Proper shutdown.

cmd.go

@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"os"
 	"os/signal"
+	"syscall"
 	"time"
 
 	"github.com/alexcesaro/log"
@@ -94,24 +95,22 @@ func main() {
 		return
 	}
 
-	isActive := true
+	resultChan := make(chan Result)
 
 	// Construct interrupt handler
 	sig := make(chan os.Signal, 1)
-	signal.Notify(sig, os.Interrupt)
+	signal.Notify(sig, os.Interrupt, syscall.SIGTERM)
 	go func() {
 		<-sig // Wait for ^C signal
 		logger.Warningf("Interrupt signal detected, shutting down gracefully by waiting for active workers to finish.")
 		crawler.Shutdown()
 
-		// FIXME: This isn't working?
 		<-sig // Hurry up?
-		logger.Warningf("Super-interrupt. Abandoning in-progress workers.")
+		logger.Warningf("Urgent interrupt. Abandoning in-progress workers.")
-		isActive = false
+		close(resultChan) // FIXME: Could this cause stuff to asplode?
 	}()
 
 	// Launch crawler
-	resultChan := make(chan Result)
 	go crawler.Run(resultChan, options.Concurrency)
 	logger.Infof("Crawler started with %d concurrency limit.", options.Concurrency)
 
@@ -139,11 +138,6 @@ func main() {
 			logger.Infof("StopAfter count reached, shutting down gracefully.")
 			crawler.Shutdown()
 		}
-
-		if !isActive {
-			// No time to wait, finish writing and quit.
-			break
-		}
 	}
 
 	w.Write([]byte("]")) // No error checking here because it's too late to care.

crawler.go

@@ -31,6 +31,7 @@ func NewCrawler(client *Client, seeds []string, peerAge time.Duration) *Crawler
 		client:     client,
 		seenFilter: map[string]bool{},
 		peerAge:    peerAge,
+		shutdown:   make(chan struct{}, 1),
 	}
 	filter := func(address string) *string {
 		return c.filter(address)
@@ -187,6 +188,7 @@ func (c *Crawler) Run(resultChan chan<- Result, numWorkers int) {
 			<-workerChan
 
 		case <-c.shutdown:
+			logger.Infof("Shutting down.")
 			isActive = false
 		}
 	}