File backup reference guide (#107)

[#89] File backup reference guide

 - Provided the information relevant to available configurations per a Kanto File Backup instance
 - Added an example of how to use this configuration
 - Added an example of a generic configuration

Signed-off-by: Velitchko Valkov <[email protected]>
Co-authored-by: Evgeni Grigorov <[email protected]>

web/site/content/docs/references/file-backup-config.md

@@ -0,0 +1,103 @@
+---
+title: "File backup configuration"
+type: docs
+description: >
+  Customize the files backup and restore to and from a backend storage.
+weight: 6
+---
+
+### Properties
+
+To control all aspects of the file backup behavior.
+
+| Property | Type | Default | Description |
+| - | - | - | - |
+| featureId | string | BackupAndRestore | Feature unique identifier in the scope of the edge digital twin |
+| type | string | file | Type of the files that are backed up by this feature |
+| context | string | edge | Context of the files backed up by this feature, unique in the scope of the `type` |
+| dir | string | | Directory to be backed up |
+| mode | string | strict | Restriction on directories that can be dynamically selected for a backup, the supported modes are: strict, lax and scoped |
+| backupCmd | string | | Command to be executed before the backup is done |
+| restoreCmd | string | | Command to be executed after the restore |
+| singleUpload | bool | false | Forbid triggering of new backups when there is a backup in progress |
+| checksum | bool | false | Send MD5 checksum for backed up files to ensure data integrity |
+| stopTimeout | string | 30s | Time to wait for running backups to finish as a sequence of decimal numbers, each with optional fraction and a unit suffix, such as: 300ms, 1.5h, 10m30s, etc., time units are: ns, us (or µs), ms, s, m, h |
+| keepUploaded | bool | false | Keep successfully uploaded backups locally |
+| storage | string | ./storage | Directory where backups and downloads will be stored |
+| **Upload/Download - TLS** | | | |
+| serverCert| string | | PEM encoded certificate file for secure uploads and downloads |
+| **Auto backup** | | | |
+| active | bool | false | Activate periodic backups |
+| activeFrom | string | | Time from which periodic backups should be active, in RFC 3339 format, if omitted (and `active` flag is set) current time will be used as start of the periodic backups |
+| activeTill | string | | Time till which periodic backups should be active, in RFC 3339 format, if omitted (and `active` flag is set) periodic backups will be active indefinitely |
+| period | string | 10h| Backup period as a sequence of decimal numbers, each with optional fraction and a unit suffix, such as: 300ms, 1.5h, 10m30s, etc., time units are: ns, us (or µs), ms, s, m, h |
+| **Local connectivity** | | | |
+| broker | string | tcp://localhost:1883 | Address of the MQTT server/broker that the file backup will connect for the local communication, the format is: `scheme://host:port` |
+| username | string | | Username that is a part of the credentials |
+| password | string | | Password that is a part of the credentials |
+| **Local connectivity - TLS** | | | |
+| caCert | string | | PEM encoded CA certificates file |
+| cert | string | | PEM encoded certificate file to authenticate to the MQTT server/broker |
+| key | string | | PEM encoded unencrypted private key file to authenticate to the MQTT server/broker |
+| **Logging** | | | |
+| logFile | string | log/file-backup.log | Path to the file where log messages are written |
+| logLevel | string | INFO | All log messages at this or a higher level will be logged, the log levels in descending order are: ERROR, WARN, INFO, DEBUG and TRACE |
+| logFileCount | int | 5 | Log file maximum rotations count |
+| logFileMaxAge | int | 28 | Log file rotations maximum age in days, use 0 to not remove old log files |
+| logFileSize | int | 2 | Log file size in MB before it gets rotated |
+
+### Example
+
+The minimal required configuration that enables backing up a directory and sets the file type to config.
+
+```json
+{
+    "type": "config",
+    "dir": "/var/tmp/file-backup",
+    "mode": "scoped",
+    "storage": "/var/lib/file-backup",
+    "logFile": "/var/log/file-backup/file-backup.log"
+}
+```
+
+### Template
+
+The configuration can be further adjusted according to the use case.
+The following template illustrates all possible properties with their default values.
+
+{{% warn %}}
+Be aware that some combinations may be incompatible.
+{{% /warn %}}
+
+```json
+{
+  "featureId": "BackupAndRestore",
+  "type": "file",
+  "context": "edge",
+  "dir": "",
+  "mode": "strict",
+  "backupCmd": "",
+  "restoreCmd": "",
+  "singleUpload": false,
+  "checksum": false,
+  "stopTimeout": "30s",
+  "keepUploaded": false,
+  "storage": "./storage",
+  "serverCert": "",
+  "active": false,
+  "activeFrom": "",
+  "activeTill": "",
+  "period": "10h",
+  "broker": "tcp://localhost:1883",
+  "username": "",
+  "password": "",
+  "caCert": "",
+  "cert": "",
+  "key": "",
+  "logFile": "log/file-backup.log",
+  "logLevel": "INFO",
+  "logFileCount": 5,
+  "logFileMaxAge": 28,
+  "logFileSize": 2
+}
+```

web/site/content/docs/references/system-metrics-config.md

@@ -3,7 +3,7 @@ title: "System metrics configuration"
 type: docs
 description: >
   Customize the reporting of system metrics.
-weight: 6
+weight: 7
 ---
 
 ### Properties