Add --git-config flag

This allows arbitrary git configs to be passed in.  For example:

`git config --global http.postBuffer 1048576000`

`git config --global http.sslCAInfo /path/to/cert/file`

`git config --global http.sslVerify false`

This flag takes a comma-separated list of `key:val` pairs.  The key part
is passed to `git config` and must be a valid gitconfig section header
and variable name.  The val part can be either a quoted or unquoted
value.  For all values the following escape sequences are supported:
   * `\n` => [newline]
   * `\t` => [tab]
   * `\"` => `"`
   * `\,` => `,`
   * `\\` => `\`

Within unquoted values, commas MUST be escaped. Within quoted values,
commas MAY be escaped, but are not required to be.  Any other escape
sequence is an error.

Example:

`--git-config=foo.one:val1,foo.two:"quoted val",foo.three:12345`

This commit exposed a bug in runCommand() which modified its args when
they had an embedded space.

README.md

@@ -115,5 +115,6 @@ docker run -d \
 | GIT_SYNC_HTTP_BIND              | `--http-bind`              | the bind address (including port) for git-sync's HTTP endpoint                                                                                                                                                                                | ""                            |
 | GIT_SYNC_HTTP_METRICS           | `--http-metrics`           | enable metrics on git-sync's HTTP endpoint                                                                                                                                                                                                    | true                          |
 | GIT_SYNC_HTTP_PPROF             | `--http-pprof`             | enable the pprof debug endpoints on git-sync's HTTP endpoint                                                                                                                                                                                  | false                         |
+| GIT_SYNC_GIT_CONFIG             | `--git-config`             | additional git config options in 'key1:val1,key2:val2' format                                                                                                                                                                                 | ""                            |
 
 [![Analytics](https://kubernetes-site.appspot.com/UA-36037335-10/GitHub/git-sync/README.md?pixel)]()

cmd/git-sync/main.go

@@ -115,6 +115,8 @@ var flAskPassURL = pflag.String("askpass-url", envString("GIT_ASKPASS_URL", ""),
 
 var flGitCmd = pflag.String("git", envString("GIT_SYNC_GIT", "git"),
 	"the git command to run (subject to PATH search, mostly for testing)")
+var flGitConfig = pflag.String("git-config", envString("GIT_SYNC_GIT_CONFIG", ""),
+	"additional git config options in 'key1:val1,key2:val2' format")
 
 var flHTTPBind = pflag.String("http-bind", envString("GIT_SYNC_HTTP_BIND", ""),
 	"the bind address (including port) for git-sync's HTTP endpoint")
@@ -485,6 +487,14 @@ func main() {
 		}
 	}
 
+	// This needs to be after all other git-related config flags.
+	if *flGitConfig != "" {
+		if err := setupExtraGitConfigs(ctx, *flGitConfig); err != nil {
+			log.Error(err, "ERROR: can't set additional git configs")
+			os.Exit(1)
+		}
+	}
+
 	// The scope of the initialization context ends here, so we call cancel to release resources associated with it.
 	cancel()
 
@@ -941,12 +951,15 @@ func cmdForLog(command string, args ...string) string {
 	if strings.ContainsAny(command, " \t\n") {
 		command = fmt.Sprintf("%q", command)
 	}
+	// Don't modify the passed-in args.
+	argsCopy := make([]string, len(args))
+	copy(argsCopy, args)
 	for i := range args {
 		if strings.ContainsAny(args[i], " \t\n") {
-			args[i] = fmt.Sprintf("%q", args[i])
+			argsCopy[i] = fmt.Sprintf("%q", args[i])
 		}
 	}
-	return command + " " + strings.Join(args, " ")
+	return command + " " + strings.Join(argsCopy, " ")
 }
 
 func runCommand(ctx context.Context, cwd, command string, args ...string) (string, error) {
@@ -1039,8 +1052,7 @@ func (git *repoSync) SetupCookieFile(ctx context.Context) error {
 		return fmt.Errorf("can't access git cookiefile: %w", err)
 	}
 
-	if _, err = runCommand(ctx, "",
+	if _, err = runCommand(ctx, "", git.cmd, "config", "--global", "http.cookiefile", pathToCookieFile); err != nil {
-		git.cmd, "config", "--global", "http.cookiefile", pathToCookieFile); err != nil {
 		return fmt.Errorf("can't configure git cookiefile: %w", err)
 	}
 
@@ -1102,6 +1114,167 @@ func (git *repoSync) CallAskPassURL(ctx context.Context) error {
 	return nil
 }
 
+func setupExtraGitConfigs(ctx context.Context, configsFlag string) error {
+	log.V(1).Info("setting additional git configs")
+
+	configs, err := parseGitConfigs(configsFlag)
+	if err != nil {
+		return fmt.Errorf("can't parse --git-config flag: %v", err)
+	}
+	for _, kv := range configs {
+		if _, err := runCommand(ctx, "", *flGitCmd, "config", "--global", kv.key, kv.val); err != nil {
+			return fmt.Errorf("error configuring additional git configs %q %q: %v", kv.key, kv.val, err)
+		}
+	}
+
+	return nil
+}
+
+type keyVal struct {
+	key string
+	val string
+}
+
+func parseGitConfigs(configsFlag string) ([]keyVal, error) {
+	ch := make(chan rune)
+	stop := make(chan bool)
+	go func() {
+		for _, r := range configsFlag {
+			select {
+			case <-stop:
+				break
+			default:
+				ch <- r
+			}
+		}
+		close(ch)
+		return
+	}()
+
+	result := []keyVal{}
+
+	// This assumes it is at the start of a key.
+	for {
+		cur := keyVal{}
+		var err error
+
+		// Peek and see if we have a key.
+		if r, ok := <-ch; !ok {
+			break
+		} else {
+			cur.key, err = parseGitConfigKey(r, ch)
+			if err != nil {
+				return nil, err
+			}
+		}
+
+		// Peek and see if we have a value.
+		if r, ok := <-ch; !ok {
+			return nil, fmt.Errorf("key %q: no value", cur.key)
+		} else {
+			if r == '"' {
+				cur.val, err = parseGitConfigQVal(ch)
+				if err != nil {
+					return nil, fmt.Errorf("key %q: %v", cur.key, err)
+				}
+			} else {
+				cur.val, err = parseGitConfigVal(r, ch)
+				if err != nil {
+					return nil, fmt.Errorf("key %q: %v", cur.key, err)
+				}
+			}
+		}
+
+		result = append(result, cur)
+	}
+
+	return result, nil
+}
+
+func parseGitConfigKey(r rune, ch <-chan rune) (string, error) {
+	buf := make([]rune, 0, 64)
+	buf = append(buf, r)
+
+	for r := range ch {
+		switch {
+		case r == ':':
+			return string(buf), nil
+		default:
+			// This can accumulate things that git doesn't allow, but we'll
+			// just let git handle it, rather than try to pre-validate to their
+			// spec.
+			buf = append(buf, r)
+		}
+	}
+	return "", fmt.Errorf("unexpected end of key: %q", string(buf))
+}
+
+func parseGitConfigQVal(ch <-chan rune) (string, error) {
+	buf := make([]rune, 0, 64)
+
+	for r := range ch {
+		switch r {
+		case '\\':
+			if e, err := unescape(ch); err != nil {
+				return "", err
+			} else {
+				buf = append(buf, e)
+			}
+		case '"':
+			// Once we have a closing quote, the next must be either a comma or
+			// end-of-string.  This helps reset the state for the next key, if
+			// there is one.
+			r, ok := <-ch
+			if ok && r != ',' {
+				return "", fmt.Errorf("unexpected trailing character '%c'", r)
+			}
+			return string(buf), nil
+		default:
+			buf = append(buf, r)
+		}
+	}
+	return "", fmt.Errorf("unexpected end of value: %q", string(buf))
+}
+
+func parseGitConfigVal(r rune, ch <-chan rune) (string, error) {
+	buf := make([]rune, 0, 64)
+	buf = append(buf, r)
+
+	for r := range ch {
+		switch r {
+		case '\\':
+			if r, err := unescape(ch); err != nil {
+				return "", err
+			} else {
+				buf = append(buf, r)
+			}
+		case ',':
+			return string(buf), nil
+		default:
+			buf = append(buf, r)
+		}
+	}
+	// We ran out of characters, but that's OK.
+	return string(buf), nil
+}
+
+// unescape processes most of the documented escapes that git config supports.
+func unescape(ch <-chan rune) (rune, error) {
+	r, ok := <-ch
+	if !ok {
+		return 0, fmt.Errorf("unexpected end of escape sequence")
+	}
+	switch r {
+	case 'n':
+		return '\n', nil
+	case 't':
+		return '\t', nil
+	case '"', ',', '\\':
+		return r, nil
+	}
+	return 0, fmt.Errorf("unsupported escape character: '%c'", r)
+}
+
 // This string is formatted for 80 columns.  Please keep it that way.
 // DO NOT USE TABS.
 var manual = `
@@ -1164,17 +1337,20 @@ OPTIONS
             Create a shallow clone with history truncated to the specified
             number of commits.
 
-    --link <string>, $GIT_SYNC_LINK
-            The name of the final symlink (under --root) which will point to the
-            current git worktree. This must be a filename, not a path, and may
-            not start with a period. The destination of this link (i.e.
-            readlink()) is the currently checked out SHA. (default: the leaf
-            dir of --repo)
-
     --git <string>, $GIT_SYNC_GIT
             The git command to run (subject to PATH search, mostly for testing).
             (default: git)
 
+    --git-config <string>, $GIT_SYNC_GIT_CONFIG
+            Additional git config options in 'key1:val1,key2:val2' format.  The
+            key parts are passed to 'git config' and must be valid syntax for
+            that command.  The val parts can be either quoted or unquoted
+            values.  For all values the following escape sequences are
+            supported: '\n' => [newline], '\t' => [tab], '\"' => '"', '\,' =>
+            ',', '\\' => '\'.  Within unquoted values, commas MUST be escaped.
+            Within quoted values, commas MAY be escaped, but are not required
+            to be.  Any other escape sequence is an error. (default: "")
+
     -h, --help
             Print help text and exit.
 
@@ -1190,6 +1366,13 @@ OPTIONS
             Enable the pprof debug endpoints on git-sync's HTTP endpoint (see
             --http-bind). (default: false)
 
+    --link <string>, $GIT_SYNC_LINK
+            The name of the final symlink (under --root) which will point to the
+            current git worktree. This must be a filename, not a path, and may
+            not start with a period. The destination of this link (i.e.
+            readlink()) is the currently checked out SHA. (default: the leaf
+            dir of --repo)
+
     --man
             Print this manual and exit.
 

cmd/git-sync/main_test.go

@@ -18,6 +18,7 @@ package main
 
 import (
 	"os"
+	"reflect"
 	"strings"
 	"testing"
 	"time"
@@ -150,3 +151,91 @@ func TestManualHasNoTabs(t *testing.T) {
 		t.Fatal("the manual text contains a tab")
 	}
 }
+
+func TestParseGitConfigs(t *testing.T) {
+	cases := []struct {
+		name   string
+		input  string
+		expect []keyVal
+		fail   bool
+	}{{
+		name:   "empty",
+		input:  ``,
+		expect: []keyVal{},
+	}, {
+		name:   "one-pair",
+		input:  `k:v`,
+		expect: []keyVal{keyVal{"k", "v"}},
+	}, {
+		name:   "one-pair-qval",
+		input:  `k:"v"`,
+		expect: []keyVal{keyVal{"k", "v"}},
+	}, {
+		name:  "garbage",
+		input: `abc123`,
+		fail:  true,
+	}, {
+		name:  "invalid-val",
+		input: `k:v\xv`,
+		fail:  true,
+	}, {
+		name:  "invalid-qval",
+		input: `k:"v\xv"`,
+		fail:  true,
+	}, {
+		name:   "two-pair",
+		input:  `k1:v1,k2:v2`,
+		expect: []keyVal{{"k1", "v1"}, {"k2", "v2"}},
+	}, {
+		name:   "val-spaces",
+		input:  `k1:v 1,k2:v 2`,
+		expect: []keyVal{{"k1", "v 1"}, {"k2", "v 2"}},
+	}, {
+		name:   "qval-spaces",
+		input:  `k1:" v 1 ",k2:" v 2 "`,
+		expect: []keyVal{{"k1", " v 1 "}, {"k2", " v 2 "}},
+	}, {
+		name:   "mix-val-qval",
+		input:  `k1:v 1,k2:" v 2 "`,
+		expect: []keyVal{{"k1", "v 1"}, {"k2", " v 2 "}},
+	}, {
+		name:  "garbage-after-qval",
+		input: `k1:"v1"x,k2:"v2"`,
+		fail:  true,
+	}, {
+		name:   "dangling-comma",
+		input:  `k1:"v1",k2:"v2",`,
+		expect: []keyVal{{"k1", "v1"}, {"k2", "v2"}},
+	}, {
+		name:   "val-escapes",
+		input:  `k1:v\n\t\\\"\,1`,
+		expect: []keyVal{{"k1", "v\n\t\\\",1"}},
+	}, {
+		name:   "qval-escapes",
+		input:  `k1:"v\n\t\\\"\,1"`,
+		expect: []keyVal{{"k1", "v\n\t\\\",1"}},
+	}, {
+		name:   "qval-comma",
+		input:  `k1:"v,1"`,
+		expect: []keyVal{{"k1", "v,1"}},
+	}, {
+		name:  "qval-missing-close",
+		input: `k1:"v1`,
+		fail:  true,
+	}}
+
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			kvs, err := parseGitConfigs(tc.input)
+			if err != nil && !tc.fail {
+				t.Errorf("unexpected error: %v", err)
+			}
+			if err == nil && tc.fail {
+				t.Errorf("unexpected success")
+			}
+			if !reflect.DeepEqual(kvs, tc.expect) {
+				t.Errorf("bad result: expected %v, got %v", tc.expect, kvs)
+			}
+		})
+	}
+}

test_e2e.sh

@@ -1233,6 +1233,27 @@ assert_file_eq "$ROOT"/link/file "$TESTCASE"
 # Wrap up
 pass
 
+##############################################
+# Test additional git configs
+##############################################
+testcase "additional-git-configs"
+echo "$TESTCASE" > "$REPO"/file
+git -C "$REPO" commit -qam "$TESTCASE"
+GIT_SYNC \
+    --one-time \
+    --repo="file://$REPO" \
+    --branch=e2e-branch \
+    --rev=HEAD \
+    --root="$ROOT" \
+    --link="link" \
+    --git-config='http.postBuffer:10485760,sect.k1:"a val",sect.k2:another val' \
+    > "$DIR"/log."$TESTCASE" 2>&1
+assert_link_exists "$ROOT"/link
+assert_file_exists "$ROOT"/link/file
+assert_file_eq "$ROOT"/link/file "$TESTCASE"
+# Wrap up
+pass
+
 echo
 echo "all tests passed: cleaning up $DIR"
 rm -rf "$DIR"