many: replace most uses of strings.SplitN with Cut

In most cases Cut(s, sep) is clearer than strings.SplitN(s, sep, 2).

Change-Id: I375c15f778e43ff25b5b74c9ad0e96dac4615786
Reviewed-on: https://go-review.googlesource.com/c/pkgsite/+/347889
Trust: Jonathan Amsterdam <jba@google.com>
Run-TryBot: Jonathan Amsterdam <jba@google.com>
TryBot-Result: kokoro <noreply+kokoro@google.com>
Reviewed-by: Julie Qiu <julie@golang.org>

2 files changed, 11 insertions, 12 deletions

diff --git a/internal/config/config.go b/internal/config/config.go
index 7b1e9349..3f243db7 100644
--- a/internal/config/config.go
+++ b/internal/config/config.go
@@ -27,6 +27,7 @@ import (
 	"cloud.google.com/go/storage"
 	"github.com/ghodss/yaml"
 	"golang.org/x/net/context/ctxhttp"
+	"golang.org/x/pkgsite/internal"
 	"golang.org/x/pkgsite/internal/derrors"
 	"golang.org/x/pkgsite/internal/log"
 	"golang.org/x/pkgsite/internal/secrets"
@@ -277,14 +278,14 @@ func (c *Config) DeploymentEnvironment() string {
 	if c.ServiceID == "" {
 		return "local"
 	}
-	parts := strings.SplitN(c.ServiceID, "-", 2)
-	if len(parts) == 1 {
+	before, _, found := internal.Cut(c.ServiceID, "-")
+	if !found {
 		return "prod"
 	}
-	if parts[0] == "" {
+	if before == "" {
 		return "unknownEnv"
 	}
-	return parts[0]
+	return before
 }
 
 // Application returns the name of the running application: "worker",
@@ -293,12 +294,12 @@ func (c *Config) Application() string {
 	if c.ServiceID == "" {
 		return "unknownApp"
 	}
-	parts := strings.SplitN(c.ServiceID, "-", 2)
+	before, after, found := internal.Cut(c.ServiceID, "-")
 	var svc string
-	if len(parts) == 1 {
-		svc = parts[0]
+	if !found {
+		svc = before
 	} else {
-		svc = parts[1]
+		svc = after
 	}
 	switch svc {
 	case "default":
diff --git a/internal/config/dynconfig/dynconfig.go b/internal/config/dynconfig/dynconfig.go
index 9c2e2342..29e65d17 100644
--- a/internal/config/dynconfig/dynconfig.go
+++ b/internal/config/dynconfig/dynconfig.go
@@ -40,12 +40,10 @@ func Read(ctx context.Context, location string) (_ *DynamicConfig, err error) {
 	log.Debugf(ctx, "reading dynamic config from %s", location)
 	var r io.ReadCloser
 	if strings.HasPrefix(location, "gs://") {
-		parts := strings.SplitN(location[5:], "/", 2)
-		if len(parts) != 2 {
+		bucket, object, found := internal.Cut(location[5:], "/")
+		if !found {
 			return nil, errors.New("bad GCS URL")
 		}
-		bucket := parts[0]
-		object := parts[1]
 		if err != nil {
 			return nil, err
 		}