SWAPDB

Author: Harmen

.gitignore

@@ -1 +1,2 @@
 /integration/redis_src/
+*.swp

README.md

@@ -74,7 +74,7 @@ This should be the change needed to upgrade:
 1.0:
 
     m.Expire() == 4
-   
+
 2.0:
 
     m.TTL() == 4 * time.Second
@@ -92,7 +92,7 @@ Implemented commands:
    - PING
    - SELECT
    - QUIT
- - Key 
+ - Key
    - DEL
    - EXISTS
    - EXPIRE
@@ -328,13 +328,13 @@ Commands which will probably not be implemented:
     - ~~SLAVEOF~~
     - ~~SLOWLOG~~
     - ~~SYNC~~
-    
+
 
 ## &c.
 
 Tests are run against Redis 5.0.3. The [./integration](./integration/) subdir
 compares miniredis against a real redis instance.
 
 
-[![Build Status](https://travis-ci.org/alicebob/miniredis.svg?branch=master)](https://travis-ci.org/alicebob/miniredis) 
+[![Build Status](https://travis-ci.org/alicebob/miniredis.svg?branch=master)](https://travis-ci.org/alicebob/miniredis)
 [![GoDoc](https://godoc.org/github.com/alicebob/miniredis?status.svg)](https://godoc.org/github.com/alicebob/miniredis)

cmd_connection.go

@@ -13,6 +13,7 @@ func commandsConnection(m *Miniredis) {
 	m.srv.Register("ECHO", m.cmdEcho)
 	m.srv.Register("PING", m.cmdPing)
 	m.srv.Register("SELECT", m.cmdSelect)
+	m.srv.Register("SWAPDB", m.cmdSwapdb)
 	m.srv.Register("QUIT", m.cmdQuit)
 }
 
@@ -124,6 +125,42 @@ func (m *Miniredis) cmdSelect(c *server.Peer, cmd string, args []string) {
 	c.WriteOK()
 }
 
+// SWAPDB
+func (m *Miniredis) cmdSwapdb(c *server.Peer, cmd string, args []string) {
+	if len(args) != 2 {
+		setDirty(c)
+		c.WriteError(errWrongNumber(cmd))
+		return
+	}
+	if !m.handleAuth(c) {
+		return
+	}
+
+	withTx(m, c, func(c *server.Peer, ctx *connCtx) {
+		id1, err := strconv.Atoi(args[0])
+		if err != nil {
+			c.WriteError("ERR invalid first DB index")
+			setDirty(c)
+			return
+		}
+		id2, err := strconv.Atoi(args[1])
+		if err != nil {
+			c.WriteError("ERR invalid second DB index")
+			setDirty(c)
+			return
+		}
+		if id1 < 0 || id2 < 0 {
+			c.WriteError("ERR DB index is out of range")
+			setDirty(c)
+			return
+		}
+
+		m.swapDB(id1, id2)
+
+		c.WriteOK()
+	})
+}
+
 // QUIT
 func (m *Miniredis) cmdQuit(c *server.Peer, cmd string, args []string) {
 	// QUIT isn't transactionfied and accepts any arguments.

cmd_connection_test.go

@@ -95,6 +95,66 @@ func TestSelect(t *testing.T) {
 	equals(t, "bar", v)
 }
 
+func TestSwapdb(t *testing.T) {
+	s, err := Run()
+	ok(t, err)
+	defer s.Close()
+	c, err := redis.Dial("tcp", s.Addr())
+	ok(t, err)
+
+	_, err = redis.String(c.Do("SET", "foo", "bar"))
+	ok(t, err)
+
+	_, err = redis.String(c.Do("SELECT", "5"))
+	ok(t, err)
+
+	_, err = redis.String(c.Do("SET", "foo", "baz"))
+	ok(t, err)
+
+	res, err := redis.String(c.Do("SWAPDB", "0", "5"))
+	ok(t, err)
+	equals(t, "OK", res)
+
+	got, err := s.Get("foo")
+	ok(t, err)
+	equals(t, "baz", got)
+	s.Select(5)
+	got, err = s.Get("foo")
+	ok(t, err)
+	equals(t, "bar", got)
+
+	// Another connection should have its own idea of the db:
+	c2, err := redis.Dial("tcp", s.Addr())
+	ok(t, err)
+	v, err := redis.String(c2.Do("GET", "foo"))
+	ok(t, err)
+	equals(t, "baz", v)
+
+	// errors
+	{
+		_, err := redis.String(c.Do("SWAPDB"))
+		mustFail(t, err, errWrongNumber("SWAPDB"))
+
+		_, err = redis.String(c.Do("SWAPDB", 1, 2, 3))
+		mustFail(t, err, errWrongNumber("SWAPDB"))
+
+		_, err = redis.String(c.Do("SWAPDB", "foo", 2))
+		mustFail(t, err, "ERR invalid first DB index")
+
+		_, err = redis.String(c.Do("SWAPDB", 1, "bar"))
+		mustFail(t, err, "ERR invalid second DB index")
+
+		_, err = redis.String(c.Do("SWAPDB", "foo", "bar"))
+		mustFail(t, err, "ERR invalid first DB index")
+
+		_, err = redis.String(c.Do("SWAPDB", -1, 2))
+		mustFail(t, err, "ERR DB index is out of range")
+
+		_, err = redis.String(c.Do("SWAPDB", 1, -2))
+		mustFail(t, err, "ERR DB index is out of range")
+	}
+}
+
 func TestQuit(t *testing.T) {
 	s, err := Run()
 	ok(t, err)

cmd_scripting.go

@@ -9,7 +9,7 @@ import (
 	"strings"
 
 	luajson "github.com/alicebob/gopher-json"
-	"github.com/yuin/gopher-lua"
+	lua "github.com/yuin/gopher-lua"
 	"github.com/yuin/gopher-lua/parse"
 
 	"github.com/alicebob/miniredis/server"

integration/generic_test.go

@@ -213,3 +213,39 @@ func TestProto(t *testing.T) {
 		succ("ECHO", strings.Repeat("X", 1<<24)),
 	)
 }
+
+func TestSwapdb(t *testing.T) {
+	testCommands(t,
+		succ("SET", "key1", "val1"),
+		succ("SWAPDB", "0", "1"),
+		succ("SELECT", "1"),
+		succ("GET", "key1"),
+
+		succ("SWAPDB", "1", "1"),
+		succ("GET", "key1"),
+
+		fail("SWAPDB"),
+		fail("SWAPDB", 1),
+		fail("SWAPDB", 1, 2, 3),
+		fail("SWAPDB", "foo", 2),
+		fail("SWAPDB", 1, "bar"),
+		fail("SWAPDB", "foo", "bar"),
+		fail("SWAPDB", -1, 2),
+		fail("SWAPDB", 1, -2),
+		// fail("SWAPDB", 1, 1000), // miniredis has no upperlimit
+	)
+
+	// SWAPDB with transactions
+	testClients2(t, func(r1, r2 chan<- command) {
+		r1 <- succ("SET", "foo", "foooooo")
+
+		r1 <- succ("MULTI")
+		r1 <- succ("SWAPDB", 0, 2)
+		r1 <- succ("GET", "foo")
+		r2 <- succ("GET", "foo")
+
+		r1 <- succ("EXEC")
+		r1 <- succ("GET", "foo")
+		r2 <- succ("GET", "foo")
+	})
+}

lua.go

@@ -2,7 +2,7 @@ package miniredis
 
 import (
 	redigo "github.com/gomodule/redigo/redis"
-	"github.com/yuin/gopher-lua"
+	lua "github.com/yuin/gopher-lua"
 
 	"github.com/alicebob/miniredis/server"
 )

miniredis.go

@@ -197,6 +197,27 @@ func (m *Miniredis) db(i int) *RedisDB {
 	return &db
 }
 
+// SwapDB swaps DBs by IDs.
+func (m *Miniredis) SwapDB(i, j int) bool {
+	m.Lock()
+	defer m.Unlock()
+	return m.swapDB(i, j)
+}
+
+// swap DB. No locks!
+func (m *Miniredis) swapDB(i, j int) bool {
+	db1 := m.db(i)
+	db2 := m.db(j)
+
+	db1.id = j
+	db2.id = i
+
+	m.dbs[i] = db2
+	m.dbs[j] = db1
+
+	return true
+}
+
 // Addr returns '127.0.0.1:12345'. Can be given to a Dial(). See also Host()
 // and Port(), which return the same things.
 func (m *Miniredis) Addr() string {