add logging

README.md

@@ -2,6 +2,5 @@
 
 TODO:
 
-+ Decent Logging;
 + README Documentation;
 + Unit-Tests;

cmd/exip/main.go

@@ -3,6 +3,7 @@ package main
 import (
 	"flag"
 	"fmt"
+	"log"
 	"os"
 	"time"
 
@@ -11,8 +12,8 @@ import (
 
 // CLI Flags
 var (
-	timeout = flag.Duration("t", time.Second*2, "consensus's voting timeout")
-	verbose = flag.Bool("v", false, "verbose logging")
+	timeout = flag.Duration("t", time.Second*5, "consensus's voting timeout")
+	verbose = flag.Bool("v", false, "log errors to STDERR, when defined")
 )
 
 func main() {
@@ -22,11 +23,15 @@ func main() {
 		cfg.WithTimeout(*timeout)
 	}
 
-	// TODO: Add Logging (and use the verbose flag)
+	// optionally create the logger,
+	// if no logger is defined, all logs will be discarded.
+	var logger *log.Logger
+	if verbose != nil && *verbose {
+		logger = externalip.NewLogger(os.Stderr)
+	}
 
 	// create the consensus
-	consensus := externalip.DefaultConsensus(
-		externalip.DefaultConsensusConfig().WithTimeout(*timeout))
+	consensus := externalip.DefaultConsensus(cfg, logger)
 
 	// retrieve the external ip
 	ip, err := consensus.ExternalIP()

consensus.go

@@ -1,7 +1,7 @@
 package externalip
 
 import (
-	"fmt"
+	"log"
 	"net"
 	"sync"
 	"time"
@@ -20,8 +20,8 @@ func DefaultConsensusConfig() *ConsensusConfig {
 // with default and recommended HTTPSources.
 // TLS-Protected providers get more power,
 // compared to plain-text providers.
-func DefaultConsensus(cfg *ConsensusConfig) *Consensus {
-	consensus := NewConsensus(cfg)
+func DefaultConsensus(cfg *ConsensusConfig, logger *log.Logger) *Consensus {
+	consensus := NewConsensus(cfg, logger)
 
 	// TLS-protected providers
 	consensus.AddVoter(NewHTTPSource("https://icanhazip.com/"), 3)
@@ -34,7 +34,6 @@ func DefaultConsensus(cfg *ConsensusConfig) *Consensus {
 	consensus.AddVoter(NewHTTPSource("http://whatismyip.akamai.com/"), 1)
 	consensus.AddVoter(NewHTTPSource("http://tnx.nl/ip"), 1)
 	consensus.AddVoter(NewHTTPSource("http://myip.dnsomatic.com/"), 1)
-	consensus.AddVoter(NewHTTPSource("http://ipecho.net/plain"), 1)
 	consensus.AddVoter(NewHTTPSource("http://diagnostic.opendns.com/myip"), 1)
 
 	return consensus
@@ -42,12 +41,16 @@ func DefaultConsensus(cfg *ConsensusConfig) *Consensus {
 
 // NewConsensus creates a new Consensus, with no sources.
 // When the given cfg is <nil>, the `DefaultConsensusConfig` will be used.
-func NewConsensus(cfg *ConsensusConfig) *Consensus {
+func NewConsensus(cfg *ConsensusConfig, logger *log.Logger) *Consensus {
 	if cfg == nil {
 		cfg = DefaultConsensusConfig()
 	}
+	if logger == nil {
+		logger = NewLogger(nil)
+	}
 	return &Consensus{
 		timeout: cfg.Timeout,
+		logger:  logger,
 	}
 }
 
@@ -70,6 +73,7 @@ func (cfg *ConsensusConfig) WithTimeout(timeout time.Duration) *ConsensusConfig
 type Consensus struct {
 	voters  []voter
 	timeout time.Duration
+	logger  *log.Logger
 }
 
 // AddVoter adds a voter to this consensus.
@@ -103,7 +107,7 @@ func (c *Consensus) ExternalIP() (net.IP, error) {
 		wg.Add(1)
 		go func(v voter) {
 			defer wg.Done()
-			ip, err := v.source.IP(c.timeout)
+			ip, err := v.source.IP(c.timeout, c.logger)
 			if err == nil && ip != nil {
 				vlock.Lock()
 				defer vlock.Unlock()
@@ -116,9 +120,6 @@ func (c *Consensus) ExternalIP() (net.IP, error) {
 	// or until the voting process times out
 	select {
 	case <-waitWG(&wg):
-		fmt.Println("done!") // TODO: Log instead
-	case <-time.After(c.timeout):
-		fmt.Println("timeout!") // TODO: Log instead
 	}
 
 	// if no votes were casted succesfully,

log.go

@@ -0,0 +1,18 @@
+package externalip
+
+import (
+	"io"
+	"io/ioutil"
+	"log"
+)
+
+// NewLogger returns a new standard logger, with a given writer.
+// if w is <nil>, all logs will be discarded.
+func NewLogger(w io.Writer) *log.Logger {
+	if w == nil {
+		w = ioutil.Discard
+	}
+
+	return log.New(w, "",
+		log.Ldate|log.Ltime|log.Lmicroseconds|log.Llongfile|log.Lshortfile)
+}

sources.go

@@ -2,6 +2,7 @@ package externalip
 
 import (
 	"io/ioutil"
+	"log"
 	"net"
 	"net/http"
 	"strings"
@@ -37,11 +38,12 @@ func (s *HTTPSource) WithParser(parser ContentParser) *HTTPSource {
 }
 
 // IP implements Source.IP
-func (s *HTTPSource) IP(timeout time.Duration) (net.IP, error) {
+func (s *HTTPSource) IP(timeout time.Duration, logger *log.Logger) (net.IP, error) {
 	// Define the GET method with the correct url,
 	// setting the User-Agent to our library
 	req, err := http.NewRequest("GET", s.url, nil)
 	if err != nil {
+		logger.Printf("[ERROR] could not create a GET Request for %q: %v\n", s.url, err)
 		return nil, err
 	}
 	req.Header.Set("User-Agent", "go-external-ip (github.com/glendc/go-external-ip)")
@@ -50,12 +52,14 @@ func (s *HTTPSource) IP(timeout time.Duration) (net.IP, error) {
 	// Do the request and read the body for non-error results.
 	resp, err := client.Do(req)
 	if err != nil {
+		logger.Printf("[ERROR] could not GET %q: %v\n", s.url, err)
 		return nil, err
 	}
 	defer resp.Body.Close()
 
 	bytes, err := ioutil.ReadAll(resp.Body)
 	if err != nil {
+		logger.Printf("[ERROR] could not read response from %q: %v\n", s.url, err)
 		return nil, err
 	}
 
@@ -64,6 +68,7 @@ func (s *HTTPSource) IP(timeout time.Duration) (net.IP, error) {
 	if s.parser != nil {
 		raw, err = s.parser(raw)
 		if err != nil {
+			logger.Printf("[ERROR] could not parse response from %q: %v\n", s.url, err)
 			return nil, err
 		}
 	}
@@ -71,6 +76,7 @@ func (s *HTTPSource) IP(timeout time.Duration) (net.IP, error) {
 	// validate the IP
 	externalIP := net.ParseIP(strings.TrimSpace(raw))
 	if externalIP == nil {
+		logger.Printf("[ERROR] %q returned an invalid IP: %v\n", s.url, err)
 		return nil, InvalidIPError(raw)
 	}
 

types.go

@@ -1,6 +1,7 @@
 package externalip
 
 import (
+	"log"
 	"net"
 	"time"
 )
@@ -11,7 +12,7 @@ type Source interface {
 	// net.IP should never be <nil> when error is <nil>
 	// It is recommended that the IP function times out,
 	// if no result could be found, after the given timeout duration.
-	IP(timeout time.Duration) (net.IP, error)
+	IP(timeout time.Duration, logger *log.Logger) (net.IP, error)
 }
 
 // voter adds weight to the IP given by a source.