MF-404 - InfluxDB batch size and timeout zero values (#411)

* Add zero value check for batch size and timeout

Signed-off-by: Dušan Borovčanin <dusan.borovcanin@mainflux.com>

* Update InfluxDB writer tests

Test creation of InfluxDB writer with invalid (zero) batch size and timeout.

Signed-off-by: Dušan Borovčanin <dusan.borovcanin@mainflux.com>

* Fix config load

Loading batch size and timeout from env variables were missing in loadConfigs method.

Signed-off-by: Dušan Borovčanin <dusan.borovcanin@mainflux.com>

cmd/influxdb-writer/main.go

@@ -128,14 +128,16 @@ func main() {
 
 func loadConfigs() (config, influxdata.HTTPConfig) {
 	cfg := config{
-		NatsURL:  mainflux.Env(envNatsURL, defNatsURL),
-		LogLevel: mainflux.Env(envLogLevel, defLogLevel),
-		Port:     mainflux.Env(envPort, defPort),
-		DBName:   mainflux.Env(envDBName, defDBName),
-		DBHost:   mainflux.Env(envDBHost, defDBHost),
-		DBPort:   mainflux.Env(envDBPort, defDBPort),
-		DBUser:   mainflux.Env(envDBUser, defDBUser),
-		DBPass:   mainflux.Env(envDBPass, defDBPass),
+		NatsURL:      mainflux.Env(envNatsURL, defNatsURL),
+		LogLevel:     mainflux.Env(envLogLevel, defLogLevel),
+		Port:         mainflux.Env(envPort, defPort),
+		BatchSize:    mainflux.Env(envBatchSize, defBatchSize),
+		BatchTimeout: mainflux.Env(envBatchTimeout, defBatchTimeout),
+		DBName:       mainflux.Env(envDBName, defDBName),
+		DBHost:       mainflux.Env(envDBHost, defDBHost),
+		DBPort:       mainflux.Env(envDBPort, defDBPort),
+		DBUser:       mainflux.Env(envDBUser, defDBUser),
+		DBPass:       mainflux.Env(envDBPass, defDBPass),
 	}
 
 	clientCfg := influxdata.HTTPConfig{

writers/influxdb/messages.go

@@ -8,6 +8,7 @@
 package influxdb
 
 import (
+	"errors"
 	"strconv"
 	"sync"
 	"time"
@@ -22,6 +23,11 @@ const pointName = "messages"
 
 var _ writers.MessageRepository = (*influxRepo)(nil)
 
+var (
+	errZeroValueSize    = errors.New("zero value batch size")
+	errZeroValueTimeout = errors.New("zero value batch timeout")
+)
+
 type influxRepo struct {
 	client    influxdata.Client
 	batch     []*influxdata.Point
@@ -36,6 +42,14 @@ type tags map[string]string
 
 // New returns new InfluxDB writer.
 func New(client influxdata.Client, database string, batchSize int, batchTimeout time.Duration) (writers.MessageRepository, error) {
+	if batchSize == 0 {
+		return &influxRepo{}, errZeroValueSize
+	}
+
+	if batchTimeout == 0 {
+		return &influxRepo{}, errZeroValueTimeout
+	}
+
 	repo := &influxRepo{
 		client: client,
 		cfg: influxdata.BatchPointsConfig{

writers/influxdb/messages_test.go

@@ -75,6 +75,37 @@ func queryDB(cmd string) ([][]interface{}, error) {
 	return response.Results[0].Series[0].Values, nil
 }
 
+func TestNewWriter(t *testing.T) {
+	client, err := influxdata.NewHTTPClient(clientCfg)
+	require.Nil(t, err, fmt.Sprintf("Creating new InfluxDB client expected to succeed: %s.\n", err))
+
+	cases := []struct {
+		desc         string
+		batchSize    int
+		err          error
+		batchTimeout time.Duration
+		errText      string
+	}{
+		{
+			desc:         "Create writer with zero value batch size",
+			batchSize:    0,
+			batchTimeout: time.Duration(5 * time.Second),
+			errText:      "zero value batch size",
+		},
+		{
+			desc:         "Create writer with zero value batch timeout",
+			batchSize:    5,
+			batchTimeout: time.Duration(0 * time.Second),
+			errText:      "zero value batch timeout",
+		},
+	}
+
+	for _, tc := range cases {
+		_, err := writer.New(client, testDB, tc.batchSize, tc.batchTimeout)
+		assert.Equal(t, tc.errText, err.Error(), fmt.Sprintf("%s expected to have error \"%s\", but got \"%s\"", tc.desc, tc.errText, err))
+	}
+}
+
 func TestSave(t *testing.T) {
 	client, err := influxdata.NewHTTPClient(clientCfg)
 	require.Nil(t, err, fmt.Sprintf("Creating new InfluxDB client expected to succeed: %s.\n", err))