println connected

.gitignore

@@ -2,3 +2,4 @@
 /cmd/pg-lo-demo/pg-lo-demo
 /cmd/pg-pulse/pg-pulse
 /cmd/pg-walspam/pg-walspam
+/cmd/pg-template

cmd/.template/main.go

@@ -0,0 +1,45 @@
+package main
+
+import (
+	"context"
+	"database/sql"
+	"flag"
+	"log"
+	"os"
+	"time"
+
+	"pg/src/with"
+
+	_ "github.com/lib/pq"
+)
+
+func main() {
+	if err := with.Context(run); err != nil {
+		panic(err)
+	}
+}
+
+func run(ctx context.Context) error {
+	fs := flag.NewFlagSet(os.Args[0], flag.ContinueOnError)
+	c := fs.String("c", "postgresql://pulsegres:pulsegres@localhost:15432", "conn string")
+	if err := fs.Parse(os.Args[1:]); err != nil {
+		panic(err)
+	}
+
+	return with.PSQL(ctx, *c, func(pg *sql.DB) error {
+		go with.Every(ctx, 5*time.Second, func() {
+			row := pg.QueryRowContext(ctx, `SELECT 1`)
+			var n int
+			if err := row.Err(); err != nil {
+				log.Println("query err:", err)
+			} else if err := row.Scan(&n); err != nil {
+				log.Println("scan err:", err)
+			} else {
+				log.Println("ping...")
+			}
+		})
+
+		<-ctx.Done()
+		return nil
+	})
+}

cmd/generate.go

@@ -0,0 +1,3 @@
+package main
+
+//go:generate sh -c "if ! [ -d ./pg-template ]; then cp -r ./.template ./pg-template; fi"

cmd/pg-queue/README.md

@@ -0,0 +1 @@
+https://topicpartition.io/blog/postgres-pubsub-queue-benchmarks

cmd/pg-queue/main.go

@@ -0,0 +1,31 @@
+package main
+
+import (
+	"context"
+	"database/sql"
+	"flag"
+	"os"
+
+	"pg/src/with"
+
+	_ "github.com/lib/pq"
+)
+
+func main() {
+	if err := with.Context(run); err != nil {
+		panic(err)
+	}
+}
+
+func run(ctx context.Context) error {
+	fs := flag.NewFlagSet(os.Args[0], flag.ContinueOnError)
+	c := fs.String("c", "postgresql://pulsegres:pulsegres@localhost:15432", "conn string")
+	if err := fs.Parse(os.Args[1:]); err != nil {
+		panic(err)
+	}
+
+	return with.PSQL(ctx, *c, func(pg *sql.DB) error {
+		<-ctx.Done()
+		return nil
+	})
+}

src/with/pg.go

@@ -42,10 +42,14 @@ func PSQL(ctx context.Context, conn string, foo func(db *sql.DB) error) error {
 				if ok {
 					return
 				}
-			case <-time.After(time.Second * 5):
+			}
+			select {
+			case <-ctx.Done():
+			case <-time.After(time.Second):
 			}
 		}
 	}()
+	log.Println("connected")
 
 	return foo(pg)
 }