Skip to content

Debug PySiddhi

Siddhi Queries can be debugged at run time via PySiddhi. It suppots following features with its Python APIs.

  • Add Siddhi Debugger Callbacks
  • Acquiring and Releasing Breakpoints in Siddhi Queries
  • Querying details about Siddhi Query State
  • Debugging Multi-threaded Siddhi Apps

Using Breakpoints and Siddhi Debugger Callbacks

Using Siddhi Debugger, it is possible to break the query execution on occurrences of designated events (input or output events) and analyze the state of the query. Placing a breakpoint would cause Siddhi Debugger Callback to be triggered whenever a breakpoint is reached. The following code snippet demonstrates a basic usage of Siddhi Debugger.

# Obtain siddhi debugger from Siddhi App Runtime.
siddhiDebugger = siddhiAppRuntime.debug()

# Place a breakpoint.
siddhiDebugger.acquireBreakPoint("query 1", SiddhiDebugger.QueryTerminal.IN)

# Setup a callback to receive debug events.
class SiddhiDebuggerCallbackImpl(SiddhiDebuggerCallback):
    def debugEvent(self, event, queryName,queryTerminal, debugger):"Query: " + queryName + ":" +

        # Do assertions on event and check for special cases.

        # Obtain next debuggable element of breakpoint.
        # Alternatively can call to ignore pending
        # debuggable elements and continue from breakpoint.

# Assign the debugger callback

# Send test inputs using inputHandler
inputHandler.send(["WSO2", 50.0, 60])
inputHandler.send(["WSO2", 70.0, 40])

For the complete code on above example and many other examples refer Siddhi Debugger Tests.