daemon: add daemon module

`tt daemon` module is used to manage HTTP server
running on the background. HTTP server can process
`tt` commands such as `start`, `status`, etc.
Daemon can be configurated with `tt_daemon.yaml` config.

The following set of commands is implemented:

* `tt daemon start` - launch of a daemon;
* `tt daemon stop` - terminate of the daemon;
* `tt daemon status` - get daemon status;
* `tt daemon restart` - daemon restart.

Closes #10

Author: AnaNek

CHANGELOG.md

@@ -10,6 +10,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 ### Added
 
 - Module ``tt init``, to create tt environment configuration file.
+- Module ``tt daemon``, to manage the ``tt`` daemon.
 
 ## [0.1.0] - 2022-10-12
 

README.rst

@@ -293,6 +293,56 @@ use the .rockspec.
 
 `Custom template example <https://github.com/tarantool/tt/blob/master/doc/examples.rst#working-with-application-templates>`_
 
+Working with tt daemon (experimental)
+-------------------------------------
+
+``tt daemon`` module is used to manage ``tt`` running
+on the background on a given machine. This way instances
+can be operated remotely.
+Daemon can be configured with ``tt_daemon.yaml`` config.
+
+``tt_daemon.yaml`` file format:
+
+.. code-block:: yaml
+
+  daemon:
+        run_dir: path
+        log_dir: path
+        log_maxsize: num (MB)
+        log_maxage: num (Days)
+        log_maxbackups: num
+        log_file: string (file name)
+        listen_interface: string
+        port: num
+        pidfile: string (file name)
+
+Where:
+
+* ``run_dir`` (string) - path to directory that stores various instance
+  runtime artifacts like console socket, PID file, etc. Default: ``run``.
+* ``log_dir`` (string) - directory that stores log files. Default: ``log``.
+* ``log_maxsize`` (number) - the maximum size in MB of the log file before it gets
+  rotated. Default: 100 MB.
+* ``log_maxage`` (numder) - is the maximum number of days to retain old log files
+  based on the timestamp encoded in their filename. Note that a day is defined
+  as 24 hours and may not exactly correspond to calendar days due to daylight
+  savings, leap seconds, etc. Default: not to remove old log files based
+  on age.
+* ``log_maxbackups`` (number) - the maximum number of old log files to retain.
+  Default: to retain all old log files (though log_maxage may still cause
+  them to get deleted).
+* ``log_file`` (string) - name of file contains log of daemon process.
+  Default: ``tt_daemon.log``.
+* ``listen_interface`` (string) - network interface the IP address
+  should be found on to bind http server socket.
+  Default: loopback (``lo``/``lo0``).
+* ``port`` (number) - port number to be used for daemon http server.
+  Default: 1024.
+* ``pidfile`` (string) - name of file contains pid of daemon process.
+  Default: ``tt_daemon.pid``.
+
+`TT daemon example <https://github.com/tarantool/tt/blob/master/doc/examples.rst#working-with-tt-daemon>`_
+
 Commands
 --------
 Common description. For a detailed description, use ``tt help command`` .
@@ -319,3 +369,4 @@ Common description. For a detailed description, use ``tt help command`` .
 * ``install`` - install tarantool/tt.
 * ``remove`` - remove tarantool/tt.
 * ``init`` - create tt environment configuration file.
+* ``daemon (experimental)`` - manage tt daemon.

cli/cmd/daemon.go

@@ -0,0 +1,152 @@
+package cmd
+
+import (
+	"github.com/apex/log"
+	"github.com/spf13/cobra"
+	"github.com/tarantool/tt/cli/cmdcontext"
+	"github.com/tarantool/tt/cli/configure"
+	"github.com/tarantool/tt/cli/daemon"
+	"github.com/tarantool/tt/cli/modules"
+	"github.com/tarantool/tt/cli/process_utils"
+)
+
+// NewDaemonCmd creates daemon command.
+func NewDaemonCmd() *cobra.Command {
+	var daemonCmd = &cobra.Command{
+		Use:   "daemon",
+		Short: "Perform manipulations with the tt daemon (experimental)",
+	}
+
+	var startCmd = &cobra.Command{
+		Use:   "start",
+		Short: "start tt daemon",
+		Run: func(cmd *cobra.Command, args []string) {
+			if len(args) != 0 {
+				log.Fatalf("Wrong number of arguments")
+			}
+
+			err := modules.RunCmd(&cmdCtx, cmd.Name(), &modulesInfo,
+				internalDaemonStartModule, args)
+			if err != nil {
+				log.Fatalf(err.Error())
+			}
+		},
+	}
+
+	var stopCmd = &cobra.Command{
+		Use:   "stop",
+		Short: "stop tt daemon",
+		Run: func(cmd *cobra.Command, args []string) {
+			if len(args) != 0 {
+				log.Fatalf("Wrong number of arguments")
+			}
+
+			err := modules.RunCmd(&cmdCtx, cmd.Name(), &modulesInfo,
+				internalDaemonStopModule, args)
+			if err != nil {
+				log.Fatalf(err.Error())
+			}
+		},
+	}
+
+	var statusCmd = &cobra.Command{
+		Use:   "status",
+		Short: "status of tt daemon",
+		Run: func(cmd *cobra.Command, args []string) {
+			if len(args) != 0 {
+				log.Fatalf("Wrong number of arguments")
+			}
+
+			err := modules.RunCmd(&cmdCtx, cmd.Name(), &modulesInfo,
+				internalDaemonStatusModule, args)
+			if err != nil {
+				log.Fatalf(err.Error())
+			}
+		},
+	}
+
+	var restartCmd = &cobra.Command{
+		Use:   "restart",
+		Short: "restart tt daemon",
+		Run: func(cmd *cobra.Command, args []string) {
+			if len(args) != 0 {
+				log.Fatalf("Wrong number of arguments")
+			}
+
+			err := modules.RunCmd(&cmdCtx, cmd.Name(), &modulesInfo,
+				internalDaemonRestartModule, args)
+			if err != nil {
+				log.Fatalf(err.Error())
+			}
+		},
+	}
+
+	daemonSubCommands := []*cobra.Command{
+		startCmd,
+		stopCmd,
+		statusCmd,
+		restartCmd,
+	}
+
+	for _, cmd := range daemonSubCommands {
+		daemonCmd.AddCommand(cmd)
+	}
+
+	return daemonCmd
+}
+
+// internalDaemonStartModule is a default restart module.
+func internalDaemonRestartModule(cmdCtx *cmdcontext.CmdCtx, args []string) error {
+	if err := internalDaemonStopModule(cmdCtx, args); err != nil {
+		return err
+	}
+
+	if err := internalDaemonStartModule(cmdCtx, args); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// internalDaemonStartModule is a default start module.
+func internalDaemonStartModule(cmdCtx *cmdcontext.CmdCtx, args []string) error {
+	opts, err := configure.GetDaemonOpts(cmdCtx.Cli.DaemonCfgPath)
+	if err != nil {
+		return err
+	}
+
+	daemonCtx := daemon.NewDaemonCtx(opts)
+	if err := daemon.RunHTTPServerOnBackground(daemonCtx); err != nil {
+		log.Fatalf(err.Error())
+	}
+
+	return nil
+}
+
+// internalDaemonStopModule is a default stop module.
+func internalDaemonStopModule(cmdCtx *cmdcontext.CmdCtx, args []string) error {
+	opts, err := configure.GetDaemonOpts(cmdCtx.Cli.DaemonCfgPath)
+	if err != nil {
+		return err
+	}
+
+	daemonCtx := daemon.NewDaemonCtx(opts)
+	if err := process_utils.StopProcess(daemonCtx.PIDFile, "", "Daemon"); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// internalDaemonStatusModule is a default status module.
+func internalDaemonStatusModule(cmdCtx *cmdcontext.CmdCtx, args []string) error {
+	opts, err := configure.GetDaemonOpts(cmdCtx.Cli.DaemonCfgPath)
+	if err != nil {
+		return err
+	}
+
+	daemonCtx := daemon.NewDaemonCtx(opts)
+	log.Info(process_utils.ProcessStatus(daemonCtx.PIDFile))
+
+	return nil
+}

cli/cmd/root.go

@@ -117,6 +117,7 @@ func NewCmdRoot() *cobra.Command {
 		NewRemoveCmd(),
 		NewPackCmd(),
 		NewInitCmd(),
+		NewDaemonCmd(),
 	)
 	if err := injectCmds(rootCmd); err != nil {
 		panic(err.Error())

cli/cmdcontext/cmdcontext.go

@@ -21,6 +21,8 @@ type CliCtx struct {
 	LocalLaunchDir string
 	// Path to Tarantool CLI (tarantool.yaml) config.
 	ConfigPath string
+	// Path to tt daemon (tt_daemon.yaml) config.
+	DaemonCfgPath string
 	// Path to Tarantool executable (detected if CLI launch is local).
 	TarantoolExecutable string
 	// Tarantool version.

cli/config/daemon_cfg.go

@@ -0,0 +1,52 @@
+package config
+
+// DaemonCfg used to store all information from the
+// tt_daemon.yaml configuration file.
+type DaemonCfg struct {
+	DaemonConfig *DaemonOpts `mapstructure:"daemon" yaml:"daemon"`
+}
+
+// DaemonOpts stores information about tt daemon configuration.
+// Filled in when parsing the tt_daemon.yaml configuration file.
+//
+// tt_daemon.yaml file format:
+// daemon:
+//
+//	run_dir: path
+//	log_dir: path
+//	log_maxsize: num (MB)
+//	log_maxage: num (Days)
+//	log_maxbackups: num
+//	log_file: string (file name)
+//	listen_interface: string
+//	port: num
+//	pidfile: string (file name)
+type DaemonOpts struct {
+	// PIDFile is name of file contains pid of daemon process.
+	PIDFile string `mapstructure:"pidfile"`
+	// Port is a port number to be used for daemon http server.
+	Port int `mapstructure:"port"`
+	// LogDir is a directory that stores log files.
+	LogDir string `mapstructure:"log_dir"`
+	// LogFile is a name of file contains log of daemon process.
+	LogFile string `mapstructure:"log_file"`
+	// LogMaxSize is a maximum size in MB of the log file before
+	// it gets rotated.
+	LogMaxSize int `mapstructure:"log_maxsize"`
+	// LogMaxAge is the maximum number of days to retain old log files
+	// based on the timestamp encoded in their filename. Note that a
+	// day is defined as 24 hours and may not exactly correspond to
+	// calendar days due to daylight savings, leap seconds, etc. The
+	// default is not to remove old log files based on age.
+	LogMaxAge int `mapstructure:"log_maxage"`
+	// LogMaxBackups is the maximum number of old log files to retain.
+	// The default is to retain all old log files (though LogMaxAge may
+	// still cause them to get deleted).
+	LogMaxBackups int `mapstructure:"log_maxbackups"`
+	// ListenInterface is a network interface the IP address
+	// should be found on to bind http server socket.
+	ListenInterface string `mapstructure:"listen_interface"`
+	// RunDir is a path to directory that stores various instance
+	// runtime artifacts like console socket, PID file, etc.
+	RunDir string `mapstructure:"run_dir" yaml:"run_dir"`
+}