Update logfile documentation

docs/CONFIGURATION.md

@@ -136,19 +136,25 @@ The agent table configures Telegraf and the defaults used across all plugins.
   service input to set the timestamp at the appropriate precision.
 
 - **debug**:
-  Run telegraf with debug log messages.
+  Log at debug level.
+
 - **quiet**:
-  Run telegraf in quiet mode (error log messages only).
+  Log only error level messages.
+
 - **logfile**:
-  Specify the log file name. The empty string means to log to stderr.
+  Log file name, the empty string means to log to stderr.
+
 - **logfile_rotation_interval**:
-  Log file rotation time [interval][], e.g. "1d" means logs will rotated every day. Default is 0 => no rotation based on time.
+  The logfile will be rotated after the time interval specified.  When set to
+  0 no time based rotation is performed.
+
 - **logfile_rotation_max_size**:
-  The log file max [size][]. Log files will be rotated when they exceed this size. Default is 0 => no rotation based on file size.
+  The logfile will be rotated when it becomes larger than the specified size.
+  When set to 0 no size based rotation is performed.
+
 - **logfile_rotation_max_archives**:
-  Maximum number of archives (rotated) files to keep. Older log files are deleted first.
+  Maximum number of rotated archives to keep, any older logs are deleted.  If
-  This setting is only applicable if `logfile_rotation_interval` and/or `logfile_rotation_max_size` settings have been specified (otherwise there is no rotation)
+  set to -1, no archives are removed.
-  Default is 0 => all rotated files are deleted. Use -1 to keep all archives.
 
 - **hostname**:
   Override default hostname, if empty use os.Hostname()

internal/config/config.go

@@ -75,6 +75,7 @@ func NewConfig() *Config {
 			Interval:                   internal.Duration{Duration: 10 * time.Second},
 			RoundInterval:              true,
 			FlushInterval:              internal.Duration{Duration: 10 * time.Second},
+			LogfileRotationMaxArchives: 5,
 		},
 
 		Tags:          make(map[string]string),
@@ -140,22 +141,26 @@ type AgentConfig struct {
 	UTC bool `toml:"utc"`
 
 	// Debug is the option for running in debug mode
-	Debug bool
+	Debug bool `toml:"debug"`
-
-	// Logfile specifies the file to send logs to
-	Logfile string
-
-	// The log file rotation interval
-	LogfileRotationInterval internal.Duration
-
-	// The log file max size. Logs will rotated when they exceed this size.
-	LogfileRotationMaxSize internal.Size
-
-	// The max number of log archives to keep
-	LogfileRotationMaxArchives int
 
 	// Quiet is the option for running in quiet mode
-	Quiet        bool
+	Quiet bool `toml:"quiet"`
+
+	// Log file name, the empty string means to log to stderr.
+	Logfile string `toml:"logfile"`
+
+	// The logfile will be rotated when it becomes larger than the specified
+	// size.  When set to 0 no size based rotation is performed.
+	LogfileRotationInterval internal.Duration `toml:"logfile_rotation_interval"`
+
+	// Maximum number of rotated archives to keep, any older logs are deleted.
+	// If set to -1, no archives are removed.
+	LogfileRotationMaxSize internal.Size `toml:"logfile_rotation_max_size"`
+
+	// Maximum number of rotated archives to keep, any older logs are deleted.
+	// If set to -1, no archives are removed.
+	LogfileRotationMaxArchives int `toml:"logfile_rotation_max_archives"`
+
 	Hostname     string
 	OmitHostname bool
 }
@@ -275,24 +280,25 @@ var agentConfig = `
   ## Valid time units are "ns", "us" (or "µs"), "ms", "s".
   precision = ""
 
-  ## Logging configuration:
+  ## Log at debug level.
-  ## Run telegraf with debug log messages.
+  # debug = false
-  debug = false
+  ## Log only error level messages.
-  ## Run telegraf in quiet mode (error log messages only).
+  # quiet = false
-  quiet = false
+
-  ## Specify the log file name. The empty string means to log to stderr.
+  ## Log file name, the empty string means to log to stderr.
-  logfile = ""
+  # logfile = ""
-  ## Rotation settings, only applicable when log file name is specified.
+
-  ## Log file rotation time interval, e.g. "1d" means logs will rotated every day. Default is 0 => no rotation based on time.
+  ## The logfile will be rotated after the time interval specified.  When set
-  # logfile_rotation_interval = "1d"
+  ## to 0 no time based rotation is performed.
-  ## The log file max size. Log files will be rotated when they exceed this size. Default is 0 => no rotation based on file size.
+  # logfile_rotation_interval = "0d"
-  # logfile_rotation_max_size = "10 MB"
+
-  ## Maximum number of archives (rotated) files to keep. Older log files are deleted first.
+  ## The logfile will be rotated when it becomes larger than the specified
-  ## This setting is only applicable if logfile_rotation_interval and/or logfile_rotation_max_size settings have been specified (otherwise there is no rotation)
+  ## size.  When set to 0 no size based rotation is performed.
-  ## Default is 0 => all rotated files are deleted. 
+  # logfile_rotation_max_size = "0MB"
-  ## Use -1 to keep all archives.
+
-  ## Analogous to logrotate "rotate" setting http://man7.org/linux/man-pages/man8/logrotate.8.html
+  ## Maximum number of rotated archives to keep, any older logs are deleted.
-  # logfile_rotation_max_archives = 0
+  ## If set to -1, no archives are removed.
+  # logfile_rotation_max_archives = 5
 
   ## Override default hostname, if empty use os.Hostname()
   hostname = ""