refactoring, use context, use logger, use go mod (#24)

README.md

@@ -10,6 +10,12 @@ Look in the examples directory to learn how to use this library:
 API documentation is available at [godoc.org](https://godoc.org/github.com/go-routeros/routeros).
 Page on the [Mikrotik Wiki](http://wiki.mikrotik.com/wiki/API_in_Go).
 
-Released versions:
+Usage of `gopkg.in` was removed in favor of Go modules. Please, update you import paths to
+`github.com/go-routeros/routeros/v3`.
+
+Old released versions:
 [**v2**](https://github.com/go-routeros/routeros/tree/v2)
 [**v1**](https://github.com/go-routeros/routeros/tree/v1)
+
+To install it, run:
+`go get github.com/go-routeros/routeros/v3`

async.go

@@ -1,6 +1,10 @@
 package routeros
 
-import "github.com/go-routeros/routeros/proto"
+import (
+	"context"
+
+	"github.com/go-routeros/routeros/v3/proto"
+)
 
 type sentenceProcessor interface {
 	processSentence(sen *proto.Sentence) (bool, error)
@@ -12,6 +16,11 @@ type replyCloser interface {
 
 // Async starts asynchronous mode and returns immediately.
 func (c *Client) Async() <-chan error {
+	return c.AsyncContext(context.Background())
+}
+
+// AsyncContext starts asynchronous mode with context and returns immediately.
+func (c *Client) AsyncContext(ctx context.Context) <-chan error {
 	c.mu.Lock()
 	defer c.mu.Unlock()
 
@@ -23,16 +32,16 @@ func (c *Client) Async() <-chan error {
 	}
 	c.async = true
 	c.tags = make(map[string]sentenceProcessor)
-	go c.asyncLoopChan(errC)
+	go c.asyncLoopChan(ctx, errC)
 	return errC
 }
 
-func (c *Client) asyncLoopChan(errC chan<- error) {
+func (c *Client) asyncLoopChan(ctx context.Context, errC chan<- error) {
 	defer close(errC)
+
 	// If c.Close() has been called, c.closing will be true, and
 	// err will be “use of closed network connection”. Ignore that error.
-	err := c.asyncLoop()
-	if err != nil {
+	if err := c.asyncLoop(ctx); err != nil {
 		c.mu.Lock()
 		closing := c.closing
 		c.mu.Unlock()
@@ -42,9 +51,17 @@ func (c *Client) asyncLoopChan(errC chan<- error) {
 	}
 }
 
-func (c *Client) asyncLoop() error {
+// asyncLoop - main goroutine for async mode. Read and process sentences, handle context done.
+func (c *Client) asyncLoop(ctx context.Context) error {
+	go func() {
+		<-ctx.Done()
+
+		c.r.Cancel()
+	}()
+
 	for {
 		sen, err := c.r.ReadSentence()
+
 		if err != nil {
 			c.closeTags(err)
 			return err
@@ -53,6 +70,8 @@ func (c *Client) asyncLoop() error {
 		c.mu.Lock()
 		r, ok := c.tags[sen.Tag]
 		c.mu.Unlock()
+
+		// cannot find tag for this sentence, ignore
 		if !ok {
 			continue
 		}
@@ -71,9 +90,22 @@ func (c *Client) closeTags(err error) {
 	c.mu.Lock()
 	defer c.mu.Unlock()
 
+	// If c.Close() has been called, c.closing will be true, and
+	// err will be “use of closed network connection”. Ignore that error.
+	if c.closing {
+		for _, r := range c.tags {
+			closeReply(r, nil)
+		}
+
+		c.tags = nil
+
+		return
+	}
+
 	for _, r := range c.tags {
 		closeReply(r, err)
 	}
+
 	c.tags = nil
 }
 

chan_reply.go

@@ -1,6 +1,8 @@
 package routeros
 
-import "github.com/go-routeros/routeros/proto"
+import (
+	"github.com/go-routeros/routeros/v3/proto"
+)
 
 // chanReply is shared between ListenReply and AsyncReply.
 type chanReply struct {

client.go

@@ -4,88 +4,171 @@ Package routeros is a pure Go client library for accessing Mikrotik devices usin
 package routeros
 
 import (
-	"crypto/md5"
+	"context"
+	"crypto/md5" //nolint:gosec
 	"crypto/tls"
 	"encoding/hex"
 	"errors"
 	"fmt"
 	"io"
+	"log/slog"
 	"net"
+	"os"
 	"sync"
+	"sync/atomic"
+	"time"
 
-	"github.com/go-routeros/routeros/proto"
+	"github.com/go-routeros/routeros/v3/proto"
 )
 
 // Client is a RouterOS API client.
 type Client struct {
 	Queue int
 
+	log      *slog.Logger
+	logMutex sync.Mutex
+
 	rwc     io.ReadWriteCloser
-	r       proto.Reader
-	w       proto.Writer
 	closing bool
 	async   bool
 	nextTag int64
 	tags    map[string]sentenceProcessor
 	mu      sync.Mutex
+	mw      sync.Mutex
+
+	r proto.Reader
+	w proto.Writer
 }
 
+var (
+	ErrNoChallengeReceived      = errors.New("no ret (challenge) received")
+	ErrInvalidChallengeReceived = errors.New("invalid ret (challenge) hex string received")
+)
+
+var defaultHandler = slog.NewTextHandler(os.Stdout, &slog.HandlerOptions{
+	AddSource: true,
+	Level:     slog.LevelInfo,
+})
+
 // NewClient returns a new Client over rwc. Login must be called.
 func NewClient(rwc io.ReadWriteCloser) (*Client, error) {
 	return &Client{
 		rwc: rwc,
-		r:   proto.NewReader(rwc),
-		w:   proto.NewWriter(rwc),
+		log: slog.New(defaultHandler),
+
+		r: proto.NewReader(rwc),
+		w: proto.NewWriter(rwc),
 	}, nil
 }
 
+// incrementTag atomically increments tag number and returns result
+func (c *Client) incrementTag() int64 {
+	return atomic.AddInt64(&c.nextTag, 1)
+}
+
+// IsAsync return true if client run in async mode.
+func (c *Client) IsAsync() bool {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+
+	return c.async
+}
+
 // Dial connects and logs in to a RouterOS device.
 func Dial(address, username, password string) (*Client, error) {
-	conn, err := net.Dial("tcp", address)
+	return DialContext(context.Background(), address, username, password)
+}
+
+// DialTimeout connects and logs in to a RouterOS device with timeout.
+func DialTimeout(address, username, password string, timeout time.Duration) (*Client, error) {
+	ctx, cancel := context.WithTimeout(context.Background(), timeout)
+	defer cancel()
+
+	return DialContext(ctx, address, username, password)
+}
+
+// DialContext connects and logs in to a RouterOS device using context.
+func DialContext(ctx context.Context, address, username, password string) (*Client, error) {
+	conn, err := new(net.Dialer).DialContext(ctx, "tcp", address)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("could not connect to router os: %w", err)
 	}
-	return newClientAndLogin(conn, username, password)
+	return newClientAndLogin(ctx, conn, username, password)
 }
 
 // DialTLS connects and logs in to a RouterOS device using TLS.
 func DialTLS(address, username, password string, tlsConfig *tls.Config) (*Client, error) {
-	conn, err := tls.Dial("tcp", address, tlsConfig)
+	return DialTLSContext(context.Background(), address, username, password, tlsConfig)
+}
+
+// DialTLSTimeout connects and logs in to a RouterOS device using TLS with timeout.
+func DialTLSTimeout(address, username, password string, tlsConfig *tls.Config, timeout time.Duration) (*Client, error) {
+	ctx, cancel := context.WithTimeout(context.Background(), timeout)
+	defer cancel()
+
+	return DialTLSContext(ctx, address, username, password, tlsConfig)
+}
+
+// DialTLSContext connects and logs in to a RouterOS device using TLS and context.
+func DialTLSContext(ctx context.Context, address, username, password string, tlsConfig *tls.Config) (*Client, error) {
+	conn, err := (&tls.Dialer{Config: tlsConfig}).DialContext(ctx, "tcp", address)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("could not connect to router os: %w", err)
 	}
-	return newClientAndLogin(conn, username, password)
+	return newClientAndLogin(ctx, conn, username, password)
 }
 
-func newClientAndLogin(rwc io.ReadWriteCloser, username, password string) (*Client, error) {
+// newClientAndLogin - creates a new client with context over specified rwc, then logs in to the RouterOS, returns new client.
+func newClientAndLogin(ctx context.Context, rwc io.ReadWriteCloser, username, password string) (*Client, error) {
 	c, err := NewClient(rwc)
 	if err != nil {
-		rwc.Close()
-		return nil, err
+		return nil, fmt.Errorf("could not connect to router os: %w; close: %w", err, rwc.Close())
 	}
-	err = c.Login(username, password)
+	err = c.LoginContext(ctx, username, password)
 	if err != nil {
-		c.Close()
-		return nil, err
+		return nil, fmt.Errorf("could not login: %w; close %w", err, c.Close())
 	}
 	return c, nil
 }
 
+func (c *Client) SetLogHandler(handler LogHandler) {
+	c.logMutex.Lock()
+	c.log = slog.New(handler)
+	c.logMutex.Unlock()
+}
+
+func (c *Client) logger() *slog.Logger {
+	c.logMutex.Lock()
+	defer c.logMutex.Unlock()
+
+	return c.log
+}
+
 // Close closes the connection to the RouterOS device.
-func (c *Client) Close() {
+func (c *Client) Close() error {
 	c.mu.Lock()
+	defer c.mu.Unlock()
+
+	c.r.Close()
+	c.w.Close()
+
 	if c.closing {
-		c.mu.Unlock()
-		return
+		return nil
 	}
+
 	c.closing = true
-	c.mu.Unlock()
-	c.rwc.Close()
+
+	return c.rwc.Close()
 }
 
 // Login runs the /login command. Dial and DialTLS call this automatically.
 func (c *Client) Login(username, password string) error {
-	r, err := c.Run("/login", "=name="+username, "=password="+password)
+	return c.LoginContext(context.Background(), username, password)
+}
+
+// LoginContext runs the /login command. DialContext and DialTLSContext call this automatically.
+func (c *Client) LoginContext(ctx context.Context, username, password string) error {
+	r, err := c.RunContext(ctx, "/login", "=name="+username, "=password="+password)
 	if err != nil {
 		return err
 	}
@@ -95,27 +178,25 @@ func (c *Client) Login(username, password string) error {
 		if r.Done != nil {
 			return nil
 		}
-		return errors.New("RouterOS: /login: no ret (challenge) received")
+		return fmt.Errorf("RouterOS: /login: %w", ErrNoChallengeReceived)
 	}
 
 	// Login method pre-6.43 two stages, challenge
-	b, err := hex.DecodeString(ret)
-	if err != nil {
-		return fmt.Errorf("RouterOS: /login: invalid ret (challenge) hex string received: %s", err)
+	var dec []byte
+	if dec, err = hex.DecodeString(ret); err != nil {
+		return fmt.Errorf("RouterOS: /login: %w: %w", ErrInvalidChallengeReceived, err)
 	}
 
-	r, err = c.Run("/login", "=name="+username, "=response="+c.challengeResponse(b, password))
-	if err != nil {
-		return err
-	}
+	_, err = c.RunContext(ctx, "/login", "=name="+username, "=response="+c.challengeResponse(dec, password))
 
-	return nil
+	return err
 }
 
+// challengeResponse - prepare MD5 hash for auth challenge response
 func (c *Client) challengeResponse(cha []byte, password string) string {
-	h := md5.New()
+	h := md5.New() //nolint:gosec
 	h.Write([]byte{0})
-	io.WriteString(h, password)
+	h.Write([]byte(password))
 	h.Write(cha)
 	return fmt.Sprintf("00%x", h.Sum(nil))
 }