NOISSUE - Implement errors package in senml transformer, readers and writers (#1108)

* Implement errors package in senml transformer, readers and writers

Signed-off-by: Ivan Milošević <iva@blokovi.com>

* Remove unused const
Return wrapped error in postgres writer

Signed-off-by: Ivan Milošević <iva@blokovi.com>

* fix default db host in postgres writer

Signed-off-by: Ivan Milošević <iva@blokovi.com>

* fix capital letters in errors messages

Signed-off-by: Ivan Milošević <iva@blokovi.com>

* use svcName instead of postgres for Promethius initialization

Signed-off-by: Ivan Milošević <iva@blokovi.com>

cmd/postgres-reader/main.go

@@ -31,7 +31,7 @@ import (
 )
 
 const (
-	svcName = "postgres-writer"
+	svcName = "postgres-reader"
 	sep     = ","
 
 	defLogLevel          = "error"
@@ -112,7 +112,7 @@ func main() {
 	}()
 
 	err = <-errs
-	logger.Error(fmt.Sprintf("Postgres writer service terminated: %s", err))
+	logger.Error(fmt.Sprintf("Postgres reader service terminated: %s", err))
 }
 
 func loadConfig() config {
@@ -213,14 +213,14 @@ func newService(db *sqlx.DB, logger logger.Logger) readers.MessageRepository {
 	svc = api.MetricsMiddleware(
 		svc,
 		kitprometheus.NewCounterFrom(stdprometheus.CounterOpts{
-			Namespace: "postgres",
+			Namespace: svcName,
-			Subsystem: "message_writer",
+			Subsystem: "message_reader",
 			Name:      "request_count",
 			Help:      "Number of requests received.",
 		}, []string{"method"}),
 		kitprometheus.NewSummaryFrom(stdprometheus.SummaryOpts{
-			Namespace: "postgres",
+			Namespace: svcName,
-			Subsystem: "message_writer",
+			Subsystem: "message_reader",
 			Name:      "request_latency_microseconds",
 			Help:      "Total duration of requests in microseconds.",
 		}, []string{"method"}),

cmd/postgres-writer/main.go

@@ -30,7 +30,7 @@ const (
 	defLogLevel        = "error"
 	defNatsURL         = "nats://localhost:4222"
 	defPort            = "8180"
-	defDBHost          = "postgres"
+	defDBHost          = "localhost"
 	defDBPort          = "5432"
 	defDBUser          = "mainflux"
 	defDBPass          = "mainflux"
@@ -139,13 +139,13 @@ func newService(db *sqlx.DB, logger logger.Logger) writers.MessageRepository {
 	svc = api.MetricsMiddleware(
 		svc,
 		kitprometheus.NewCounterFrom(stdprometheus.CounterOpts{
-			Namespace: "postgres",
+			Namespace: svcName,
 			Subsystem: "message_writer",
 			Name:      "request_count",
 			Help:      "Number of requests received.",
 		}, []string{"method"}),
 		kitprometheus.NewSummaryFrom(stdprometheus.SummaryOpts{
-			Namespace: "postgres",
+			Namespace: svcName,
 			Subsystem: "message_writer",
 			Name:      "request_latency_microseconds",
 			Help:      "Total duration of requests in microseconds.",

readers/api/responses.go

@@ -30,3 +30,7 @@ func (res pageRes) Code() int {
 func (res pageRes) Empty() bool {
 	return false
 }
+
+type errorRes struct {
+	Err string `json:"error"`
+}

readers/api/transport.go

@@ -6,7 +6,6 @@ package api
 import (
 	"context"
 	"encoding/json"
-	"errors"
 	"net/http"
 	"strconv"
 	"time"
@@ -14,6 +13,7 @@ import (
 	kithttp "github.com/go-kit/kit/transport/http"
 	"github.com/go-zoo/bone"
 	"github.com/mainflux/mainflux"
+	"github.com/mainflux/mainflux/errors"
 	"github.com/mainflux/mainflux/readers"
 	"github.com/prometheus/client_golang/prometheus/promhttp"
 	"google.golang.org/grpc/codes"
@@ -111,15 +111,22 @@ func encodeResponse(_ context.Context, w http.ResponseWriter, response interface
 }
 
 func encodeError(_ context.Context, err error, w http.ResponseWriter) {
-	switch err {
+	switch {
-	case nil:
+	case errors.Contains(err, nil):
-	case errInvalidRequest:
+	case errors.Contains(err, errInvalidRequest):
 		w.WriteHeader(http.StatusBadRequest)
-	case errUnauthorizedAccess:
+	case errors.Contains(err, errUnauthorizedAccess):
 		w.WriteHeader(http.StatusForbidden)
 	default:
 		w.WriteHeader(http.StatusInternalServerError)
 	}
+	errorVal, ok := err.(errors.Error)
+	if ok {
+		w.Header().Set("Content-Type", contentType)
+		if err := json.NewEncoder(w).Encode(errorRes{Err: errorVal.Msg()}); err != nil {
+			w.WriteHeader(http.StatusInternalServerError)
+		}
+	}
 }
 
 func authorize(r *http.Request, chanID string) error {

readers/cassandra/messages.go

@@ -7,10 +7,13 @@ import (
 	"fmt"
 
 	"github.com/gocql/gocql"
+	"github.com/mainflux/mainflux/errors"
 	"github.com/mainflux/mainflux/readers"
 	"github.com/mainflux/mainflux/transformers/senml"
 )
 
+var errReadMessages = errors.New("faled to read messages from cassandra database")
+
 var _ readers.MessageRepository = (*cassandraRepository)(nil)
 
 type cassandraRepository struct {
@@ -59,13 +62,13 @@ func (cr cassandraRepository) ReadAll(chanID string, offset, limit uint64, query
 			&msg.Name, &msg.Unit, &msg.Value, &msg.StringValue, &msg.BoolValue,
 			&msg.DataValue, &msg.Sum, &msg.Time, &msg.UpdateTime)
 		if err != nil {
-			return readers.MessagesPage{}, err
+			return readers.MessagesPage{}, errors.Wrap(errReadMessages, err)
 		}
 		page.Messages = append(page.Messages, msg)
 	}
 
 	if err := cr.session.Query(countCQL, vals[:len(vals)-1]...).Scan(&page.Total); err != nil {
-		return readers.MessagesPage{}, err
+		return readers.MessagesPage{}, errors.Wrap(errReadMessages, err)
 	}
 
 	return page, nil

readers/influxdb/messages.go

@@ -8,6 +8,7 @@ import (
 	"strings"
 	"time"
 
+	"github.com/mainflux/mainflux/errors"
 	"github.com/mainflux/mainflux/readers"
 
 	influxdata "github.com/influxdata/influxdb/client/v2"
@@ -16,6 +17,8 @@ import (
 
 const countCol = "count"
 
+var errReadMessages = errors.New("faled to read messages from influxdb database")
+
 var _ readers.MessageRepository = (*influxRepository)(nil)
 
 type influxRepository struct {
@@ -43,10 +46,10 @@ func (repo *influxRepository) ReadAll(chanID string, offset, limit uint64, query
 
 	resp, err := repo.client.Query(q)
 	if err != nil {
-		return readers.MessagesPage{}, err
+		return readers.MessagesPage{}, errors.Wrap(errReadMessages, err)
 	}
 	if resp.Error() != nil {
-		return readers.MessagesPage{}, resp.Error()
+		return readers.MessagesPage{}, errors.Wrap(errReadMessages, resp.Error())
 	}
 
 	if len(resp.Results) < 1 || len(resp.Results[0].Series) < 1 {
@@ -60,7 +63,7 @@ func (repo *influxRepository) ReadAll(chanID string, offset, limit uint64, query
 
 	total, err := repo.count(condition)
 	if err != nil {
-		return readers.MessagesPage{}, err
+		return readers.MessagesPage{}, errors.Wrap(errReadMessages, err)
 	}
 
 	return readers.MessagesPage{

readers/mongodb/messages.go

@@ -6,6 +6,7 @@ package mongodb
 import (
 	"context"
 
+	"github.com/mainflux/mainflux/errors"
 	"github.com/mainflux/mainflux/readers"
 	"github.com/mainflux/mainflux/transformers/senml"
 	"go.mongodb.org/mongo-driver/bson"
@@ -15,6 +16,8 @@ import (
 
 const collection = "mainflux"
 
+var errReadMessages = errors.New("faled to read messages from mongodb database")
+
 var _ readers.MessageRepository = (*mongoRepository)(nil)
 
 type mongoRepository struct {
@@ -54,7 +57,7 @@ func (repo mongoRepository) ReadAll(chanID string, offset, limit uint64, query m
 	filter := fmtCondition(chanID, query)
 	cursor, err := col.Find(context.Background(), filter, options.Find().SetSort(sortMap).SetLimit(int64(limit)).SetSkip(int64(offset)))
 	if err != nil {
-		return readers.MessagesPage{}, err
+		return readers.MessagesPage{}, errors.Wrap(errReadMessages, err)
 	}
 	defer cursor.Close(context.Background())
 
@@ -62,7 +65,7 @@ func (repo mongoRepository) ReadAll(chanID string, offset, limit uint64, query m
 	for cursor.Next(context.Background()) {
 		var m message
 		if err := cursor.Decode(&m); err != nil {
-			return readers.MessagesPage{}, err
+			return readers.MessagesPage{}, errors.Wrap(errReadMessages, err)
 		}
 
 		msg := senml.Message{
@@ -93,7 +96,7 @@ func (repo mongoRepository) ReadAll(chanID string, offset, limit uint64, query m
 
 	total, err := col.CountDocuments(context.Background(), filter)
 	if err != nil {
-		return readers.MessagesPage{}, err
+		return readers.MessagesPage{}, errors.Wrap(errReadMessages, err)
 	}
 	if total < 0 {
 		return readers.MessagesPage{}, nil

readers/postgres/messages.go

@@ -4,17 +4,17 @@
 package postgres
 
 import (
-	"errors"
 	"fmt"
 
 	"github.com/jmoiron/sqlx" // required for DB access
+	"github.com/mainflux/mainflux/errors"
 	"github.com/mainflux/mainflux/readers"
 	"github.com/mainflux/mainflux/transformers/senml"
 )
 
 const errInvalid = "invalid_text_representation"
 
-var errInvalidMessage = errors.New("invalid message representation")
+var errReadMessages = errors.New("faled to read messages from postgres database")
 
 var _ readers.MessageRepository = (*postgresRepository)(nil)
 
@@ -46,7 +46,7 @@ func (tr postgresRepository) ReadAll(chanID string, offset, limit uint64, query
 
 	rows, err := tr.db.NamedQuery(q, params)
 	if err != nil {
-		return readers.MessagesPage{}, err
+		return readers.MessagesPage{}, errors.Wrap(errReadMessages, err)
 	}
 	defer rows.Close()
 
@@ -58,7 +58,7 @@ func (tr postgresRepository) ReadAll(chanID string, offset, limit uint64, query
 	for rows.Next() {
 		dbm := dbMessage{Channel: chanID}
 		if err := rows.StructScan(&dbm); err != nil {
-			return readers.MessagesPage{}, err
+			return readers.MessagesPage{}, errors.Wrap(errReadMessages, err)
 		}
 
 		msg := toMessage(dbm)
@@ -74,7 +74,7 @@ func (tr postgresRepository) ReadAll(chanID string, offset, limit uint64, query
 	}
 
 	if err := tr.db.QueryRow(q, qParams...).Scan(&page.Total); err != nil {
-		return readers.MessagesPage{}, err
+		return readers.MessagesPage{}, errors.Wrap(errReadMessages, err)
 	}
 
 	return page, nil

transformers/senml/transformer.go

@@ -5,10 +5,16 @@ package senml
 
 import (
 	"github.com/mainflux/mainflux/broker"
+	"github.com/mainflux/mainflux/errors"
 	"github.com/mainflux/mainflux/transformers"
 	"github.com/mainflux/senml"
 )
 
+var (
+	errDecode    = errors.New("failed to decode senml")
+	errNormalize = errors.New("faled to normalize senml")
+)
+
 var formats = map[string]senml.Format{
 	JSON: senml.JSON,
 	CBOR: senml.CBOR,
@@ -29,12 +35,12 @@ func (n transformer) Transform(msg broker.Message) (interface{}, error) {
 
 	raw, err := senml.Decode(msg.Payload, format)
 	if err != nil {
-		return nil, err
+		return nil, errors.Wrap(errDecode, err)
 	}
 
 	normalized, err := senml.Normalize(raw)
 	if err != nil {
-		return nil, err
+		return nil, errors.Wrap(errNormalize, err)
 	}
 
 	msgs := make([]Message, len(normalized.Records))

transformers/senml/transformer_test.go

@@ -9,6 +9,7 @@ import (
 	"testing"
 
 	"github.com/mainflux/mainflux/broker"
+	"github.com/mainflux/mainflux/errors"
 	"github.com/mainflux/mainflux/transformers/senml"
 	mfsenml "github.com/mainflux/senml"
 	"github.com/stretchr/testify/assert"
@@ -102,6 +103,6 @@ func TestTransform(t *testing.T) {
 	for _, tc := range cases {
 		msgs, err := tr.Transform(tc.msg)
 		assert.Equal(t, tc.msgs, msgs, fmt.Sprintf("%s expected %v, got %v", tc.desc, tc.msgs, msgs))
-		assert.Equal(t, tc.err, err, fmt.Sprintf("%s expected %s, got %s", tc.desc, tc.err, err))
+		assert.True(t, errors.Contains(err, tc.err), fmt.Sprintf("%s expected %s, got %s", tc.desc, tc.err, err))
 	}
 }

writers/cassandra/messages.go

@@ -5,10 +5,13 @@ package cassandra
 
 import (
 	"github.com/gocql/gocql"
+	"github.com/mainflux/mainflux/errors"
 	"github.com/mainflux/mainflux/transformers/senml"
 	"github.com/mainflux/mainflux/writers"
 )
 
+var errSaveMessage = errors.New("faled to save message to cassandra database")
+
 var _ writers.MessageRepository = (*cassandraRepository)(nil)
 
 type cassandraRepository struct {
@@ -32,7 +35,7 @@ func (cr *cassandraRepository) Save(messages ...senml.Message) error {
 			msg.Protocol, msg.Name, msg.Unit, msg.Value, msg.StringValue,
 			msg.BoolValue, msg.DataValue, msg.Sum, msg.Time, msg.UpdateTime).Exec()
 		if err != nil {
-			return err
+			return errors.Wrap(errSaveMessage, err)
 		}
 	}
 

writers/influxdb/messages.go

@@ -8,6 +8,7 @@ import (
 	"strconv"
 	"time"
 
+	"github.com/mainflux/mainflux/errors"
 	"github.com/mainflux/mainflux/transformers/senml"
 	"github.com/mainflux/mainflux/writers"
 
@@ -16,6 +17,8 @@ import (
 
 const pointName = "messages"
 
+var errSaveMessage = errors.New("faled to save message to influxdb database")
+
 var _ writers.MessageRepository = (*influxRepo)(nil)
 
 type influxRepo struct {
@@ -39,7 +42,7 @@ func New(client influxdata.Client, database string) writers.MessageRepository {
 func (repo *influxRepo) Save(messages ...senml.Message) error {
 	pts, err := influxdata.NewBatchPoints(repo.cfg)
 	if err != nil {
-		return err
+		return errors.Wrap(errSaveMessage, err)
 	}
 
 	for _, msg := range messages {
@@ -50,12 +53,14 @@ func (repo *influxRepo) Save(messages ...senml.Message) error {
 
 		pt, err := influxdata.NewPoint(pointName, tgs, flds, t)
 		if err != nil {
-			return err
+			return errors.Wrap(errSaveMessage, err)
 		}
 		pts.AddPoint(pt)
 	}
-
+	if err := repo.client.Write(pts); err != nil {
-	return repo.client.Write(pts)
+		return errors.Wrap(errSaveMessage, err)
+	}
+	return nil
 }
 
 func (repo *influxRepo) tagsOf(msg *senml.Message) tags {

writers/mongodb/messages.go

@@ -8,12 +8,15 @@ import (
 
 	"go.mongodb.org/mongo-driver/mongo"
 
+	"github.com/mainflux/mainflux/errors"
 	"github.com/mainflux/mainflux/transformers/senml"
 	"github.com/mainflux/mainflux/writers"
 )
 
 const collectionName string = "mainflux"
 
+var errSaveMessage = errors.New("faled to save message to mongodb database")
+
 var _ writers.MessageRepository = (*mongoRepo)(nil)
 
 type mongoRepo struct {
@@ -73,5 +76,8 @@ func (repo *mongoRepo) Save(messages ...senml.Message) error {
 	}
 
 	_, err := coll.InsertMany(context.Background(), msgs)
-	return err
+	if err != nil {
+		return errors.Wrap(errSaveMessage, err)
+	}
+	return nil
 }

writers/postgres/messages.go

@@ -5,21 +5,23 @@ package postgres
 
 import (
 	"context"
-	"errors"
 
 	"github.com/gofrs/uuid"
-
 	"github.com/jmoiron/sqlx"
 	"github.com/lib/pq" // required for DB access
+	"github.com/mainflux/mainflux/errors"
 	"github.com/mainflux/mainflux/transformers/senml"
 	"github.com/mainflux/mainflux/writers"
 )
 
 const errInvalid = "invalid_text_representation"
 
-// ErrInvalidMessage indicates that service received message that
+var (
-// doesn't fit required format.
+	// ErrInvalidMessage indicates that service received message that
-var ErrInvalidMessage = errors.New("invalid message representation")
+	// doesn't fit required format.
+	ErrInvalidMessage = errors.New("invalid message representation")
+	errSaveMessage    = errors.New("faled to save message to postgress database")
+)
 
 var _ writers.MessageRepository = (*postgresRepo)(nil)
 
@@ -42,13 +44,13 @@ func (pr postgresRepo) Save(messages ...senml.Message) error {
 
 	tx, err := pr.db.BeginTxx(context.Background(), nil)
 	if err != nil {
-		return err
+		return errors.Wrap(errSaveMessage, err)
 	}
 
 	for _, msg := range messages {
 		dbth, err := toDBMessage(msg)
 		if err != nil {
-			return err
+			return errors.Wrap(errSaveMessage, err)
 		}
 
 		if _, err := tx.NamedExec(q, dbth); err != nil {
@@ -56,15 +58,17 @@ func (pr postgresRepo) Save(messages ...senml.Message) error {
 			if ok {
 				switch pqErr.Code.Name() {
 				case errInvalid:
-					return ErrInvalidMessage
+					return errors.Wrap(errSaveMessage, ErrInvalidMessage)
 				}
 			}
 
-			return err
+			return errors.Wrap(errSaveMessage, err)
 		}
 	}
-
+	if err := tx.Commit(); err != nil {
-	return tx.Commit()
+		return errors.Wrap(errSaveMessage, err)
+	}
+	return nil
 }
 
 type dbMessage struct {