// programLoop runs the program being debugged to completion. When a breakpoint's // conditions are satisfied, it sends an Update RPC to the Debuglet Controller. // The function returns when the program exits and all Update RPCs have finished. func programLoop(c *debuglet.Controller, bs *breakpoints.BreakpointStore, prog debug.Program) { var wg sync.WaitGroup for { // Run the program until it hits a breakpoint or exits. status, err := prog.Resume() if err != nil { break } // Get the breakpoints at this address whose conditions were satisfied, // and remove the ones that aren't logpoints. bps := bs.BreakpointsAtPC(status.PC) bps = bpsWithConditionSatisfied(bps, prog) for _, bp := range bps { if bp.Action != "LOG" { bs.RemoveBreakpoint(bp) } } if len(bps) == 0 { continue } // Evaluate expressions and get the stack. vc := valuecollector.NewCollector(prog, maxCapturedVariables) needStackFrames := false for _, bp := range bps { // If evaluating bp's condition didn't return an error, evaluate bp's // expressions, and later get the stack frames. if bp.Status == nil { bp.EvaluatedExpressions = expressionValues(bp.Expressions, prog, vc) needStackFrames = true } } var ( stack []*cd.StackFrame stackFramesStatusMessage *cd.StatusMessage ) if needStackFrames { stack, stackFramesStatusMessage = stackFrames(prog, vc) } // Read variable values from the program. variableTable := vc.ReadValues() // Start a goroutine to send updates to the Debuglet Controller or write // to logs, concurrently with resuming the program. // TODO: retry Update on failure. for _, bp := range bps { wg.Add(1) switch bp.Action { case "LOG": go func(format string, evaluatedExpressions []*cd.Variable) { s := valuecollector.LogString(format, evaluatedExpressions, variableTable) log.Print(s) wg.Done() }(bp.LogMessageFormat, bp.EvaluatedExpressions) bp.Status = nil bp.EvaluatedExpressions = nil default: go func(bp *cd.Breakpoint) { defer wg.Done() bp.IsFinalState = true if bp.Status == nil { // If evaluating bp's condition didn't return an error, include the // stack frames, variable table, and any status message produced when // getting the stack frames. bp.StackFrames = stack bp.VariableTable = variableTable bp.Status = stackFramesStatusMessage } if err := c.Update(bp.Id, bp); err != nil { log.Printf("Failed to send breakpoint update for %s: %s", bp.Id, err) } }(bp) } } } // Wait for all updates to finish before returning. wg.Wait() }