Start/restart poll job when created or updated

This currently contains the logic for restarting updated jobs,
but nothing exercises this logic. The logic for starting polling
for a newly created pipeline is implemented.

poll/poll.go

@@ -1,17 +1,18 @@
 package poll
 
 import (
+	"context"
 	"time"
 
-	"github.com/google/uuid"
-	"github.com/op/go-logging"
-
 	"git.ohea.xyz/cursorius/server/config"
 	"git.ohea.xyz/cursorius/server/database"
 	"git.ohea.xyz/cursorius/server/pipeline_executor"
+
 	"github.com/go-git/go-git/v5"
 	"github.com/go-git/go-git/v5/plumbing"
 	"github.com/go-git/go-git/v5/storage/memory"
+	"github.com/google/uuid"
+	"github.com/op/go-logging"
 )
 
 var log = logging.MustGetLogger("cursorius-server")
@@ -26,13 +27,27 @@ type tag struct {
 	commitHash string
 }
 
-func pollJob(pipeline database.Pipeline, pipelineConf config.PipelineConf, db database.Database) {
+func pollJob(ctx context.Context, pipeline database.Pipeline, pipelineConf config.PipelineConf, db database.Database) {
 	firstScan := true
 	for {
 		// Don't sleep on first scan to ease testing
 		// TODO: this should be replaced with a script that mocks a webhook
 		if !firstScan {
-			time.Sleep(time.Duration(pipeline.PollInterval) * time.Second)
+
+			ctx, cancel := context.WithTimeout(ctx, time.Duration(pipeline.PollInterval)*time.Second)
+
+			select {
+			case <-ctx.Done():
+				switch ctx.Err() {
+				case context.Canceled:
+					log.Infof("Polling for pipeline %v canceled, stopping", pipeline.Name)
+					cancel()
+					return
+				}
+			}
+
+			cancel()
+
 			log.Infof("Polling repo %v", pipeline.Name)
 		} else {
 			firstScan = false
@@ -136,11 +151,17 @@ func launchPollJobs(conf config.PipelineConf, db database.Database, pollChan cha
 		return
 	}
 
+	pipelineCancelations := make(map[uuid.UUID]context.CancelFunc)
+
 	for _, pipeline := range pipelines {
 		if pipeline.PollInterval == 0 {
 			continue
 		} else {
-			go pollJob(pipeline, conf, db)
+			log.Infof("Starting polling for pipeline %v with id %v", pipeline.Name, pipeline.Id)
+			ctx, cancel := context.WithCancel(context.Background())
+			pipelineCancelations[pipeline.Id] = cancel
+
+			go pollJob(ctx, pipeline, conf, db)
 		}
 	}
 
@@ -151,8 +172,17 @@ func launchPollJobs(conf config.PipelineConf, db database.Database, pollChan cha
 			log.Errorf("Could not get pipeline with id \"%v\" from database: %v", err)
 			continue
 		}
-		// TODO: stop existing polling process for given uuid
-		go pollJob(pipeline, conf, db)
+
+		// Cancel existing polling job if it exists
+		if cancelFunc, ok := pipelineCancelations[pipeline.Id]; ok {
+			cancelFunc()
+		}
+
+		// Start new polling job
+		log.Infof("Starting polling for pipeline %v with id %v", pipeline.Name, pipeline.Id)
+		ctx, cancel := context.WithCancel(context.Background())
+		pipelineCancelations[pipeline.Id] = cancel
+		go pollJob(ctx, pipeline, conf, db)
 	}
 
 }