launcher: add fix for long socket paths

Now relative path is used instead of real for console socket.
It is used to prevent console socket path from being too long.

Part of #124

cli/running/instance.go

@@ -5,6 +5,7 @@ import (
 	"os"
 	"os/exec"
 	"path/filepath"
+	"runtime"
 	"sync"
 	"syscall"
 	"time"
@@ -13,6 +14,11 @@ import (
 	"golang.org/x/sys/unix"
 )
 
+const (
+	maxSocketPathLinux = 108
+	maxSocketPathMac   = 106
+)
+
 // Instance describes a running process.
 type Instance struct {
 	// Cmd represents an external command being prepared and run.
@@ -104,9 +110,32 @@ func (inst *Instance) Start() error {
 		return err
 	}
 	inst.Cmd.Env = append(os.Environ(), "TT_CLI_INSTANCE="+inst.appPath)
-	inst.Cmd.Env = append(inst.Cmd.Env,
-		"TT_CLI_CONSOLE_SOCKET="+inst.consoleSocket)
 
+	// It became common that console socket path is longer than 108/106 (on linux/macOs).
+	// To reduce length of path we use relative path
+	// with chdir into a directory of console socket.
+	// e.g foo/bar/123.sock -> ./123.sock
+
+	maxSocketPath := maxSocketPathLinux
+	if runtime.GOOS == "darwin" {
+		maxSocketPath = maxSocketPathMac
+	}
+
+	if inst.consoleSocket != "" {
+		if len("./"+filepath.Base(inst.consoleSocket)) > maxSocketPath {
+			return fmt.Errorf("socket name is longer than %d symbols: %s",
+				maxSocketPath-2, filepath.Base(inst.consoleSocket))
+		}
+		inst.Cmd.Env = append(inst.Cmd.Env,
+			"TT_CLI_CONSOLE_SOCKET="+"unix/:./"+filepath.Base(inst.consoleSocket))
+		inst.Cmd.Env = append(inst.Cmd.Env,
+			"TT_CLI_CONSOLE_SOCKET_DIR="+filepath.Dir(inst.consoleSocket))
+	}
+	workDir, err := os.Getwd()
+	if err != nil {
+		return err
+	}
+	inst.Cmd.Env = append(inst.Cmd.Env, "TT_CLI_WORK_DIR="+workDir)
 	dataDirAbs := ""
 	if dataDirAbs, err = filepath.Abs(inst.dataDir); err != nil {
 		return err

cli/running/instance_test.go

@@ -87,8 +87,8 @@ func TestInstanceLogger(t *testing.T) {
 	defer writer.Close()
 	defer reader.Close()
 	logger := ttlog.NewCustomLogger(writer, "", 0)
-
-	inst := startTestInstance(t, "log_check_test_app", "", logger)
+	consoleSock := ""
+	inst := startTestInstance(t, "log_check_test_app", consoleSock, logger)
 	t.Cleanup(func() { cleanupTestInstance(inst) })
 
 	msg := "Check Log.\n"

cli/running/lua/launcher.lua

@@ -43,6 +43,10 @@ local origin_cfg = box.cfg
 
 --- Wrapper for cfg to push our values over tarantool.
 local function cfg_wrapper(cfg)
+    ffi.cdef([[
+        int chdir(const char *path);
+    ]])
+    ffi.C.chdir(os.getenv('TT_CLI_CONSOLE_SOCKET_DIR'))
     local cfg = cfg or {}
     local tt_cfg = {}
     tt_cfg.wal_dir = os.getenv('TT_WAL_DIR')
@@ -54,7 +58,8 @@ local function cfg_wrapper(cfg)
         end
     end
     local success, data = pcall(origin_cfg, cfg)
-    if not success then 
+    ffi.C.chdir(os.getenv('TT_CLI_WORK_DIR'))
+    if not success then
         log.error('Someting wrong happened when tried to set dataDir.')
     end
     return data
@@ -102,6 +107,19 @@ local function start_instance()
         ffi.C.setlinebuf(ffi.C.stdout)
     end
 
+    ffi.cdef([[
+        int chdir(const char *path);
+    ]])
+
+    -- It became common that console socket path is longer than 108 symbols(sun_path limit).
+	-- To reduce length of path we use relative path with
+    -- chdir into a directory of console socket.
+	-- e.g foo/bar/123.sock -> ./123.sock
+    local console_sock_dir = os.getenv('TT_CLI_CONSOLE_SOCKET_DIR')
+    if console_sock_dir ~= nil and console_sock_dir ~= '' then
+        ffi.C.chdir(console_sock_dir)
+    end
+
     -- If tarantool version is above 2.8.1, then can use environment variables
     -- instead of wrapping cfg.
     if not check_version({2,8,1,0}) then
@@ -127,6 +145,12 @@ local function start_instance()
 
     end
 
+    -- After making console socket chdir back to work directory.
+    local work_dir = os.getenv('TT_CLI_WORK_DIR')
+    if work_dir ~= nil and work_dir ~= '' then
+        ffi.C.chdir(work_dir)
+    end
+
     -- If stdin of the program was moved by command "tt run" to another fd
     -- then we need to move it back.
     -- It is used in cases when calling tarantool with "-" flag to hide input