your DriverParameters and make sure that startNodesInProcess is set to true.
3. Run the driver using the debugger.
4. Set your breakpoints.
5. Interact with your nodes. If the execution hits a breakpoint, it will pause.

Debug remotely

1. Define a network using the node driver.

2. Check your DriverParameters and make sure that startNodesInProcess is set to false and isDebug is set to true.

3. Run the driver. The remote debug ports for each node are generated automatically and printed to the terminal.

   For example:

[INFO ] 11:39:55,471 [driver-pool-thread-0] (DriverDSLImpl.kt:814) internal.DriverDSLImpl.startOutOfProcessNode -
    Starting out-of-process Node PartyA, debug port is 5008, jolokia monitoring port is not enabled {}

4. Attach the debugger to the relevant node’s debug port:

   1. In IntelliJ IDEA, create a new run/debug configuration of type Remote.
   2. Set the run/debug configuration’s Port to the debug port.
   3. Start the run/debug configuration in debug mode.

5. Set your breakpoints.

6. Interact with your node. If the execution hits a breakpoint, it will pause.

Method 3: Enable remote debugging on a node

See Enabling remote debugging.