allow to set default arguments values from env vars

README.md

@@ -49,13 +49,14 @@ Alternately you can use distro packages:
 
 The `sftpgo` executable supports the following command line flags:
 
-- `--config-dir` string. Location of the config dir. This directory should contain the `sftpgo.conf` configuration file and is used as the base for files with a relative path (eg. the private keys for the SFTP server, the SQLite database if you use SQLite as data provider). The default value is "."
+- `--config-dir` string. Location of the config dir. This directory should contain the `sftpgo.conf` configuration file and is used as the base for files with a relative path (eg. the private keys for the SFTP server, the SQLite database if you use SQLite as data provider). The default value is "." or the value of `SFTPGO_CONFIG_DIR` environment variable
-- `--log-file-path` string. Location for the log file, default "sftpgo.log"
+- `--config-file-name` string. Name of the configuration file. It must be the name of a file stored in config-dir not the absolute path to the configuration file. The default value is "sftpgo.conf" or the value of `SFTPGO_CONFIG_FILE_NAME` environment variable
-- `--log-max-size` int. Maximum size in megabytes of the log file before it gets rotated. Default 10
+- `--log-file-path` string. Location for the log file, default "sftpgo.log" or the value of `SFTPGO_LOG_FILE_PATH` environment variable
-- `--log-max-backups` int. Maximum number of old log files to retain. Default 5
+- `--log-max-size` int. Maximum size in megabytes of the log file before it gets rotated. Default 10 or the value of `SFTPGO_LOG_MAX_SIZE` environment variable
-- `--log-max-age` int. Maximum number of days to retain old log files. Default 28
+- `--log-max-backups` int. Maximum number of old log files to retain. Default 5 or the value of `SFTPGO_LOG_MAX_BACKUPS` environment variable
-- `--log-compress` boolean. Determine if the rotated log files should be compressed using gzip
+- `--log-max-age` int. Maximum number of days to retain old log files. Default 28 or the value of `SFTPGO_LOG_MAX_AGE` environment variable
-- `--log-verbose` boolean. Enable verbose logs. Default `true`
+- `--log-compress` boolean. Determine if the rotated log files should be compressed using gzip. Default `false` or the integer value of `SFTPGO_LOG_COMPRESS` environment variable (> 0 is `true`, 0 or invalid integer is `false`)
+- `--log-verbose` boolean. Enable verbose logs. Default `true` or the integer value of `SFTPGO_LOG_VERBOSE` environment variable (> 0 is `true`, 0 or invalid integer is `false`)
 
 If you don't configure any private host keys, the daemon will use `id_rsa` in the configuration directory. If that file doesn't exist, the daemon will attempt to autogenerate it (if the user that executes SFTPGo has write access to the config-dir). The server supports any private key format supported by [`crypto/ssh`](https://github.com/golang/crypto/blob/master/ssh/keys.go#L32).
 

main.go

@@ -20,15 +20,16 @@ import (
 	"github.com/drakkan/sftpgo/dataprovider"
 	"github.com/drakkan/sftpgo/logger"
 	"github.com/drakkan/sftpgo/sftpd"
+	"github.com/drakkan/sftpgo/utils"
 
 	"github.com/rs/zerolog"
 )
 
 func main() {
-	confName := "sftpgo.conf"
 	logSender := "main"
 	var (
 		configDir      string
+		configFileName string
 		logFilePath    string
 		logMaxSize     int
 		logMaxBackups  int
@@ -36,17 +37,23 @@ func main() {
 		logCompress    bool
 		logVerbose     bool
 	)
-	flag.StringVar(&configDir, "config-dir", ".", "Location for SFTPGo config dir. It must contain sftpgo.conf "+
+	flag.StringVar(&configDir, "config-dir", utils.GetEnvVar("SFTPGO_CONFIG_DIR", "."), "Location for SFTPGo config dir. It must contain "+
-		"and is used as the base for files with a relative path (eg. the private keys for the SFTP server, the SQLite database if you use SQLite as data provider).")
+		"sftpgo.conf or the configured config-file-name and it is used as the base for files with a relative path (eg. the private "+
-	flag.StringVar(&logFilePath, "log-file-path", "sftpgo.log", "Location for the log file")
+		"keys for the SFTP server, the SQLite database if you use SQLite as data provider).")
-	flag.IntVar(&logMaxSize, "log-max-size", 10, "Maximum size in megabytes of the log file before it gets rotated.")
+	flag.StringVar(&configFileName, "config-file-name", utils.GetEnvVar("SFTPGO_CONFIG_FILE_NAME", "sftpgo.conf"), "Name for SFTPGo "+
-	flag.IntVar(&logMaxBackups, "log-max-backups", 5, "Maximum number of old log files to retain")
+		"configuration file. It must be the name of a file stored in config-dir not the absolute path to the configuration file")
-	flag.IntVar(&logMaxAge, "log-max-age", 28, "Maximum number of days to retain old log files")
+	flag.StringVar(&logFilePath, "log-file-path", utils.GetEnvVar("SFTPGO_LOG_FILE_PATH", "sftpgo.log"), "Location for the log file")
-	flag.BoolVar(&logCompress, "log-compress", false, "Determine if the rotated log files should be compressed using gzip")
+	flag.IntVar(&logMaxSize, "log-max-size", utils.GetEnvVarAsInt("SFTPGO_LOG_MAX_SIZE", 10), "Maximum size in megabytes of the log file "+
-	flag.BoolVar(&logVerbose, "log-verbose", true, "Enable verbose logs")
+		"before it gets rotated.")
+	flag.IntVar(&logMaxBackups, "log-max-backups", utils.GetEnvVarAsInt("SFTPGO_LOG_MAX_BACKUPS", 5), "Maximum number of old log files "+
+		"to retain")
+	flag.IntVar(&logMaxAge, "log-max-age", utils.GetEnvVarAsInt("SFTPGO_LOG_MAX_AGE", 28), "Maximum number of days to retain old log files")
+	flag.BoolVar(&logCompress, "log-compress", utils.GetEnvVarAsInt("SFTPGO_LOG_COMPRESS", 0) > 0, "Determine if the rotated log files "+
+		"should be compressed using gzip")
+	flag.BoolVar(&logVerbose, "log-verbose", utils.GetEnvVarAsInt("SFTPGO_LOG_VERBOSE", 1) > 0, "Enable verbose logs")
 	flag.Parse()
 
-	configFilePath := filepath.Join(configDir, confName)
+	configFilePath := filepath.Join(configDir, configFileName)
 	logLevel := zerolog.DebugLevel
 	if !logVerbose {
 		logLevel = zerolog.InfoLevel

utils/utils.go

@@ -5,6 +5,7 @@ import (
 	"os"
 	"path/filepath"
 	"runtime"
+	"strconv"
 	"time"
 
 	"github.com/drakkan/sftpgo/logger"
@@ -69,3 +70,23 @@ func SetPathPermissions(path string, uid int, gid int) {
 		}
 	}
 }
+
+// GetEnvVar retrieves the value of the environment variable named
+// by the key. If the variable is present in the environment the it
+// returns the fallback value
+func GetEnvVar(key, fallback string) string {
+	if value, ok := os.LookupEnv(key); ok {
+		return value
+	}
+	return fallback
+}
+
+// GetEnvVarAsInt retrieves the value of the environment variable named
+// by the key and returns its value or fallback
+func GetEnvVarAsInt(key string, fallback int) int {
+	stringValue := GetEnvVar(key, strconv.Itoa(fallback))
+	if value, err := strconv.Atoi(stringValue); err == nil {
+		return value
+	}
+	return fallback
+}