Remove embedded interfaces from structs (#104)

The `db` struct doesn't need to embed the `Database` interface. Instead
we can verify that it satisfies the interface which would detect when
the definition of the interface changes (new method for instance).

The change has also been applied to the other structs following the same
pattern.

Signed-off-by: Simon Pasquier <[email protected]>

Author: simonpasquier

database/database.go

@@ -71,7 +71,6 @@ func New(cfg config.Database) Database {
 }
 
 type db struct {
-	Database
 	// metrics is the list of metric name (as a key) associated with their usage based on the different collector activated.
 	// This struct is our "database".
 	metrics map[string]*v1.Metric
@@ -115,6 +114,8 @@ type db struct {
 	partialMetricsUsageMutex sync.Mutex
 }
 
+var _ = Database(&db{})
+
 func (d *db) DeleteMetric(name string) bool {
 	d.metricsMutex.Lock()
 	defer d.metricsMutex.Unlock()

source/grafana/grafana.go

@@ -71,13 +71,14 @@ func NewCollector(db database.Database, cfg config.GrafanaCollector) (async.Simp
 }
 
 type grafanaCollector struct {
-	async.SimpleTask
 	metricUsageClient *usageclient.Client
 	grafanaURL        string
 	grafanaClient     *grafanaapi.GrafanaHTTPAPI
 	logger            *logrus.Entry
 }
 
+var _ async.SimpleTask = &grafanaCollector{}
+
 func (c *grafanaCollector) Execute(ctx context.Context, _ context.CancelFunc) error {
 	hits, err := c.collectAllDashboardUID(ctx)
 	if err != nil {

source/labels/labels.go

@@ -51,7 +51,6 @@ func NewCollector(db database.Database, cfg *config.LabelsCollector) (async.Simp
 }
 
 type labelCollector struct {
-	async.SimpleTask
 	promClient        v1.API
 	db                database.Database
 	metricUsageClient client.Client
@@ -60,6 +59,8 @@ type labelCollector struct {
 	logger            *logrus.Entry
 }
 
+var _ async.SimpleTask = &labelCollector{}
+
 func (c *labelCollector) Execute(ctx context.Context, _ context.CancelFunc) error {
 	now := time.Now()
 	start := now.Add(time.Duration(-c.period))

source/metric/metric.go

@@ -40,13 +40,14 @@ func NewCollector(db database.Database, cfg config.MetricCollector) (async.Simpl
 }
 
 type metricCollector struct {
-	async.SimpleTask
 	client v1.API
 	db     database.Database
 	period model.Duration
 	logger *logrus.Entry
 }
 
+var _ async.SimpleTask = &metricCollector{}
+
 func (c *metricCollector) Execute(ctx context.Context, _ context.CancelFunc) error {
 	now := time.Now()
 	start := now.Add(time.Duration(-c.period))

source/perses/perses.go

@@ -60,13 +60,14 @@ func NewCollector(db database.Database, cfg config.PersesCollector) (async.Simpl
 }
 
 type persesCollector struct {
-	async.SimpleTask
 	persesClient      persesClientV1.DashboardInterface
 	metricUsageClient *usageclient.Client
 	persesURL         string
 	logger            *logrus.Entry
 }
 
+var _ async.SimpleTask = &persesCollector{}
+
 func (c *persesCollector) Execute(_ context.Context, _ context.CancelFunc) error {
 	dashboards, err := c.persesClient.List("")
 	if err != nil {

source/rules/rules.go

@@ -62,14 +62,15 @@ func NewCollector(db database.Database, cfg *config.RulesCollector) (async.Simpl
 }
 
 type rulesCollector struct {
-	async.SimpleTask
 	promClient        v1.API
 	metricUsageClient *usageclient.Client
 	promURL           string
 	logger            *logrus.Entry
 	retry             uint
 }
 
+var _ async.SimpleTask = &rulesCollector{}
+
 func (c *rulesCollector) Execute(ctx context.Context, _ context.CancelFunc) error {
 	result, err := c.getRules(ctx)
 	if err != nil {