add SMART_DEVICES env var (#373, #1335)

also iterate through parsers to try to find a match if type is not defined.

agent/smart_test.go

@@ -165,6 +165,55 @@ func TestDevicesSnapshotReturnsCopy(t *testing.T) {
 	assert.Len(t, snapshot, 2)
 }
 
+func TestScanDevicesWithEnvOverride(t *testing.T) {
+	t.Setenv("SMART_DEVICES", "/dev/sda:sat, /dev/nvme0:nvme")
+
+	sm := &SmartManager{
+		SmartDataMap: make(map[string]*smart.SmartData),
+	}
+
+	err := sm.ScanDevices()
+	require.NoError(t, err)
+
+	require.Len(t, sm.SmartDevices, 2)
+	assert.Equal(t, "/dev/sda", sm.SmartDevices[0].Name)
+	assert.Equal(t, "sat", sm.SmartDevices[0].Type)
+	assert.Equal(t, "/dev/nvme0", sm.SmartDevices[1].Name)
+	assert.Equal(t, "nvme", sm.SmartDevices[1].Type)
+}
+
+func TestScanDevicesWithEnvOverrideInvalid(t *testing.T) {
+	t.Setenv("SMART_DEVICES", ":sat")
+
+	sm := &SmartManager{
+		SmartDataMap: make(map[string]*smart.SmartData),
+	}
+
+	err := sm.ScanDevices()
+	require.Error(t, err)
+}
+
+func TestScanDevicesWithEnvOverrideEmpty(t *testing.T) {
+	t.Setenv("SMART_DEVICES", "   ")
+
+	sm := &SmartManager{
+		SmartDataMap: make(map[string]*smart.SmartData),
+	}
+
+	err := sm.ScanDevices()
+	assert.ErrorIs(t, err, errNoValidSmartData)
+	assert.Empty(t, sm.SmartDevices)
+}
+
+func TestSmartctlArgsWithoutType(t *testing.T) {
+	device := &DeviceInfo{Name: "/dev/sda"}
+
+	sm := &SmartManager{}
+
+	args := sm.smartctlArgs(device, true)
+	assert.Equal(t, []string{"-aj", "-n", "standby", "/dev/sda"}, args)
+}
+
 func TestSmartctlArgs(t *testing.T) {
 	sm := &SmartManager{}