very dumb adapter from redis GET, PUT, DEL to SELECT, INSERT ON CONFLICT UPDATE, DELETE

go.mod

@@ -0,0 +1,26 @@
+module red-apter
+
+go 1.24.0
+
+toolchain go1.24.12
+
+require (
+	github.com/lib/pq v1.11.1
+	github.com/redis/go-redis/v9 v9.17.3
+	modernc.org/sqlite v1.44.3
+)
+
+require (
+	github.com/cespare/xxhash/v2 v2.3.0 // indirect
+	github.com/dgryski/go-rendezvous v0.0.0-20200823014737-9f7001d12a5f // indirect
+	github.com/dustin/go-humanize v1.0.1 // indirect
+	github.com/google/uuid v1.6.0 // indirect
+	github.com/mattn/go-isatty v0.0.20 // indirect
+	github.com/ncruces/go-strftime v1.0.0 // indirect
+	github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec // indirect
+	golang.org/x/exp v0.0.0-20251023183803-a4bb9ffd2546 // indirect
+	golang.org/x/sys v0.37.0 // indirect
+	modernc.org/libc v1.67.6 // indirect
+	modernc.org/mathutil v1.7.1 // indirect
+	modernc.org/memory v1.11.0 // indirect
+)

go.sum

@@ -0,0 +1,65 @@
+github.com/bsm/ginkgo/v2 v2.12.0 h1:Ny8MWAHyOepLGlLKYmXG4IEkioBysk6GpaRTLC8zwWs=
+github.com/bsm/ginkgo/v2 v2.12.0/go.mod h1:SwYbGRRDovPVboqFv0tPTcG1sN61LM1Z4ARdbAV9g4c=
+github.com/bsm/gomega v1.27.10 h1:yeMWxP2pV2fG3FgAODIY8EiRE3dy0aeFYt4l7wh6yKA=
+github.com/bsm/gomega v1.27.10/go.mod h1:JyEr/xRbxbtgWNi8tIEVPUYZ5Dzef52k01W3YH0H+O0=
+github.com/cespare/xxhash/v2 v2.3.0 h1:UL815xU9SqsFlibzuggzjXhog7bL6oX9BbNZnL2UFvs=
+github.com/cespare/xxhash/v2 v2.3.0/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
+github.com/dgryski/go-rendezvous v0.0.0-20200823014737-9f7001d12a5f h1:lO4WD4F/rVNCu3HqELle0jiPLLBs70cWOduZpkS1E78=
+github.com/dgryski/go-rendezvous v0.0.0-20200823014737-9f7001d12a5f/go.mod h1:cuUVRXasLTGF7a8hSLbxyZXjz+1KgoB3wDUb6vlszIc=
+github.com/dustin/go-humanize v1.0.1 h1:GzkhY7T5VNhEkwH0PVJgjz+fX1rhBrR7pRT3mDkpeCY=
+github.com/dustin/go-humanize v1.0.1/go.mod h1:Mu1zIs6XwVuF/gI1OepvI0qD18qycQx+mFykh5fBlto=
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+github.com/google/pprof v0.0.0-20250317173921-a4b03ec1a45e/go.mod h1:boTsfXsheKC2y+lKOCMpSfarhxDeIzfZG1jqGcPl3cA=
+github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
+github.com/google/uuid v1.6.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
+github.com/hashicorp/golang-lru/v2 v2.0.7 h1:a+bsQ5rvGLjzHuww6tVxozPZFVghXaHOwFs4luLUK2k=
+github.com/hashicorp/golang-lru/v2 v2.0.7/go.mod h1:QeFd9opnmA6QUJc5vARoKUSoFhyfM2/ZepoAG6RGpeM=
+github.com/lib/pq v1.11.1 h1:wuChtj2hfsGmmx3nf1m7xC2XpK6OtelS2shMY+bGMtI=
+github.com/lib/pq v1.11.1/go.mod h1:/p+8NSbOcwzAEI7wiMXFlgydTwcgTr3OSKMsD2BitpA=
+github.com/mattn/go-isatty v0.0.20 h1:xfD0iDuEKnDkl03q4limB+vH+GxLEtL/jb4xVJSWWEY=
+github.com/mattn/go-isatty v0.0.20/go.mod h1:W+V8PltTTMOvKvAeJH7IuucS94S2C6jfK/D7dTCTo3Y=
+github.com/ncruces/go-strftime v1.0.0 h1:HMFp8mLCTPp341M/ZnA4qaf7ZlsbTc+miZjCLOFAw7w=
+github.com/ncruces/go-strftime v1.0.0/go.mod h1:Fwc5htZGVVkseilnfgOVb9mKy6w1naJmn9CehxcKcls=
+github.com/redis/go-redis/v9 v9.17.3 h1:fN29NdNrE17KttK5Ndf20buqfDZwGNgoUr9qjl1DQx4=
+github.com/redis/go-redis/v9 v9.17.3/go.mod h1:u410H11HMLoB+TP67dz8rL9s6QW2j76l0//kSOd3370=
+github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec h1:W09IVJc94icq4NjY3clb7Lk8O1qJ8BdBEF8z0ibU0rE=
+github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec/go.mod h1:qqbHyh8v60DhA7CoWK5oRCqLrMHRGoxYCSS9EjAz6Eo=
+golang.org/x/exp v0.0.0-20251023183803-a4bb9ffd2546 h1:mgKeJMpvi0yx/sU5GsxQ7p6s2wtOnGAHZWCHUM4KGzY=
+golang.org/x/exp v0.0.0-20251023183803-a4bb9ffd2546/go.mod h1:j/pmGrbnkbPtQfxEe5D0VQhZC6qKbfKifgD0oM7sR70=
+golang.org/x/mod v0.29.0 h1:HV8lRxZC4l2cr3Zq1LvtOsi/ThTgWnUk/y64QSs8GwA=
+golang.org/x/mod v0.29.0/go.mod h1:NyhrlYXJ2H4eJiRy/WDBO6HMqZQ6q9nk4JzS3NuCK+w=
+golang.org/x/sync v0.17.0 h1:l60nONMj9l5drqw6jlhIELNv9I0A4OFgRsG9k2oT9Ug=
+golang.org/x/sync v0.17.0/go.mod h1:9KTHXmSnoGruLpwFjVSX0lNNA75CykiMECbovNTZqGI=
+golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.37.0 h1:fdNQudmxPjkdUTPnLn5mdQv7Zwvbvpaxqs831goi9kQ=
+golang.org/x/sys v0.37.0/go.mod h1:OgkHotnGiDImocRcuBABYBEXf8A9a87e/uXjp9XT3ks=
+golang.org/x/tools v0.38.0 h1:Hx2Xv8hISq8Lm16jvBZ2VQf+RLmbd7wVUsALibYI/IQ=
+golang.org/x/tools v0.38.0/go.mod h1:yEsQ/d/YK8cjh0L6rZlY8tgtlKiBNTL14pGDJPJpYQs=
+modernc.org/cc/v4 v4.27.1 h1:9W30zRlYrefrDV2JE2O8VDtJ1yPGownxciz5rrbQZis=
+modernc.org/cc/v4 v4.27.1/go.mod h1:uVtb5OGqUKpoLWhqwNQo/8LwvoiEBLvZXIQ/SmO6mL0=
+modernc.org/ccgo/v4 v4.30.1 h1:4r4U1J6Fhj98NKfSjnPUN7Ze2c6MnAdL0hWw6+LrJpc=
+modernc.org/ccgo/v4 v4.30.1/go.mod h1:bIOeI1JL54Utlxn+LwrFyjCx2n2RDiYEaJVSrgdrRfM=
+modernc.org/fileutil v1.3.40 h1:ZGMswMNc9JOCrcrakF1HrvmergNLAmxOPjizirpfqBA=
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+modernc.org/sqlite v1.44.3 h1:+39JvV/HWMcYslAwRxHb8067w+2zowvFOUrOWIy9PjY=
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+modernc.org/strutil v1.2.1 h1:UneZBkQA+DX2Rp35KcM69cSsNES9ly8mQWD71HKlOA0=
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+modernc.org/token v1.1.0 h1:Xl7Ap9dKaEs5kLoOQeQmPWevfnk/DM5qcLcYlA8ys6Y=
+modernc.org/token v1.1.0/go.mod h1:UGzOrNV1mAFSEB63lOFHIpNRUVMvYTc6yu1SMY/XTDM=

main.go

@@ -0,0 +1,17 @@
+package main
+
+import (
+	"context"
+	"os/signal"
+	"red-apter/src"
+	"syscall"
+)
+
+func main() {
+	ctx, can := signal.NotifyContext(context.Background(), syscall.SIGINT)
+	defer can()
+
+	if err := src.Main(ctx); err != nil {
+		panic(err)
+	}
+}

src/adapt.go

@@ -0,0 +1,143 @@
+package src
+
+import (
+	"bufio"
+	"bytes"
+	"context"
+	"fmt"
+	"io"
+	"log"
+	"net"
+	"strconv"
+)
+
+func adapt(ctx context.Context, config Config, conn net.Conn) error {
+	reader := bufio.NewReader(conn)
+
+	for ctx.Err() == nil {
+		message, err := readMessage(reader)
+		if err != nil {
+			if err == io.EOF {
+				return nil
+			}
+			return err
+		}
+
+		if len(message) > 0 {
+			var reply string
+			switch message[0] {
+			case "hello":
+				reply = "*0\r\n"
+			case "client":
+				reply = "+OK\r\n"
+			case "ping":
+				reply = "+PONG\r\n"
+			case "set":
+				k := message[1].(string)
+				v := message[2]
+				reply = "+OK\r\n"
+				switch v2 := v.(type) {
+				case []byte:
+					if err := config.db.Put(ctx, 1, k, string(v2)); err != nil {
+						reply = "-" + err.Error() + "\r\n"
+					}
+				case string:
+					if err := config.db.Put(ctx, 1, k, v2); err != nil {
+						reply = "-" + err.Error() + "\r\n"
+					}
+				default:
+					log.Fatalf("not impl: set %T", v)
+				}
+			case "del":
+				k := message[1].(string)
+				reply = "+OK\r\n"
+				if err := config.db.Del(ctx, 1, k); err != nil {
+					reply = "-" + err.Error() + "\r\n"
+				}
+			case "get":
+				v, err := Select[any](ctx, 1, fmt.Sprint(message[1]))
+				if err != nil {
+					reply = "-" + err.Error()
+				} else if v == nil || *v == nil {
+					reply = "_\r\n" // RESP3 null
+				} else {
+					switch v2 := (*v).(type) {
+					case []byte:
+						reply = fmt.Sprintf("+%s\r\n", v2)
+					case string:
+						reply = fmt.Sprintf("+%s\r\n", v2)
+					default:
+						log.Fatalf("not impl: get type %T", v2)
+						return nil
+					}
+				}
+			default:
+				log.Fatalf("unhandled: %+v", message)
+			}
+			log.Printf("replying: %q", reply)
+			if _, err := fmt.Fprintf(conn, reply); err != nil {
+				return err
+			}
+		}
+
+		log.Println()
+	}
+
+	return io.EOF
+}
+
+func readMessage(reader *bufio.Reader) ([]any, error) {
+	firstLine, _, err := reader.ReadLine()
+	log.Printf("%q", firstLine)
+	if err != nil {
+		return nil, err
+	}
+	firstLine = bytes.TrimSuffix(firstLine, []byte("\r\n"))
+	if len(firstLine) == 0 {
+		return nil, nil
+	}
+
+	switch firstLine[0] {
+	case '+': // simple string, like +OK
+		return []any{string(firstLine[1:])}, nil
+	case '-': // simple error, like -message
+		return nil, fmt.Errorf("error: %s", firstLine[1:])
+	case ':': // number, like /[+-][0-9]+/
+		firstLine = bytes.TrimPrefix(firstLine[1:], []byte("+"))
+		n, err := strconv.Atoi(string(firstLine[1:]))
+		return []any{n}, err
+	case '$': // long string, like $-1 for nil, like $LEN\r\nSTRING\r\n
+		if firstLine[1] == '-' {
+			return []any{nil}, nil
+		}
+		nextLine, _, err := reader.ReadLine()
+		log.Printf("%q", nextLine)
+		nextLine = bytes.TrimSuffix(nextLine, []byte("\r\n"))
+		return []any{string(nextLine)}, err
+	case '*': // array, like *-1 for nil, like *4 for [1,2,3,4]
+		n, err := strconv.Atoi(string(firstLine[1:]))
+		if err != nil {
+			return nil, err
+		} else if n == -1 {
+			return nil, nil
+		}
+		var result []any
+		for i := 0; i < n; i++ {
+			more, err := readMessage(reader)
+			if err != nil {
+				return nil, err
+			}
+			result = append(result, more...)
+		}
+		return result, nil
+	case '_': // nil
+		return nil, nil
+	case '#': // boolean, like #t or #f
+		return []any{firstLine[1] == 't'}, nil
+	case ',': // double
+		log.Fatal("not impl")
+	}
+
+	log.Fatalf("not impl: %q", firstLine)
+	return nil, nil
+}

src/config.go

@@ -0,0 +1,52 @@
+package src
+
+import (
+	"context"
+	"encoding/json"
+	"os"
+)
+
+type Config struct {
+	Listen           string `json:"LISTEN"`
+	ConnectionDriver string `json:"CONNECTION_DRIVER"`
+	ConnectionString string `json:"CONNECTION_STRING"`
+	db               DB
+}
+
+func NewConfig(ctx context.Context) (Config, error) {
+	config, err := newConfig()
+	if err != nil {
+		return config, err
+	}
+
+	db, err := NewDB(ctx, config.ConnectionDriver, config.ConnectionString)
+	if err != nil {
+		return config, err
+	}
+	config.db = db
+
+	return config, nil
+}
+
+func newConfig() (Config, error) {
+	config := Config{
+		Listen:           ":10000",
+		ConnectionDriver: "sqlite",
+		ConnectionString: "/tmp/red-apter.db",
+	}
+	b, _ := json.Marshal(config)
+	var m map[string]any
+	if err := json.Unmarshal(b, &m); err != nil {
+		return config, err
+	}
+	for k := range m {
+		if v := os.Getenv(k); v != "" {
+			m[k] = v
+		}
+	}
+	b2, _ := json.Marshal(m)
+	if err := json.Unmarshal(b2, &config); err != nil {
+		return config, err
+	}
+	return config, nil
+}

src/db.go

@@ -0,0 +1,114 @@
+package src
+
+import (
+	"context"
+	"database/sql"
+	"encoding/json"
+
+	_ "github.com/lib/pq"
+	_ "modernc.org/sqlite"
+)
+
+type DB struct {
+	*sql.DB
+}
+
+var global DB
+
+func NewDB(ctx context.Context, driver, conn string) (DB, error) {
+	sql, err := sql.Open(driver, conn)
+	if err != nil {
+		return DB{}, err
+	}
+	db := DB{sql}
+
+	if err := db.setup(ctx); err != nil {
+		db.Close()
+		return db, err
+	}
+
+	global = db
+	return db, nil
+}
+
+func (db DB) setup(ctx context.Context) error {
+	if err := db.PingContext(ctx); err != nil {
+		return err
+	}
+	if _, err := db.ExecContext(ctx, `
+		CREATE TABLE IF NOT EXISTS data (
+			database INTEGER
+			, key TEXT
+			, value TEXT
+			, PRIMARY KEY (database, key)
+		)
+	`); err != nil {
+		return err
+	}
+	return nil
+}
+
+func Select[V any](ctx context.Context, database int, k string) (*V, error) {
+	var v V
+	err := global.Get(ctx, database, k, &v)
+	if err != nil {
+		if err != sql.ErrNoRows {
+			return nil, nil
+		}
+		return nil, err
+	}
+	return &v, nil
+}
+
+func (db DB) Get(ctx context.Context, database int, k string, vPtr any) error {
+	if err := db.get(ctx, database, k, vPtr); err != nil {
+		if err != sql.ErrNoRows {
+			return err
+		}
+	}
+	return nil
+}
+
+func (db DB) get(ctx context.Context, database int, k string, vPtr any) error {
+	row := db.QueryRowContext(ctx, `
+		SELECT value
+		FROM data
+		WHERE database=$1 AND key=$2
+	`, database, k)
+	if err := row.Err(); err != nil {
+		return err
+	}
+
+	var v string
+	if err := row.Scan(&v); err != nil {
+		return err
+	}
+
+	if err := json.Unmarshal([]byte(v), vPtr); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (db DB) Put(ctx context.Context, database int, k string, v any) error {
+	b, _ := json.Marshal(v)
+	_, err := db.ExecContext(ctx, `
+		INSERT INTO data (database, key, value)
+		VALUES ($1, $2, $3)
+
+		ON CONFLICT DO UPDATE
+
+		SET value = $3
+		WHERE database = $1 AND key = $2
+	`, database, k, string(b))
+	return err
+}
+
+func (db DB) Del(ctx context.Context, database int, k string) error {
+	_, err := db.ExecContext(ctx, `
+		DELETE FROM data
+		WHERE database=$1 AND key=$2
+	`, database, k)
+	return err
+}

src/db_test.go

@@ -0,0 +1,58 @@
+package src_test
+
+import (
+	"context"
+	"path"
+	"red-apter/src"
+	"testing"
+	"time"
+)
+
+func TestDBSqlite(t *testing.T) {
+	ctx, can := context.WithTimeout(context.Background(), time.Minute)
+	defer can()
+
+	db, err := src.NewDB(ctx, "sqlite", path.Join(t.TempDir(), "db"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(func() { db.Close() })
+
+	v := -1
+	if err := db.Get(ctx, 5, "k", &v); err != nil {
+		t.Error("failed get 404:", err)
+	} else if v != -1 {
+		t.Error("got 404:", v)
+	}
+
+	if err := db.Put(ctx, 5, "k", 6); err != nil {
+		t.Error("failed insert:", err)
+	} else if err := db.Put(ctx, 5, "k", 7); err != nil {
+		t.Error("failed update:", err)
+	}
+
+	if err := db.Get(ctx, 5, "k", &v); err != nil {
+		t.Error("failed get:", err)
+	} else if v != 7 {
+		t.Errorf("wrong get: (%T) %v but wanted 7", v, v)
+	}
+
+	if v, err := src.Select[int](ctx, 5, "k"); err != nil {
+		t.Error("failed select[int]:", err)
+	} else if v == nil || *v != 7 {
+		t.Errorf("wrong get: (%T) %v but wanted 7", v, v)
+	}
+
+	if err := db.Del(ctx, 5, "k"); err != nil {
+		t.Error("failed del:", err)
+	} else if err := db.Del(ctx, 5, "k"); err != nil {
+		t.Error("failed del 404:", err)
+	}
+
+	v = -1
+	if err := db.Get(ctx, 5, "k", &v); err != nil {
+		t.Error("failed get 410:", err)
+	} else if v != -1 {
+		t.Error("wrong get 410:", v)
+	}
+}

src/listen.go

@@ -0,0 +1,53 @@
+package src
+
+import (
+	"context"
+	"log"
+	"net"
+	"sync"
+)
+
+func listen(ctx context.Context, config Config) error {
+	wg := &sync.WaitGroup{}
+	defer wg.Wait()
+
+	listener, err := net.Listen("tcp", config.Listen)
+	if err != nil {
+		return err
+	}
+	defer listener.Close()
+
+	wg.Add(1)
+	go func() {
+		defer wg.Done()
+		<-ctx.Done()
+		listener.Close()
+	}()
+
+	for ctx.Err() == nil {
+		conn, err := listener.Accept()
+		if err != nil {
+			log.Println("error accepting:", err)
+		} else {
+			wg.Add(1)
+			go func() {
+				defer wg.Done()
+				handle(ctx, config, conn)
+			}()
+		}
+	}
+
+	return ctx.Err()
+}
+
+func handle(ctx context.Context, config Config, conn net.Conn) {
+	if err := _handle(ctx, config, conn); err != nil {
+		log.Println("error handling:", err)
+	}
+}
+
+func _handle(ctx context.Context, config Config, conn net.Conn) error {
+	defer conn.Close()
+
+	return adapt(ctx, config, conn)
+}

src/main.go

@@ -0,0 +1,19 @@
+package src
+
+import (
+	"context"
+)
+
+func Main(ctx context.Context) error {
+	config, err := NewConfig(ctx)
+	if err != nil {
+		return err
+	}
+	defer config.db.Close()
+
+	if err := listen(ctx, config); err != nil && ctx.Err() == nil {
+		return err
+	}
+
+	return nil
+}