From e21069f3ab2ff6b8956011327466ec75697a4605 Mon Sep 17 00:00:00 2001
From: Michael Bridgen <mikeb@squaremobius.net>
Date: Wed, 22 Oct 2014 11:58:55 +0100
Subject: [PATCH] Factored out HTTP error + log

---
 server/http.go | 55 +++++++++++++++++++++++++++++++++-----------------
 1 file changed, 37 insertions(+), 18 deletions(-)

diff --git a/server/http.go b/server/http.go
index 69755620..7bdce9ce 100644
--- a/server/http.go
+++ b/server/http.go
@@ -4,6 +4,7 @@ import (
 	"errors"
 	"fmt"
 	"github.com/miekg/dns"
+	"log"
 	"net"
 	"net/http"
 	"strings"
@@ -18,75 +19,93 @@ func parseUrl(url string) (identifier string, ipaddr string, err error) {
 	return parts[2], parts[3], nil
 }
 
+func httpErrorAndLog(level *log.Logger, w http.ResponseWriter, msg string,
+	status int, logmsg string, logargs ...interface{}) {
+	http.Error(w, msg, status)
+	level.Printf(logmsg, logargs...)
+}
+
 func ListenHttp(domain string, db Zone, port int) {
 	http.HandleFunc("/name/", func(w http.ResponseWriter, r *http.Request) {
+
+		reqError := func(msg string, logmsg string, logargs ...interface{}) {
+			httpErrorAndLog(Warning, w, msg, http.StatusBadRequest,
+				logmsg, logargs...)
+		}
+
 		switch r.Method {
 		case "PUT":
 			identifier, weave_ipstr, err := parseUrl(r.URL.Path)
 			name := r.FormValue("fqdn")
 			prefix := r.FormValue("routing_prefix")
 			local_ip := r.FormValue("local_ip")
+
 			if identifier == "" || weave_ipstr == "" || name == "" || prefix == "" || local_ip == "" {
-				Warning.Printf("Invalid request: %s, %s", r.URL, r.Form)
-				http.Error(w, "Invalid Request", http.StatusBadRequest)
+				reqError("Invalid request", "Invalid request: %s, %s", r.URL, r.Form)
 				return
 			}
+
 			ip := net.ParseIP(local_ip)
 			if ip == nil {
-				Warning.Printf("Invalid IP in request: %s", local_ip)
-				http.Error(w, "Invalid IP in request", http.StatusBadRequest)
+				reqError("Invalid IP in request", "Invalid IP in request: %s", local_ip)
 				return
 			}
+
 			weave_cidr := weave_ipstr + "/" + prefix
 			weave_ip, subnet, err := net.ParseCIDR(weave_cidr)
 			if err != nil {
-				Warning.Printf("Invalid CIDR in request: %s", weave_cidr)
-				http.Error(w, fmt.Sprintf("Invalid CIDR: %s", weave_cidr), http.StatusBadRequest)
+				reqError("Invalid CIDR", "Invalid CIDR in request: %s", weave_cidr)
 				return
 			}
+
 			if dns.IsSubDomain(domain, name) {
 				Info.Printf("Adding %s (%s) -> %s", name, local_ip, weave_cidr)
 				err = db.AddRecord(identifier, name, ip, weave_ip, subnet)
 				if err != nil {
 					dup, ok := err.(DuplicateError)
 					if !ok {
-						Error.Print("Unexpected error from DB", err)
-						http.Error(w, "Internal error", http.StatusInternalServerError)
+						httpErrorAndLog(
+							Error, w, "Internal error", http.StatusInternalServerError,
+							"Unexpected error from DB", err)
+						return
 					} else if dup.Ident != identifier {
 						http.Error(w, err.Error(), http.StatusConflict)
-					}
-					return
+						return
+					} // else we are golden
 				}
 			} else {
 				Info.Printf("Ignoring name %s, not in %s", name, domain)
 			}
+
 		case "DELETE":
 			identifier, weave_ipstr, err := parseUrl(r.URL.Path)
 			if identifier == "" || weave_ipstr == "" {
-				Warning.Printf("Invalid request: %s, %s", r.URL, r.Form)
-				http.Error(w, "Invalid Request", http.StatusBadRequest)
+				reqError("Invalid Request", "Invalid request: %s, %s", r.URL, r.Form)
 				return
 			}
+
 			weave_ip := net.ParseIP(weave_ipstr)
 			if weave_ip == nil {
-				Warning.Printf("Invalid IP in request: %s", weave_ipstr)
-				http.Error(w, "Invalid IP in request", http.StatusBadRequest)
+				reqError("Invalid IP in request", "Invalid IP in request: %s", weave_ipstr)
 				return
 			}
 			Info.Printf("Deleting %s (%s)", identifier, weave_ipstr)
 			err = db.DeleteRecord(identifier, weave_ip)
 			if err != nil {
 				if _, ok := err.(LookupError); !ok {
-					Error.Print("Unexpected error from DB", err)
-					http.Error(w, "Internal error", http.StatusInternalServerError)
+					httpErrorAndLog(
+						Error, w, "Internal error", http.StatusInternalServerError,
+						"Unexpected error from DB", err)
 					return
 				}
 			}
 		default:
-			Warning.Println("Unexpected http method", r.Method)
-			http.Error(w, "Unexpected http method: "+r.Method, http.StatusBadRequest)
+			msg := "Unexpected http method: " + r.Method
+			reqError(msg, msg)
+			return
 		}
 	})
+
 	address := fmt.Sprintf(":%d", port)
 	err := http.ListenAndServe(address, nil)
 	if err != nil {