Add a HTTP handler to the exvar package.

R=r
APPROVED=r
DELTA=20  (11 added, 6 deleted, 3 changed)
OCL=27782
CL=27950

src/lib/exvar.go

@@ -8,6 +8,8 @@ package exvar
 
 import (
 	"fmt";
+	"http";
+	"io";
 )
 
 // If mismatched names are used (e.g. calling IncrementInt on a mapVar), the
@@ -220,3 +222,12 @@ func String() string {
 	});
 	return s
 }
+
+// ExvarHandler is a HTTP handler that displays exported variables.
+// Use it like this:
+//   http.Handle("/exvar", http.HandlerFunc(exvar.ExvarHandler));
+func ExvarHandler(c *http.Conn, req *http.Request) {
+	// TODO(dsymonds): Support different output= args.
+	c.SetHeader("content-type", "text/plain; charset=utf-8");
+	io.WriteString(c, String());
+}

src/lib/http/triv.go

@@ -18,23 +18,17 @@ import (
 
 // hello world, the web server
 func HelloServer(c *http.Conn, req *http.Request) {
-	exvar.Increment("hello-requests", 1);
+	exvar.IncrementInt("hello-requests", 1);
 	io.WriteString(c, "hello, world!\n");
 }
 
-// Handler for /exvar requests.
-func ExvarServer(c *http.Conn, req *http.Request) {
-	c.SetHeader("content-type", "text/plain; charset=utf-8");
-	io.WriteString(c, exvar.String());
-}
-
 // simple counter server
 type Counter struct {
 	n int;
 }
 
 func (ctr *Counter) ServeHTTP(c *http.Conn, req *http.Request) {
-	exvar.Increment("counter-requests", 1);
+	exvar.IncrementInt("counter-requests", 1);
 	fmt.Fprintf(c, "counter = %d\n", ctr.n);
 	ctr.n++;
 }
@@ -101,7 +95,7 @@ func main() {
 	http.Handle("/args", http.HandlerFunc(ArgServer));
 	http.Handle("/go/hello", http.HandlerFunc(HelloServer));
 	http.Handle("/chan", ChanCreate());
-	http.Handle("/exvar", http.HandlerFunc(ExvarServer));
+	http.Handle("/exvar", http.HandlerFunc(exvar.ExvarHandler));
 	err := http.ListenAndServe(":12345", nil);
 	if err != nil {
 		panic("ListenAndServe: ", err.String())