feat(outputs.cratedb): Allow configuration of startup error handling (#15065)

plugins/outputs/cratedb/README.md

@@ -36,15 +36,20 @@ See the [CONFIGURATION.md][CONFIGURATION.md] for more details.
 ```toml @sample.conf
 # Configuration for CrateDB to send metrics to.
 [[outputs.cratedb]]
-  # A github.com/jackc/pgx/v4 connection string.
-  # See https://pkg.go.dev/github.com/jackc/pgx/v4#ParseConfig
+  ## Connection parameters for accessing the database see
+  ##   https://pkg.go.dev/github.com/jackc/pgx/v4#ParseConfig
+  ## for available options
   url = "postgres://user:password@localhost/schema?sslmode=disable"
-  # Timeout for all CrateDB queries.
-  timeout = "5s"
-  # Name of the table to store metrics in.
-  table = "metrics"
-  # If true, and the metrics table does not exist, create it automatically.
-  table_create = true
-  # The character(s) to replace any '.' in an object key with
-  key_separator = "_"
+
+  ## Timeout for all CrateDB queries.
+  # timeout = "5s"
+
+  ## Name of the table to store metrics in.
+  # table = "metrics"
+
+  ## If true, and the metrics table does not exist, create it automatically.
+  # table_create = false
+
+  ## The character(s) to replace any '.' in an object key with
+  # key_separator = "_"
 ```

plugins/outputs/cratedb/cratedb.go

@@ -17,6 +17,7 @@ import (
 
 	"github.com/influxdata/telegraf"
 	"github.com/influxdata/telegraf/config"
+	"github.com/influxdata/telegraf/internal"
 	"github.com/influxdata/telegraf/plugins/outputs"
 )
 
@@ -25,26 +26,8 @@ var sampleConfig string
 
 const MaxInt64 = int64(^uint64(0) >> 1)
 
-type CrateDB struct {
-	URL          string
-	Timeout      config.Duration
-	Table        string
-	TableCreate  bool   `toml:"table_create"`
-	KeySeparator string `toml:"key_separator"`
-	DB           *sql.DB
-}
-
-func (*CrateDB) SampleConfig() string {
-	return sampleConfig
-}
-
-func (c *CrateDB) Connect() error {
-	db, err := sql.Open("pgx", c.URL)
-	if err != nil {
-		return err
-	} else if c.TableCreate {
-		query := `
-CREATE TABLE IF NOT EXISTS ` + c.Table + ` (
+const tableCreationQuery = `
+CREATE TABLE IF NOT EXISTS %s (
 	"hash_id" LONG INDEX OFF,
 	"timestamp" TIMESTAMP,
 	"name" STRING,
@@ -54,13 +37,52 @@ CREATE TABLE IF NOT EXISTS ` + c.Table + ` (
 	PRIMARY KEY ("timestamp", "hash_id","day")
 ) PARTITIONED BY("day");
 `
-		ctx, cancel := context.WithTimeout(context.Background(), time.Duration(c.Timeout))
-		defer cancel()
-		if _, err := db.ExecContext(ctx, query); err != nil {
+
+type CrateDB struct {
+	URL          string          `toml:"url"`
+	Timeout      config.Duration `toml:"timeout"`
+	Table        string          `toml:"table"`
+	TableCreate  bool            `toml:"table_create"`
+	KeySeparator string          `toml:"key_separator"`
+
+	db *sql.DB
+}
+
+func (*CrateDB) SampleConfig() string {
+	return sampleConfig
+}
+
+func (c *CrateDB) Init() error {
+	// Set defaults
+	if c.KeySeparator == "" {
+		c.KeySeparator = "_"
+	}
+	if c.Table == "" {
+		c.Table = "metrics"
+	}
+
+	return nil
+}
+
+func (c *CrateDB) Connect() error {
+	if c.db == nil {
+		db, err := sql.Open("pgx", c.URL)
+		if err != nil {
 			return err
 		}
+		c.db = db
 	}
-	c.DB = db
+
+	if c.TableCreate {
+		ctx, cancel := context.WithTimeout(context.Background(), time.Duration(c.Timeout))
+		defer cancel()
+
+		query := fmt.Sprintf(tableCreationQuery, c.Table)
+		if _, err := c.db.ExecContext(ctx, query); err != nil {
+			return &internal.StartupError{Err: err, Retry: true}
+		}
+	}
+
 	return nil
 }
 
@@ -73,7 +95,7 @@ func (c *CrateDB) Write(metrics []telegraf.Metric) error {
 		return err
 	}
 
-	_, err = c.DB.ExecContext(ctx, generatedSQL)
+	_, err = c.db.ExecContext(ctx, generatedSQL)
 	if err != nil {
 		return err
 	}
@@ -225,7 +247,10 @@ func hashID(m telegraf.Metric) int64 {
 }
 
 func (c *CrateDB) Close() error {
-	return c.DB.Close()
+	if c.db == nil {
+		return nil
+	}
+	return c.db.Close()
 }
 
 func init() {

plugins/outputs/cratedb/cratedb_test.go

@@ -12,7 +12,9 @@ import (
 
 	"github.com/influxdata/telegraf"
 	"github.com/influxdata/telegraf/config"
+	"github.com/influxdata/telegraf/internal"
 	"github.com/influxdata/telegraf/metric"
+	"github.com/influxdata/telegraf/models"
 	"github.com/influxdata/telegraf/testutil"
 )
 
@@ -46,7 +48,6 @@ func TestConnectAndWriteIntegration(t *testing.T) {
 	defer container.Terminate()
 	url := fmt.Sprintf("postgres://crate@%s:%s/test", container.Address, container.Ports[servicePort])
 
-	fmt.Println(url)
 	db, err := sql.Open("pgx", url)
 	require.NoError(t, err)
 	defer db.Close()
@@ -77,6 +78,76 @@ func TestConnectAndWriteIntegration(t *testing.T) {
 	require.NoError(t, c.Close())
 }
 
+func TestConnectionIssueAtStartup(t *testing.T) {
+	// Test case for https://github.com/influxdata/telegraf/issues/13278
+	if testing.Short() {
+		t.Skip("Skipping integration test in short mode")
+	}
+
+	container := testutil.Container{
+		Image:        "crate",
+		ExposedPorts: []string{servicePort},
+		Entrypoint: []string{
+			"/docker-entrypoint.sh",
+			"-Cdiscovery.type=single-node",
+		},
+		WaitingFor: wait.ForAll(
+			wait.ForListeningPort(servicePort),
+			wait.ForLog("recovered [0] indices into cluster_state"),
+		),
+	}
+	require.NoError(t, container.Start(), "failed to start container")
+	defer container.Terminate()
+	url := fmt.Sprintf("postgres://crate@%s:%s/test", container.Address, container.Ports[servicePort])
+
+	// Pause the container for connectivity issues
+	require.NoError(t, container.Pause())
+
+	// Create a model to be able to use the startup retry strategy
+	plugin := &CrateDB{
+		URL:         url,
+		Table:       "testing",
+		Timeout:     config.Duration(time.Second * 5),
+		TableCreate: true,
+	}
+	model := models.NewRunningOutput(
+		plugin,
+		&models.OutputConfig{
+			Name:                 "cratedb",
+			StartupErrorBehavior: "retry",
+		},
+		1000, 1000,
+	)
+	require.NoError(t, model.Init())
+
+	// The connect call should succeed even though the table creation was not
+	// successful due to the "retry" strategy
+	require.NoError(t, model.Connect())
+
+	// Writing the metrics in this state should fail because we are not fully
+	// started up
+	metrics := testutil.MockMetrics()
+	for _, m := range metrics {
+		model.AddMetric(m)
+	}
+	require.ErrorIs(t, model.WriteBatch(), internal.ErrNotConnected)
+
+	// Unpause the container, now writes should succeed
+	require.NoError(t, container.Resume())
+	require.NoError(t, model.WriteBatch())
+	defer model.Close()
+
+	// Verify that the metrics were actually written
+	for _, m := range metrics {
+		mid := hashID(m)
+		row := plugin.db.QueryRow("SELECT hash_id FROM testing WHERE hash_id = ? AND timestamp = ?", mid, m.Time())
+
+		var id int64
+		require.NoError(t, row.Scan(&id))
+		require.Equal(t, id, mid)
+	}
+}
+
 func TestInsertSQL(t *testing.T) {
 	tests := []struct {
 		Metrics []telegraf.Metric

plugins/outputs/cratedb/sample.conf

@@ -1,13 +1,18 @@
 # Configuration for CrateDB to send metrics to.
 [[outputs.cratedb]]
-  # A github.com/jackc/pgx/v4 connection string.
-  # See https://pkg.go.dev/github.com/jackc/pgx/v4#ParseConfig
+  ## Connection parameters for accessing the database see
+  ##   https://pkg.go.dev/github.com/jackc/pgx/v4#ParseConfig
+  ## for available options
   url = "postgres://user:password@localhost/schema?sslmode=disable"
-  # Timeout for all CrateDB queries.
-  timeout = "5s"
-  # Name of the table to store metrics in.
-  table = "metrics"
-  # If true, and the metrics table does not exist, create it automatically.
-  table_create = true
-  # The character(s) to replace any '.' in an object key with
-  key_separator = "_"
+
+  ## Timeout for all CrateDB queries.
+  # timeout = "5s"
+
+  ## Name of the table to store metrics in.
+  # table = "metrics"
+
+  ## If true, and the metrics table does not exist, create it automatically.
+  # table_create = false
+
+  ## The character(s) to replace any '.' in an object key with
+  # key_separator = "_"

testutil/container.go

@@ -156,3 +156,21 @@ func (c *Container) Terminate() {
 
 	c.PrintLogs()
 }
+
+func (c *Container) Pause() error {
+	provider, err := testcontainers.NewDockerProvider()
+	if err != nil {
+		return fmt.Errorf("getting provider failed: %w", err)
+	}
+
+	return provider.Client().ContainerPause(c.ctx, c.container.GetContainerID())
+}
+
+func (c *Container) Resume() error {
+	provider, err := testcontainers.NewDockerProvider()
+	if err != nil {
+		return fmt.Errorf("getting provider failed: %w", err)
+	}
+
+	return provider.Client().ContainerUnpause(c.ctx, c.container.GetContainerID())
+}