Fix comments

Author: niksajakovljevic

main.go

@@ -113,7 +113,7 @@ func main() {
 	http.Handle(cfg.telemetryPath, prometheus.Handler())
 
 	writer, reader := buildClients(cfg)
-	election = initElection(cfg, writer.(*pgprometheus.Client).Db)
+	election = initElection(cfg, writer.(*pgprometheus.Client).DB)
 
 	http.Handle("/write", timeHandler("write", write(writer)))
 	http.Handle("/read", timeHandler("read", read(reader)))

postgresql/client.go

@@ -64,7 +64,7 @@ func ParseFlags(cfg *Config) *Config {
 
 // Client sends Prometheus samples to PostgreSQL
 type Client struct {
-	Db  *sql.DB
+	DB  *sql.DB
 	cfg *Config
 }
 
@@ -101,7 +101,7 @@ func NewClient(cfg *Config) *Client {
 	db.SetMaxIdleConns(cfg.maxIdleConns)
 
 	client := &Client{
-		Db:  db,
+		DB:  db,
 		cfg: cfg,
 	}
 
@@ -121,7 +121,7 @@ func NewClient(cfg *Config) *Client {
 }
 
 func (c *Client) setupPgPrometheus() error {
-	tx, err := c.Db.Begin()
+	tx, err := c.DB.Begin()
 
 	if err != nil {
 		return err
@@ -193,7 +193,7 @@ func metricString(m model.Metric) string {
 // Write implements the Writer interface and writes metric samples to the database
 func (c *Client) Write(samples model.Samples) error {
 	begin := time.Now()
-	tx, err := c.Db.Begin()
+	tx, err := c.DB.Begin()
 
 	if err != nil {
 		log.Error("msg", "Error on Begin when writing samples", "err", err)
@@ -360,7 +360,7 @@ func (c *Client) Read(req *prompb.ReadRequest) (*prompb.ReadResponse, error) {
 
 		log.Debug("msg", "Executed query", "query", command)
 
-		rows, err := c.Db.Query(command)
+		rows, err := c.DB.Query(command)
 
 		if err != nil {
 			return nil, err
@@ -439,7 +439,7 @@ func (c *Client) Read(req *prompb.ReadRequest) (*prompb.ReadResponse, error) {
 
 // HealthCheck implements the healtcheck interface
 func (c *Client) HealthCheck() error {
-	rows, err := c.Db.Query("SELECT 1")
+	rows, err := c.DB.Query("SELECT 1")
 
 	if err != nil {
 		log.Debug("msg", "Health check error", "err", err)

util/election.go

@@ -1,5 +1,6 @@
 package util
 
+// Election defines an interface for adapter leader election.
 // If you are running Prometheus in HA mode where each Prometheus instance sends data to corresponding adapter you probably
 // want to allow writes into the database from only one adapter at the time. We need to elect a leader who can write to
 // the database. If leader goes down, another leader is elected. Look at `lock.go` for an implementation based on PostgreSQL

util/lock.go

@@ -14,7 +14,7 @@ const (
 	connCheckInterval = time.Millisecond * 250
 )
 
-// One implementation of leader election protocol based on PostgreSQL advisory locks. All adapters withing a HA group are trying
+// PgAdvisoryLock is implementation of leader election protocol based on PostgreSQL advisory locks. All adapters withing a HA group are trying
 // to obtain an advisory lock for particular group. The one who holds the lock can write to the database. Due to the fact
 // that Prometheus HA setup provides no consistency guarantees this implementation is best effort in regards
 // to metrics that is written (some duplicates or data loss are possible during failover)