Add optional logging of rate-limiting headers

* Disabled by default
* Fix #77.

log.go

@@ -1,6 +1,12 @@
 package anaconda
 
-// Logger interface to allow us to log
+import (
+	"log"
+	"os"
+)
+
+// The Logger interface provides optional logging ability for the streaming API.
+// It can also be used to log the rate limiting headers if desired.
 type Logger interface {
 	Fatal(args ...interface{})
 	Fatalf(format string, args ...interface{})
@@ -54,3 +60,32 @@ func (_ silentLogger) Info(_ ...interface{})                  {}
 func (_ silentLogger) Infof(_ string, _ ...interface{})       {}
 func (_ silentLogger) Debug(_ ...interface{})                 {}
 func (_ silentLogger) Debugf(format string, _ ...interface{}) {}
+
+// BasicLogger is the equivalent of using log from the standard
+// library to print to STDERR
+var BasicLogger Logger
+
+type basicLogger struct {
+	log *log.Logger //func New(out io.Writer, prefix string, flag int) *Logger
+}
+
+func init() {
+	BasicLogger = &basicLogger{log: log.New(os.Stderr, log.Prefix(), log.LstdFlags)}
+}
+
+func (l basicLogger) Fatal(items ...interface{})               { l.log.Fatal(items) }
+func (l basicLogger) Fatalf(s string, items ...interface{})    { l.log.Fatalf(s, items) }
+func (l basicLogger) Panic(items ...interface{})               { l.log.Panic(items) }
+func (l basicLogger) Panicf(s string, items ...interface{})    { l.log.Panicf(s, items) }
+func (l basicLogger) Critical(items ...interface{})            { l.log.Print(items) }
+func (l basicLogger) Criticalf(s string, items ...interface{}) { l.log.Printf(s, items) }
+func (l basicLogger) Error(items ...interface{})               { l.log.Print(items) }
+func (l basicLogger) Errorf(s string, items ...interface{})    { l.log.Printf(s, items) }
+func (l basicLogger) Warning(items ...interface{})             { l.log.Print(items) }
+func (l basicLogger) Warningf(s string, items ...interface{})  { l.log.Printf(s, items) }
+func (l basicLogger) Notice(items ...interface{})              { l.log.Print(items) }
+func (l basicLogger) Noticef(s string, items ...interface{})   { l.log.Printf(s, items) }
+func (l basicLogger) Info(items ...interface{})                { l.log.Print(items) }
+func (l basicLogger) Infof(s string, items ...interface{})     { l.log.Printf(s, items) }
+func (l basicLogger) Debug(items ...interface{})               { l.log.Print(items) }
+func (l basicLogger) Debugf(s string, items ...interface{})    { l.log.Printf(s, items) }

streaming.go

@@ -121,6 +121,9 @@ type TooManyFollow struct {
 
 // TODO: Site Stream messages. I cant test.
 
+// TODO: May be we could pass it a Logger interface to allow the
+// stream to log in the right place ?
+
 // Stream allows you to stream using one of the
 // PublicStream* or UserStream api methods
 //
@@ -139,8 +142,7 @@ type TooManyFollow struct {
 //
 // When finished you can call stream.Close() to terminate remote connection.
 //
-// May be we could pass it a Logger interface to allow the
-// stream to log in the right place ?
+
 type Stream struct {
 	api       TwitterApi
 	C         chan interface{}

twitter.go

@@ -73,6 +73,7 @@ type TwitterApi struct {
 	HttpClient           *http.Client
 
 	// Currently used only for the streaming API
+	// and for checking rate-limiting headers
 	// Default logger is silent
 	Log Logger
 }
@@ -249,6 +250,8 @@ func (c *TwitterApi) throttledQuery() {
 		if err != nil {
 			if apiErr, ok := err.(*ApiError); ok {
 				if isRateLimitError, nextWindow := apiErr.RateLimitCheck(); isRateLimitError && !c.returnRateLimitError {
+					c.Log.Info(apiErr.Error())
+
 					// If this is a rate-limiting error, re-add the job to the queue
 					// TODO it really should preserve order
 					go func() {