add live reloading support for bypass,resolver and hosts

bypass.go

 package gost
 
 import (
+	"bufio"
 	"bytes"
 	"fmt"
+	"io"
 	"net"
 	"strconv"
 	"strings"
+	"sync"
+	"time"
 
 	glob "github.com/gobwas/glob"
 )
@@ -118,28 +122,30 @@ func (m *domainMatcher) String() string {
 // It contains a list of matchers.
 type Bypass struct {
 	matchers []Matcher
-	reverse  bool
+	reversed bool
+	period   time.Duration // the period for live reloading
+	mux      sync.Mutex
 }
 
 // NewBypass creates and initializes a new Bypass using matchers as its match rules.
 // The rules will be reversed if the reversed is true.
-func NewBypass(matchers []Matcher, reverse bool) *Bypass {
+func NewBypass(reversed bool, matchers ...Matcher) *Bypass {
 	return &Bypass{
 		matchers: matchers,
-		reverse:  reverse,
+		reversed: reversed,
 	}
 }
 
 // NewBypassPatterns creates and initializes a new Bypass using matcher patterns as its match rules.
 // The rules will be reversed if the reverse is true.
-func NewBypassPatterns(patterns []string, reverse bool) *Bypass {
+func NewBypassPatterns(reversed bool, patterns ...string) *Bypass {
 	var matchers []Matcher
 	for _, pattern := range patterns {
 		if pattern != "" {
 			matchers = append(matchers, NewMatcher(pattern))
 		}
 	}
-	return NewBypass(matchers, reverse)
+	return NewBypass(reversed, matchers...)
 }
 
 // Contains reports whether the bypass includes addr.
@@ -153,6 +159,10 @@ func (bp *Bypass) Contains(addr string) bool {
 			addr = host
 		}
 	}
+
+	bp.mux.Lock()
+	defer bp.mux.Unlock()
+
 	var matched bool
 	for _, matcher := range bp.matchers {
 		if matcher == nil {
@@ -163,8 +173,8 @@ func (bp *Bypass) Contains(addr string) bool {
 			break
 		}
 	}
-	return !bp.reverse && matched ||
-		bp.reverse && !matched
+	return !bp.reversed && matched ||
+		bp.reversed && !matched
 }
 
 // AddMatchers appends matchers to the bypass matcher list.
@@ -179,7 +189,71 @@ func (bp *Bypass) Matchers() []Matcher {
 
 // Reversed reports whether the rules of the bypass are reversed.
 func (bp *Bypass) Reversed() bool {
-	return bp.reverse
+	return bp.reversed
+}
+
+// Reload parses config from r, then live reloads the bypass.
+func (bp *Bypass) Reload(r io.Reader) error {
+	var matchers []Matcher
+
+	scanner := bufio.NewScanner(r)
+	for scanner.Scan() {
+		line := scanner.Text()
+		if n := strings.IndexByte(line, '#'); n >= 0 {
+			line = line[:n]
+		}
+		line = strings.Replace(line, "\t", " ", -1)
+		line = strings.TrimSpace(line)
+		if line == "" {
+			continue
+		}
+
+		// reload option
+		if strings.HasPrefix(line, "reload ") {
+			var ss []string
+			for _, s := range strings.Split(line, " ") {
+				if s = strings.TrimSpace(s); s != "" {
+					ss = append(ss, s)
+				}
+			}
+			if len(ss) == 2 {
+				bp.period, _ = time.ParseDuration(ss[1])
+				continue
+			}
+		}
+
+		// reverse option
+		if strings.HasPrefix(line, "reverse ") {
+			var ss []string
+			for _, s := range strings.Split(line, " ") {
+				if s = strings.TrimSpace(s); s != "" {
+					ss = append(ss, s)
+				}
+			}
+			if len(ss) == 2 {
+				bp.reversed, _ = strconv.ParseBool(ss[1])
+				continue
+			}
+		}
+
+		matchers = append(matchers, NewMatcher(line))
+	}
+
+	if err := scanner.Err(); err != nil {
+		return err
+	}
+
+	bp.mux.Lock()
+	defer bp.mux.Unlock()
+
+	bp.matchers = matchers
+
+	return nil
+}
+
+// Period returns the reload period
+func (bp *Bypass) Period() time.Duration {
+	return bp.period
 }
 
 func (bp *Bypass) String() string {

cmd/gost/bypass.txt

+# period for live reloading
+reload      10s
+
+# matcher reversed
+ reverse     true
+
 10.0.0.1
 192.168.0.0/24
 172.1.0.0/16
 192.168.100.190/32
-*.example.com
+*.example.com
\ No newline at end of file
+.example.org
\ No newline at end of file

cmd/gost/cfg.go

@@ -10,7 +10,6 @@ import (
 	"io/ioutil"
 	"net/url"
 	"os"
-	"strconv"
 	"strings"
 	"time"
 
@@ -243,22 +242,14 @@ func parseBypass(s string) *gost.Bypass {
 			}
 			matchers = append(matchers, gost.NewMatcher(s))
 		}
-		return gost.NewBypass(matchers, reversed)
+		return gost.NewBypass(reversed, matchers...)
 	}
+	f.Close()
 
-	scanner := bufio.NewScanner(f)
-	for scanner.Scan() {
-		line := scanner.Text()
-		if n := strings.IndexByte(line, '#'); n >= 0 {
-			line = line[:n]
-		}
-		line = strings.TrimSpace(line)
-		if line == "" {
-			continue
-		}
-		matchers = append(matchers, gost.NewMatcher(line))
-	}
-	return gost.NewBypass(matchers, reversed)
+	bp := gost.NewBypass(reversed)
+	go gost.PeriodReload(bp, s)
+
+	return bp
 }
 
 func parseResolver(cfg string) gost.Resolver {
@@ -289,59 +280,12 @@ func parseResolver(cfg string) gost.Resolver {
 				})
 			}
 		}
-		return gost.NewResolver(nss, timeout, ttl)
+		return gost.NewResolver(timeout, ttl, nss...)
 	}
+	f.Close()
 
-	scanner := bufio.NewScanner(f)
-	for scanner.Scan() {
-		line := scanner.Text()
-		if n := strings.IndexByte(line, '#'); n >= 0 {
-			line = line[:n]
-		}
-		line = strings.TrimSpace(line)
-		if line == "" {
-			continue
-		}
-		var ss []string
-		for _, s := range strings.Split(line, " ") {
-			if s = strings.TrimSpace(s); s != "" {
-				ss = append(ss, s)
-			}
-		}
+	resolver := gost.NewResolver(timeout, ttl)
+	go gost.PeriodReload(resolver, cfg)
 
-		if len(ss) == 0 {
-			continue
-		}
-
-		if strings.ToLower(ss[0]) == "timeout" {
-			if len(ss) >= 2 {
-				if n, _ := strconv.Atoi(ss[1]); n > 0 {
-					timeout = time.Second * time.Duration(n)
-				}
-			}
-			continue
-		}
-		if strings.ToLower(ss[0]) == "ttl" {
-			if len(ss) >= 2 {
-				n, _ := strconv.Atoi(ss[1])
-				ttl = time.Second * time.Duration(n)
-			}
-			continue
-		}
-
-		var ns gost.NameServer
-		switch len(ss) {
-		case 1:
-			ns.Addr = ss[0]
-		case 2:
-			ns.Addr = ss[0]
-			ns.Protocol = ss[1]
-		default:
-			ns.Addr = ss[0]
-			ns.Protocol = ss[1]
-			ns.Hostname = ss[2]
-		}
-		nss = append(nss, ns)
-	}
-	return gost.NewResolver(nss, timeout, ttl)
+	return resolver
 }

cmd/gost/dns.txt

 # resolver timeout, default 30s.
-timeout     10
+timeout     10s
 
 # resolver cache TTL, default 60s, minus value means that cache is disabled.
-ttl         300
+ttl         300s
+
+# period for live reloading
+reload      10s
 
 # ip[:port]  [protocol]  [hostname]
 

cmd/gost/hosts.txt

+# period for live reloading
+reload      10s
+
 # The following lines are desirable for IPv4 capable hosts
 127.0.0.1       localhost
 
@@ -11,4 +14,4 @@
 # The following lines are desirable for IPv6 capable hosts
 ::1             localhost ip6-localhost ip6-loopback
 ff02::1         ip6-allnodes
-ff02::2         ip6-allrouters
+ff02::2         ip6-allrouters
\ No newline at end of file

cmd/gost/main.go

@@ -153,7 +153,7 @@ func (r *route) initChain() (*gost.Chain, error) {
 		var bypass *gost.Bypass
 		// global bypass
 		if peerCfg.Bypass != nil {
-			bypass = gost.NewBypassPatterns(peerCfg.Bypass.Patterns, peerCfg.Bypass.Reverse)
+			bypass = gost.NewBypassPatterns(peerCfg.Bypass.Reverse, peerCfg.Bypass.Patterns...)
 		}
 		nodes = ngroup.Nodes()
 		for i := range nodes {
@@ -492,10 +492,9 @@ func (r *route) serve() error {
 
 		var hosts *gost.Hosts
 		if f, _ := os.Open(node.Get("hosts")); f != nil {
-			hosts, err = gost.ParseHosts(f)
-			if err != nil {
-				log.Logf("[hosts] %s: %v", f.Name(), err)
-			}
+			f.Close()
+			hosts = gost.NewHosts()
+			go gost.PeriodReload(hosts, node.Get("hosts"))
 		}
 
 		handler.Init(

hosts.go

@@ -5,6 +5,7 @@ import (
 	"io"
 	"net"
 	"strings"
+	"time"
 
 	"github.com/go-log/log"
 )
@@ -17,8 +18,13 @@ type Host struct {
 }
 
 // Hosts is a static table lookup for hostnames.
+// For each host a single line should be present with the following information:
+// IP_address canonical_hostname [aliases...]
+// Fields of the entry are separated by any number of blanks and/or tab characters.
+// Text from a "#" character until the end of the line is a comment, and is ignored.
 type Hosts struct {
-	hosts []Host
+	hosts  []Host
+	period time.Duration
 }
 
 // NewHosts creates a Hosts with optional list of host
@@ -28,13 +34,38 @@ func NewHosts(hosts ...Host) *Hosts {
 	}
 }
 
-// ParseHosts parses host table from r.
-// For each host a single line should be present with the following information:
-// IP_address canonical_hostname [aliases...]
-// Fields of the entry are separated by any number of blanks and/or tab characters.
-// Text from a "#" character until the end of the line is a comment, and is ignored.
-func ParseHosts(r io.Reader) (*Hosts, error) {
-	hosts := NewHosts()
+// AddHost adds host(s) to the host table.
+func (h *Hosts) AddHost(host ...Host) {
+	h.hosts = append(h.hosts, host...)
+}
+
+// Lookup searches the IP address corresponds to the given host from the host table.
+func (h *Hosts) Lookup(host string) (ip net.IP) {
+	if h == nil {
+		return
+	}
+	for _, h := range h.hosts {
+		if h.Hostname == host {
+			ip = h.IP
+			break
+		}
+		for _, alias := range h.Aliases {
+			if alias == host {
+				ip = h.IP
+				break
+			}
+		}
+	}
+	if ip != nil && Debug {
+		log.Logf("[hosts] hit: %s %s", host, ip.String())
+	}
+	return
+}
+
+// Reload parses config from r, then live reloads the hosts.
+func (h *Hosts) Reload(r io.Reader) error {
+	var hosts []Host
+
 	scanner := bufio.NewScanner(r)
 	for scanner.Scan() {
 		line := scanner.Text()
@@ -55,6 +86,13 @@ func ParseHosts(r io.Reader) (*Hosts, error) {
 		if len(ss) < 2 {
 			continue // invalid lines are ignored
 		}
+
+		// reload option
+		if strings.ToLower(ss[0]) == "reload" {
+			h.period, _ = time.ParseDuration(ss[1])
+			continue
+		}
+
 		ip := net.ParseIP(ss[0])
 		if ip == nil {
 			continue // invalid IP addresses are ignored
@@ -66,39 +104,17 @@ func ParseHosts(r io.Reader) (*Hosts, error) {
 		if len(ss) > 2 {
 			host.Aliases = ss[2:]
 		}
-		hosts.AddHost(host)
+		hosts = append(hosts, host)
 	}
 	if err := scanner.Err(); err != nil {
-		return nil, err
+		return err
 	}
 
-	return hosts, nil
+	h.hosts = hosts
+	return nil
 }
 
-// AddHost adds host(s) to the host table.
-func (h *Hosts) AddHost(host ...Host) {
-	h.hosts = append(h.hosts, host...)
-}
-
-// Lookup searches the IP address corresponds to the given host from the host table.
-func (h *Hosts) Lookup(host string) (ip net.IP) {
-	if h == nil {
-		return
-	}
-	for _, h := range h.hosts {
-		if h.Hostname == host {
-			ip = h.IP
-			break
-		}
-		for _, alias := range h.Aliases {
-			if alias == host {
-				ip = h.IP
-				break
-			}
-		}
-	}
-	if ip != nil && Debug {
-		log.Logf("[hosts] hit: %s %s", host, ip.String())
-	}
-	return
+// Period returns the reload period
+func (h *Hosts) Period() time.Duration {
+	return h.period
 }

reload.go

+package gost
+
+import (
+	"io"
+	"os"
+	"time"
+
+	"github.com/go-log/log"
+)
+
+// Reloader is the interface for objects that support live reloading.
+type Reloader interface {
+	Reload(r io.Reader) error
+	Period() time.Duration
+}
+
+// PeriodReload reloads the config periodically according to the period of the reloader.
+func PeriodReload(r Reloader, configFile string) error {
+	var lastMod time.Time
+
+	for {
+		f, err := os.Open(configFile)
+		if err != nil {
+			return err
+		}
+
+		finfo, err := f.Stat()
+		if err != nil {
+			return err
+		}
+		mt := finfo.ModTime()
+		if !mt.Equal(lastMod) {
+			if Debug {
+				log.Log("[reload]", configFile)
+			}
+			r.Reload(f)
+			lastMod = mt
+		}
+		f.Close()
+
+		period := r.Period()
+		if period <= 0 {
+			log.Log("[reload] disabled:", configFile)
+			return nil
+		}
+		if period < time.Second {
+			period = time.Second
+		}
+
+		<-time.After(period)
+	}
+}

resolver.go

 package gost
 
 import (
+	"bufio"
 	"bytes"
 	"context"
 	"crypto/tls"
 	"fmt"
+	"io"
 	"net"
 	"strings"
 	"sync"
@@ -27,6 +29,12 @@ type Resolver interface {
 	Resolve(host string) ([]net.IP, error)
 }
 
+// ReloadResolver is resolover that support live reloading
+type ReloadResolver interface {
+	Resolver
+	Reloader
+}
+
 // NameServer is a name server.
 // Currently supported protocol: TCP, UDP and TLS.
 type NameServer struct {
@@ -56,13 +64,14 @@ type resolverCacheItem struct {
 type resolver struct {
 	Resolver *net.Resolver
 	Servers  []NameServer
+	mCache   *sync.Map
 	Timeout  time.Duration
 	TTL      time.Duration
-	mCache   *sync.Map
+	period   time.Duration
 }
 
 // NewResolver create a new Resolver with the given name servers and resolution timeout.
-func NewResolver(servers []NameServer, timeout, ttl time.Duration) Resolver {
+func NewResolver(timeout, ttl time.Duration, servers ...NameServer) ReloadResolver {
 	r := &resolver{
 		Servers: servers,
 		Timeout: timeout,
@@ -184,6 +193,77 @@ func (r *resolver) storeCache(name string, ips []net.IP) {
 	})
 }
 
+func (r *resolver) Reload(rd io.Reader) error {
+	var nss []NameServer
+
+	scanner := bufio.NewScanner(rd)
+	for scanner.Scan() {
+		line := scanner.Text()
+		if n := strings.IndexByte(line, '#'); n >= 0 {
+			line = line[:n]
+		}
+		line = strings.Replace(line, "\t", " ", -1)
+		line = strings.TrimSpace(line)
+		if line == "" {
+			continue
+		}
+		var ss []string
+		for _, s := range strings.Split(line, " ") {
+			if s = strings.TrimSpace(s); s != "" {
+				ss = append(ss, s)
+			}
+		}
+
+		if len(ss) == 0 {
+			continue
+		}
+
+		if len(ss) >= 2 {
+			// timeout option
+			if strings.ToLower(ss[0]) == "timeout" {
+				r.Timeout, _ = time.ParseDuration(ss[1])
+				continue
+			}
+
+			// ttl option
+			if strings.ToLower(ss[0]) == "ttl" {
+				r.TTL, _ = time.ParseDuration(ss[1])
+				continue
+			}
+
+			// reload option
+			if strings.ToLower(ss[0]) == "reload" {
+				r.period, _ = time.ParseDuration(ss[1])
+				continue
+			}
+		}
+
+		var ns NameServer
+		switch len(ss) {
+		case 1:
+			ns.Addr = ss[0]
+		case 2:
+			ns.Addr = ss[0]
+			ns.Protocol = ss[1]
+		default:
+			ns.Addr = ss[0]
+			ns.Protocol = ss[1]
+			ns.Hostname = ss[2]
+		}
+		nss = append(nss, ns)
+	}
+	if err := scanner.Err(); err != nil {
+		return err
+	}
+
+	r.Servers = nss
+	return nil
+}
+
+func (r *resolver) Period() time.Duration {
+	return r.period
+}
+
 func (r *resolver) String() string {
 	if r == nil {
 		return ""
@@ -192,6 +272,7 @@ func (r *resolver) String() string {
 	b := &bytes.Buffer{}
 	fmt.Fprintf(b, "Timeout %v\n", r.Timeout)
 	fmt.Fprintf(b, "TTL %v\n", r.TTL)
+	fmt.Fprintf(b, "Reload %v\n", r.period)
 	for i := range r.Servers {
 		fmt.Fprintln(b, r.Servers[i])
 	}