avoid usage of pkg/errors and support of Go 1.13 errors wrapping (#1)

* avoid usage of pkg/errors

* update go

go.mod

@@ -1,12 +1,11 @@
 module github.com/humans-net/pq
 
-go 1.12
+go 1.14
 
 require (
 	github.com/jackc/pgconn v1.7.0
 	github.com/jackc/pgx/v4 v4.9.0
 	github.com/opentracing/opentracing-go v1.1.0
-	github.com/pkg/errors v0.8.1
 	github.com/prometheus/client_golang v1.1.0
 	go.uber.org/zap v1.10.0
 )

pgx_adapter.go

@@ -9,7 +9,6 @@ import (
 	"github.com/jackc/pgx/v4"
 	"github.com/jackc/pgx/v4/log/zapadapter"
 	"github.com/jackc/pgx/v4/pgxpool"
-	"github.com/pkg/errors"
 )
 
 type PgxAdapter struct {
@@ -19,12 +18,12 @@ type PgxAdapter struct {
 	name        string
 }
 
-var _ Client = &PgxAdapter{}
+var _ Client = (*PgxAdapter)(nil)
 
 func (p *PgxAdapter) Transaction(ctx context.Context, f func(context.Context, Executor) error) error {
-	tx, er := p.pool.BeginTx(ctx, defaultTxOptions)
-	if er != nil {
-		return er
+	tx, err := p.pool.BeginTx(ctx, defaultTxOptions)
+	if err != nil {
+		return fmt.Errorf("begin transaction: %w", err)
 	}
 
 	var txAdapter Executor = &PgxTxAdapter{tx}
@@ -34,20 +33,19 @@ func (p *PgxAdapter) Transaction(ctx context.Context, f func(context.Context, Ex
 	if p.withMetrics {
 		txAdapter = &metricsAdapter{Executor: txAdapter, name: p.name}
 	}
-	execErr := f(ctx, txAdapter)
-	var err error
-
-	if execErr != nil {
-		err = errors.Wrap(execErr, "failed to exec transaction")
-		rbErr := tx.Rollback(ctx)
-		if rbErr != nil {
-			err = errors.Wrapf(err, "failed to rollback failed transaction: %v", rbErr)
+
+	if txErr := f(ctx, txAdapter); txErr != nil {
+		txErr = fmt.Errorf("exec transaction: %w", txErr)
+
+		if err := tx.Rollback(ctx); err != nil {
+			txErr = fmt.Errorf("%w: rollback: %v", txErr, err)
 		}
-		return err
+
+		return txErr
 	}
 
 	if err := tx.Commit(ctx); err != nil {
-		return errors.Wrap(err, "failed to commit transaction")
+		return fmt.Errorf("commit transaction: %w", err)
 	}
 
 	return nil
@@ -74,9 +72,7 @@ func NewClient(ctx context.Context, cfg Config) Client {
 
 	poolCfg, err := pgxpool.ParseConfig(cfg.ConnString)
 	if err != nil {
-		if err != nil {
-			panic(fmt.Sprintf("failed to connect to postgres %s: %v", cfg.ConnString, err))
-		}
+		panic(fmt.Errorf("connect to postgres %s: %v", cfg.ConnString, err))
 	}
 
 	if cfg.TCPKeepAlivePeriod == 0 {
@@ -98,11 +94,11 @@ func NewClient(ctx context.Context, cfg Config) Client {
 
 	connPool, err := pgxpool.ConnectConfig(ctx, poolCfg)
 	if err != nil {
-		panic(fmt.Sprintf("failed to connect to postgres %s: %v", cfg.ConnString, err))
+		panic(fmt.Errorf("connect to postgres %s: %v", cfg.ConnString, err))
 	}
 
 	if err := collector.register(cfg.Name, connPool); err != nil {
-		panic(fmt.Sprintf("failed to register dbx pool %q: %v", cfg.Name, err))
+		panic(fmt.Errorf("register dbx pool %q: %v", cfg.Name, err))
 	}
 
 	var adapter Client = &PgxAdapter{

pgx_tx_adapter.go

@@ -16,7 +16,7 @@ type PgxTxAdapter struct {
 	tx pgx.Tx
 }
 
-var _ Executor = &PgxTxAdapter{}
+var _ Executor = (*PgxTxAdapter)(nil)
 
 func (p *PgxTxAdapter) Exec(ctx context.Context, sql string, args ...interface{}) (result RowsAffected, err error) {
 	return p.tx.Exec(ctx, sql, args...)