adding mechanism to override the smartctl commands used by scrutiny for device scanning, device identification and smart data retrieval.

adding tests for command overrides.

rename GetScanOverrides() to GetDeviceOverrides()

fixes #255

collector/pkg/config/testdata/invalid_commands_includes_device.yaml

@@ -0,0 +1,4 @@
+commands:
+  metrics_scan_args: '--scan --json' # used to detect devices
+  metrics_info_args: '--info --json --device=sat' # used to determine device unique ID & register device with Scrutiny
+  metrics_smart_args: '--xall --json -d sat' # used to retrieve smart data for each device.

collector/pkg/config/testdata/invalid_commands_missing_json.yaml

@@ -0,0 +1,4 @@
+commands:
+  metrics_scan_args: '--scan' # used to detect devices
+  metrics_info_args: '--info -j' # used to determine device unique ID & register device with Scrutiny
+  metrics_smart_args: '--xall --json' # used to retrieve smart data for each device.

collector/pkg/config/testdata/override_commands.yaml

@@ -0,0 +1,4 @@
+commands:
+  metrics_scan_args: '--scan --json' # used to detect devices
+  metrics_info_args: '--info -j' # used to determine device unique ID & register device with Scrutiny
+  metrics_smart_args: '--xall --json -T permissive' # used to retrieve smart data for each device.

collector/pkg/config/testdata/override_device_commands.yaml

@@ -0,0 +1,5 @@
+version: 1
+devices:
+  - device: /dev/sda
+    commands:
+      metrics_info_args: "--info --json -T permissive"