Use persistent connection to postgresql database (#2701)

plugins/inputs/postgresql/postgresql_test.go

@@ -15,19 +15,18 @@ func TestPostgresqlGeneratesMetrics(t *testing.T) {
 	}
 
 	p := &Postgresql{
-		Address: fmt.Sprintf("host=%s user=postgres sslmode=disable",
-			testutil.GetLocalHost()),
+		Service: Service{
+			Address: fmt.Sprintf(
+				"host=%s user=postgres sslmode=disable",
+				testutil.GetLocalHost(),
+			),
+		},
 		Databases: []string{"postgres"},
 	}
 
 	var acc testutil.Accumulator
-	err := p.Gather(&acc)
-	require.NoError(t, err)
-
-	availableColumns := make(map[string]bool)
-	for _, col := range p.AllColumns {
-		availableColumns[col] = true
-	}
+	require.NoError(t, p.Start(&acc))
+	require.NoError(t, p.Gather(&acc))
 
 	intMetrics := []string{
 		"xact_commit",
@@ -71,39 +70,27 @@ func TestPostgresqlGeneratesMetrics(t *testing.T) {
 	metricsCounted := 0
 
 	for _, metric := range intMetrics {
-		_, ok := availableColumns[metric]
-		if ok {
-			assert.True(t, acc.HasInt64Field("postgresql", metric))
-			metricsCounted++
-		}
+		assert.True(t, acc.HasInt64Field("postgresql", metric))
+		metricsCounted++
 	}
 
 	for _, metric := range int32Metrics {
-		_, ok := availableColumns[metric]
-		if ok {
-			assert.True(t, acc.HasInt32Field("postgresql", metric))
-			metricsCounted++
-		}
+		assert.True(t, acc.HasInt32Field("postgresql", metric))
+		metricsCounted++
 	}
 
 	for _, metric := range floatMetrics {
-		_, ok := availableColumns[metric]
-		if ok {
-			assert.True(t, acc.HasFloatField("postgresql", metric))
-			metricsCounted++
-		}
+		assert.True(t, acc.HasFloatField("postgresql", metric))
+		metricsCounted++
 	}
 
 	for _, metric := range stringMetrics {
-		_, ok := availableColumns[metric]
-		if ok {
-			assert.True(t, acc.HasStringField("postgresql", metric))
-			metricsCounted++
-		}
+		assert.True(t, acc.HasStringField("postgresql", metric))
+		metricsCounted++
 	}
 
 	assert.True(t, metricsCounted > 0)
-	assert.Equal(t, len(availableColumns)-len(p.IgnoredColumns()), metricsCounted)
+	assert.Equal(t, len(floatMetrics)+len(intMetrics)+len(int32Metrics)+len(stringMetrics), metricsCounted)
 }
 
 func TestPostgresqlTagsMetricsWithDatabaseName(t *testing.T) {
@@ -112,15 +99,19 @@ func TestPostgresqlTagsMetricsWithDatabaseName(t *testing.T) {
 	}
 
 	p := &Postgresql{
-		Address: fmt.Sprintf("host=%s user=postgres sslmode=disable",
-			testutil.GetLocalHost()),
+		Service: Service{
+			Address: fmt.Sprintf(
+				"host=%s user=postgres sslmode=disable",
+				testutil.GetLocalHost(),
+			),
+		},
 		Databases: []string{"postgres"},
 	}
 
 	var acc testutil.Accumulator
 
-	err := p.Gather(&acc)
-	require.NoError(t, err)
+	require.NoError(t, p.Start(&acc))
+	require.NoError(t, p.Gather(&acc))
 
 	point, ok := acc.Get("postgresql")
 	require.True(t, ok)
@@ -134,14 +125,18 @@ func TestPostgresqlDefaultsToAllDatabases(t *testing.T) {
 	}
 
 	p := &Postgresql{
-		Address: fmt.Sprintf("host=%s user=postgres sslmode=disable",
-			testutil.GetLocalHost()),
+		Service: Service{
+			Address: fmt.Sprintf(
+				"host=%s user=postgres sslmode=disable",
+				testutil.GetLocalHost(),
+			),
+		},
 	}
 
 	var acc testutil.Accumulator
 
-	err := p.Gather(&acc)
-	require.NoError(t, err)
+	require.NoError(t, p.Start(&acc))
+	require.NoError(t, p.Gather(&acc))
 
 	var found bool
 
@@ -163,14 +158,17 @@ func TestPostgresqlIgnoresUnwantedColumns(t *testing.T) {
 	}
 
 	p := &Postgresql{
-		Address: fmt.Sprintf("host=%s user=postgres sslmode=disable",
-			testutil.GetLocalHost()),
+		Service: Service{
+			Address: fmt.Sprintf(
+				"host=%s user=postgres sslmode=disable",
+				testutil.GetLocalHost(),
+			),
+		},
 	}
 
 	var acc testutil.Accumulator
-
-	err := p.Gather(&acc)
-	require.NoError(t, err)
+	require.NoError(t, p.Start(&acc))
+	require.NoError(t, p.Gather(&acc))
 
 	for col := range p.IgnoredColumns() {
 		assert.False(t, acc.HasMeasurement(col))
@@ -183,15 +181,19 @@ func TestPostgresqlDatabaseWhitelistTest(t *testing.T) {
 	}
 
 	p := &Postgresql{
-		Address: fmt.Sprintf("host=%s user=postgres sslmode=disable",
-			testutil.GetLocalHost()),
+		Service: Service{
+			Address: fmt.Sprintf(
+				"host=%s user=postgres sslmode=disable",
+				testutil.GetLocalHost(),
+			),
+		},
 		Databases: []string{"template0"},
 	}
 
 	var acc testutil.Accumulator
 
-	err := p.Gather(&acc)
-	require.NoError(t, err)
+	require.NoError(t, p.Start(&acc))
+	require.NoError(t, p.Gather(&acc))
 
 	var foundTemplate0 = false
 	var foundTemplate1 = false
@@ -219,15 +221,18 @@ func TestPostgresqlDatabaseBlacklistTest(t *testing.T) {
 	}
 
 	p := &Postgresql{
-		Address: fmt.Sprintf("host=%s user=postgres sslmode=disable",
-			testutil.GetLocalHost()),
+		Service: Service{
+			Address: fmt.Sprintf(
+				"host=%s user=postgres sslmode=disable",
+				testutil.GetLocalHost(),
+			),
+		},
 		IgnoredDatabases: []string{"template0"},
 	}
 
 	var acc testutil.Accumulator
-
-	err := p.Gather(&acc)
-	require.NoError(t, err)
+	require.NoError(t, p.Start(&acc))
+	require.NoError(t, p.Gather(&acc))
 
 	var foundTemplate0 = false
 	var foundTemplate1 = false