move ssh regexp test to common location

- include testing
- improve hostname checking

Signed-off-by: Alex Couture-Beil <alex@earthly.dev>

client/llb/source.go

@@ -5,7 +5,6 @@ import (
 	_ "crypto/sha256" // for opencontainers/go-digest
 	"encoding/json"
 	"os"
-	"regexp"
 	"strconv"
 	"strings"
 
@@ -207,8 +206,6 @@ const (
 	gitProtocolUnknown
 )
 
-var gitSSHRegex = regexp.MustCompile("^[a-z0-9]+@[^:]+:.*$")
-
 func getGitProtocol(remote string) (string, int) {
 	prefixes := map[string]int{
 		"http://":  gitProtocolHTTP,
@@ -224,7 +221,7 @@ func getGitProtocol(remote string) (string, int) {
 		}
 	}
 
-	if protocolType == gitProtocolUnknown && gitSSHRegex.MatchString(remote) {
+	if protocolType == gitProtocolUnknown && sshutil.IsSSHTransport(remote) {
 		protocolType = gitProtocolSSH
 	}
 

source/gitidentifier.go

@@ -2,9 +2,9 @@ package source
 
 import (
 	"net/url"
-	"regexp"
 	"strings"
 
+	"github.com/moby/buildkit/util/sshutil"
 	"github.com/pkg/errors"
 )
 
@@ -19,8 +19,6 @@ type GitIdentifier struct {
 	KnownSSHHosts    string
 }
 
-var gitSSHRegex = regexp.MustCompile("^[a-z0-9]+@[^:]+:.*$")
-
 func NewGitIdentifier(remoteURL string) (*GitIdentifier, error) {
 	repo := GitIdentifier{}
 
@@ -61,7 +59,7 @@ func (i *GitIdentifier) ID() string {
 // isGitTransport returns true if the provided str is a git transport by inspecting
 // the prefix of the string for known protocols used in git.
 func isGitTransport(str string) bool {
-	return strings.HasPrefix(str, "http://") || strings.HasPrefix(str, "https://") || strings.HasPrefix(str, "git://") || gitSSHRegex.MatchString(str)
+	return strings.HasPrefix(str, "http://") || strings.HasPrefix(str, "https://") || strings.HasPrefix(str, "git://") || sshutil.IsSSHTransport(str)
 }
 
 func getRefAndSubdir(fragment string) (ref string, subdir string) {

util/sshutil/transport_validation.go

@@ -0,0 +1,11 @@
+package sshutil
+
+import (
+	"regexp"
+)
+
+var gitSSHRegex = regexp.MustCompile("^[a-z0-9]+@[a-zA-Z0-9-.]+:.*$")
+
+func IsSSHTransport(s string) bool {
+	return gitSSHRegex.MatchString(s)
+}

util/sshutil/transport_validation_test.go

@@ -0,0 +1,14 @@
+package sshutil
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestIsSSHTransport(t *testing.T) {
+	require.False(t, IsSSHTransport("http://github.com/moby/buildkit"))
+	require.False(t, IsSSHTransport("github.com/moby/buildkit"))
+	require.True(t, IsSSHTransport("git@github.com:moby/buildkit.git"))
+	require.True(t, IsSSHTransport("nonstandarduser@example.com:/srv/repos/weird/project.git"))
+}