pulse more boilerplate refactoring

.gitignore

@@ -1 +1,4 @@
 **/*.sw*
+/cmd/pg-lo-demo/pg-lo-demo
+/cmd/pg-pulse/pg-pulse
+/cmd/pg-walspam/pg-walspam

cmd/pg-lo-demo/main.go

@@ -4,8 +4,6 @@ import (
 	"context"
 	"database/sql"
 	"flag"
-	"fmt"
-	"log"
 	"os"
 	"time"
 
@@ -29,119 +27,6 @@ func run(ctx context.Context) error {
 	}
 
 	return with.PSQL(ctx, *c, func(pg *sql.DB) error {
-		log.Println("staging...")
-		if _, err := pg.ExecContext(ctx, `
-	   	DROP TABLE IF EXISTS "pg-pulse";
-	   	CREATE TABLE IF NOT EXISTS "pg-pulse" (k TEXT);
-	   `); err != nil {
-			return err
-		}
-
-		log.Println("spamming...")
-
-		var downtime time.Duration
-		okc := make(chan bool)
-		defer close(okc)
-		go func() {
-			lastOK := true
-			wasOK := time.Now()
-			for ok := range okc {
-				if isNewlyOK := ok && !lastOK; isNewlyOK {
-					downtime += time.Since(wasOK)
-				}
-				lastOK = ok
-				if ok {
-					wasOK = time.Now()
-				}
-			}
-		}()
-		pushOK := func(v bool) {
-			select {
-			case okc <- v:
-			default:
-			}
-		}
-
-		pticker := time.NewTicker(5 * time.Second)
-		defer pticker.Stop()
-		ticker := time.NewTicker(*d)
-		defer ticker.Stop()
-		n := uint(0)
-		isHA := false
-		isHA0 := false
-		for ctx.Err() == nil {
-			func() {
-				ctx, can := context.WithCancel(ctx)
-				defer can()
-
-				done := make(chan struct{})
-				go func() {
-					defer close(done)
-
-					if _, err := pg.ExecContext(ctx, fmt.Sprintf(`
-	   				INSERT INTO "pg-pulse" (k) SELECT substr(md5(random()::text), 1, 25)
-	   			`)); err != nil {
-						pushOK(false)
-						log.Println("\n! failed nonzero insert:", err)
-					} else {
-						n += 1
-						pushOK(true)
-					}
-
-					var lostWrites uint
-					ha, ha1 := false, false
-					row := pg.QueryRowContext(ctx, `
-	   				SELECT
-	   					(
-	   						SELECT COUNT(*) > 0
-	   						FROM pg_replication_slots
-	   						WHERE slot_name LIKE 'dpg_%_a_ha__'
-	   					) AS is_ha,
-	   					(
-	   						SELECT COUNT(*) > 0
-	   						FROM pg_replication_slots
-	   						WHERE slot_name LIKE 'dpg_%_a_ha_0'
-	   					) AS is_ha1,
-	   					(
-	   						SELECT $1 - COUNT(*)
-	   						FROM "pg-pulse"
-	   					) AS lost_writes
-	   			`, n)
-					if err := row.Err(); err != nil {
-						log.Println("\n! failed getting ha-stuff:", err)
-					} else if err := row.Scan(&ha, &ha1, &lostWrites); err != nil {
-						log.Println("\n! failed scanning ha-stuff:", err)
-					} else {
-						isHA = isHA || ha
-						isHA0 = isHA && !ha1
-					}
-
-					ctx, can = context.WithTimeout(ctx, time.Second*5)
-					defer can()
-
-					select {
-					case <-pticker.C:
-						using := ""
-						if isHA && isHA0 {
-							using = "using ha0"
-						} else if isHA && !isHA0 {
-							using = "using ha1"
-						}
-						log.Printf("%v writes (%v lost) (%v down) %s", n, lostWrites, downtime.Round(time.Second), using)
-					default:
-					}
-				}()
-
-				select {
-				case <-ctx.Done():
-				case <-done:
-				}
-			}()
-			select {
-			case <-ctx.Done():
-			case <-ticker.C:
-			}
-		}
 		return ctx.Err()
 	})
 }

cmd/pg-pulse/main.go

@@ -62,86 +62,58 @@ func run(ctx context.Context) error {
 			}
 		}
 
-		pticker := time.NewTicker(5 * time.Second)
-		defer pticker.Stop()
-		ticker := time.NewTicker(*d)
-		defer ticker.Stop()
 		n := uint(0)
 		isHA := false
 		isHA0 := false
-		for ctx.Err() == nil {
+		var lostWrites uint
-			func() {
+		go with.Every(ctx, 5*time.Second, func() {
-				ctx, can := context.WithCancel(ctx)
+			using := ""
-				defer can()
+			if isHA && isHA0 {
-
+				using = "using ha0"
-				done := make(chan struct{})
+			} else if isHA && !isHA0 {
-				go func() {
+				using = "using ha1"
-					defer close(done)
-
-					if _, err := pg.ExecContext(ctx, fmt.Sprintf(`
-	   				INSERT INTO "pg-pulse" (k) SELECT substr(md5(random()::text), 1, 25)
-	   			`)); err != nil {
-						pushOK(false)
-						log.Println("\n! failed nonzero insert:", err)
-					} else {
-						n += 1
-						pushOK(true)
-					}
-
-					var lostWrites uint
-					ha, ha1 := false, false
-					row := pg.QueryRowContext(ctx, `
-	   				SELECT
-	   					(
-	   						SELECT COUNT(*) > 0
-	   						FROM pg_replication_slots
-	   						WHERE slot_name LIKE 'dpg_%_a_ha__'
-	   					) AS is_ha,
-	   					(
-	   						SELECT COUNT(*) > 0
-	   						FROM pg_replication_slots
-	   						WHERE slot_name LIKE 'dpg_%_a_ha_0'
-	   					) AS is_ha1,
-	   					(
-	   						SELECT $1 - COUNT(*)
-	   						FROM "pg-pulse"
-	   					) AS lost_writes
-	   			`, n)
-					if err := row.Err(); err != nil {
-						log.Println("\n! failed getting ha-stuff:", err)
-					} else if err := row.Scan(&ha, &ha1, &lostWrites); err != nil {
-						log.Println("\n! failed scanning ha-stuff:", err)
-					} else {
-						isHA = isHA || ha
-						isHA0 = isHA && !ha1
-					}
-
-					ctx, can = context.WithTimeout(ctx, time.Second*5)
-					defer can()
-
-					select {
-					case <-pticker.C:
-						using := ""
-						if isHA && isHA0 {
-							using = "using ha0"
-						} else if isHA && !isHA0 {
-							using = "using ha1"
-						}
-						log.Printf("%v writes (%v lost) (%v down) %s", n, lostWrites, downtime.Round(time.Second), using)
-					default:
-					}
-				}()
-
-				select {
-				case <-ctx.Done():
-				case <-done:
-				}
-			}()
-			select {
-			case <-ctx.Done():
-			case <-ticker.C:
 			}
-		}
+			log.Printf("%v writes (%v lost) (%v down) %s", n, lostWrites, downtime.Round(time.Second), using)
+		})
+
+		with.GoEvery(ctx, *d, func() {
+			if _, err := pg.ExecContext(ctx, fmt.Sprintf(`
+	   		INSERT INTO "pg-pulse" (k) SELECT substr(md5(random()::text), 1, 25)
+	   	`)); err != nil {
+				pushOK(false)
+				log.Println("\n! failed nonzero insert:", err)
+			} else {
+				n += 1
+				pushOK(true)
+			}
+
+			ha, ha1 := false, false
+			row := pg.QueryRowContext(ctx, `
+	   		SELECT
+	   			(
+	   				SELECT COUNT(*) > 0
+	   				FROM pg_replication_slots
+	   				WHERE slot_name LIKE 'dpg_%_a_ha__'
+	   			) AS is_ha,
+	   			(
+	   				SELECT COUNT(*) > 0
+	   				FROM pg_replication_slots
+	   				WHERE slot_name LIKE 'dpg_%_a_ha_0'
+	   			) AS is_ha1,
+	   			(
+	   				SELECT $1 - COUNT(*)
+	   				FROM "pg-pulse"
+	   			) AS lost_writes
+	   	`, n)
+			if err := row.Err(); err != nil {
+				log.Println("\n! failed getting ha-stuff:", err)
+			} else if err := row.Scan(&ha, &ha1, &lostWrites); err != nil {
+				log.Println("\n! failed scanning ha-stuff:", err)
+			} else {
+				isHA = isHA || ha
+				isHA0 = isHA && !ha1
+			}
+		})
 		return ctx.Err()
 	})
 }

src/with/every.go

@@ -0,0 +1,34 @@
+package with
+
+import (
+	"context"
+	"time"
+)
+
+func GoEvery(ctx context.Context, d time.Duration, foo func()) {
+	every(ctx, d, foo, true)
+}
+
+func Every(ctx context.Context, d time.Duration, foo func()) {
+	every(ctx, d, foo, false)
+}
+
+func every(ctx context.Context, d time.Duration, foo func(), async bool) {
+	ticker := time.NewTicker(d)
+	defer ticker.Stop()
+	for ctx.Err() == nil {
+		everyTry(ctx, foo, async)
+		select {
+		case <-ctx.Done():
+		case <-ticker.C:
+		}
+	}
+}
+
+func everyTry(ctx context.Context, foo func(), async bool) {
+	if async {
+		go foo()
+	} else {
+		foo()
+	}
+}