[extension/storage/dbstorage] Create component (open-telemetry#7061)

* add dbstorage extension

* lint

* fix import

* make extensions test pass

* goimports

* add CODEOWNERS

* address code review

* code review - add missing link

.github/CODEOWNERS

@@ -65,6 +65,7 @@ extension/observer/                                  @open-telemetry/collector-c
 extension/observer/ecstaskobserver/                  @open-telemetry/collector-contrib-approvers @rmfitzpatrick
 extension/observer/k8sobserver/                      @open-telemetry/collector-contrib-approvers @rmfitzpatrick @dmitryax
 extension/oidcauthextension/                         @open-telemetry/collector-contrib-approvers @jpkrohling
+extension/storage/dbstorage/                         @open-telemetry/collector-contrib-approvers @dmitryax @atoulme
 extension/storage/filestorage/                       @open-telemetry/collector-contrib-approvers @djaglowski
 
 internal/aws/                                        @open-telemetry/collector-contrib-approvers @anuraaga @mxiamxia

CHANGELOG.md

@@ -52,6 +52,7 @@
 - `ecs_task_observer`: Discover running containers in AWS ECS tasks (#6894)
 - `mongodbreceiver`: Establish codebase for MongoDB metrics receiver (#6972)
 - `couchbasereceiver`: Establish codebase for Couchbase metrics receiver (#7046)
+- `dbstorage`: New experimental dbstorage extension (#7061)
 
 ## 🧰 Bug fixes 🧰
 

cmd/configschema/go.mod

@@ -150,6 +150,14 @@ require (
 	github.com/influxdata/influxdb-observability/influx2otel v0.2.10 // indirect
 	github.com/influxdata/influxdb-observability/otel2influx v0.2.10 // indirect
 	github.com/influxdata/line-protocol/v2 v2.2.1 // indirect
+	github.com/jackc/chunkreader/v2 v2.0.1 // indirect
+	github.com/jackc/pgconn v1.10.1 // indirect
+	github.com/jackc/pgio v1.0.0 // indirect
+	github.com/jackc/pgpassfile v1.0.0 // indirect
+	github.com/jackc/pgproto3/v2 v2.2.0 // indirect
+	github.com/jackc/pgservicefile v0.0.0-20200714003250-2b9c44734f2b // indirect
+	github.com/jackc/pgtype v1.9.1 // indirect
+	github.com/jackc/pgx/v4 v4.14.1 // indirect
 	github.com/jaegertracing/jaeger v1.29.0 // indirect
 	github.com/jcmturner/aescts/v2 v2.0.0 // indirect
 	github.com/jcmturner/dnsutils/v2 v2.0.0 // indirect
@@ -173,6 +181,7 @@ require (
 	github.com/mailru/easyjson v0.7.7 // indirect
 	github.com/mattn/go-colorable v0.1.12 // indirect
 	github.com/mattn/go-isatty v0.0.14 // indirect
+	github.com/mattn/go-sqlite3 v1.14.10 // indirect
 	github.com/matttproud/golang_protobuf_extensions v1.0.2-0.20181231171920-c182affec369 // indirect
 	github.com/microsoft/ApplicationInsights-Go v0.4.4 // indirect
 	github.com/miekg/dns v1.1.43 // indirect

extension/storage/dbstorage/README.md

@@ -0,0 +1,38 @@
+# Database Storage
+
+> :construction: This extension is in alpha. Configuration and functionality are subject to change.
+
+The Database Storage extension can persist state to a relational database. 
+
+The extension requires read and write access to a database table.
+
+`driver`: the name of the database driver to use. By default, the storage client supports "sqlite3" and "pgx".
+
+Implementors can add additional driver support by importing SQL drivers into the program.
+See [Golang database/sql package documentation](https://pkg.go.dev/database/sql) for more information.
+
+`datasource`: the url of the database, in the format accepted by the driver.
+
+
+```
+extensions:
+  db_storage:
+    driver: "sqlite3"
+    datasource: "foo.db?_busy_timeout=10000&_journal=WAL&_sync=NORMAL"
+
+service:
+  extensions: [db_storage]
+  pipelines:
+    traces:
+      receivers: [nop]
+      processors: [nop]
+      exporters: [nop]
+
+# Data pipeline is required to load the config.
+receivers:
+  nop:
+processors:
+  nop:
+exporters:
+  nop:
+```

extension/storage/dbstorage/client.go

@@ -0,0 +1,130 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package dbstorage // import "github.com/open-telemetry/opentelemetry-collector-contrib/extension/storage/dbstorage"
+
+import (
+	"context"
+	"database/sql"
+	"errors"
+	"fmt"
+
+	// Postgres driver
+	_ "github.com/jackc/pgx/v4/stdlib"
+	// SQLite driver
+	_ "github.com/mattn/go-sqlite3"
+	"go.opentelemetry.io/collector/extension/experimental/storage"
+)
+
+const (
+	createTable     = "create table if not exists %s (key text primary key, value blob)"
+	getQueryText    = "select value from %s where key=?"
+	setQueryText    = "insert into %s(key, value) values(?,?) on conflict(key) do update set value=?"
+	deleteQueryText = "delete from %s where key=?"
+)
+
+type dbStorageClient struct {
+	db          *sql.DB
+	getQuery    *sql.Stmt
+	setQuery    *sql.Stmt
+	deleteQuery *sql.Stmt
+}
+
+func newClient(ctx context.Context, db *sql.DB, tableName string) (*dbStorageClient, error) {
+	var err error
+	_, err = db.ExecContext(ctx, fmt.Sprintf(createTable, tableName))
+	if err != nil {
+		return nil, err
+	}
+
+	selectQuery, err := db.PrepareContext(ctx, fmt.Sprintf(getQueryText, tableName))
+	if err != nil {
+		return nil, err
+	}
+	setQuery, err := db.PrepareContext(ctx, fmt.Sprintf(setQueryText, tableName))
+	if err != nil {
+		return nil, err
+	}
+	deleteQuery, err := db.PrepareContext(ctx, fmt.Sprintf(deleteQueryText, tableName))
+	if err != nil {
+		return nil, err
+	}
+	return &dbStorageClient{db, selectQuery, setQuery, deleteQuery}, nil
+}
+
+// Get will retrieve data from storage that corresponds to the specified key
+func (c *dbStorageClient) Get(ctx context.Context, key string) ([]byte, error) {
+	rows, err := c.getQuery.QueryContext(ctx, key)
+	if err != nil {
+		return nil, err
+	}
+	if !rows.Next() {
+		return nil, nil
+	}
+	var result []byte
+	err = rows.Scan(&result)
+	if err != nil {
+		return result, err
+	}
+	err = rows.Close()
+	return result, err
+}
+
+// Set will store data. The data can be retrieved using the same key
+func (c *dbStorageClient) Set(ctx context.Context, key string, value []byte) error {
+	_, err := c.setQuery.ExecContext(ctx, key, value, value)
+	return err
+}
+
+// Delete will delete data associated with the specified key
+func (c *dbStorageClient) Delete(ctx context.Context, key string) error {
+	_, err := c.deleteQuery.ExecContext(ctx, key)
+	return err
+}
+
+// Batch executes the specified operations in order. Get operation results are updated in place
+func (c *dbStorageClient) Batch(ctx context.Context, ops ...storage.Operation) error {
+	var err error
+	for _, op := range ops {
+		switch op.Type {
+		case storage.Get:
+			op.Value, err = c.Get(ctx, op.Key)
+		case storage.Set:
+			err = c.Set(ctx, op.Key, op.Value)
+		case storage.Delete:
+			err = c.Delete(ctx, op.Key)
+		default:
+			return errors.New("wrong operation type")
+		}
+
+		if err != nil {
+			return err
+		}
+	}
+	return err
+}
+
+// Close will close the database
+func (c *dbStorageClient) Close(_ context.Context) error {
+	if err := c.setQuery.Close(); err != nil {
+		return err
+	}
+	if err := c.deleteQuery.Close(); err != nil {
+		return err
+	}
+	if err := c.getQuery.Close(); err != nil {
+		return err
+	}
+	return nil
+}

extension/storage/dbstorage/config.go

@@ -0,0 +1,39 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package dbstorage // import "github.com/open-telemetry/opentelemetry-collector-contrib/extension/storage/dbstorage"
+
+import (
+	"fmt"
+
+	"go.opentelemetry.io/collector/config"
+)
+
+// Config defines configuration for dbstorage extension.
+type Config struct {
+	config.ExtensionSettings `mapstructure:",squash"`
+	DriverName               string `mapstructure:"driver,omitempty"`
+	DataSource               string `mapstructure:"datasource,omitempty"`
+}
+
+func (cfg *Config) Validate() error {
+	if cfg.DataSource == "" {
+		return fmt.Errorf(fmt.Sprintf("missing datasource for %s", cfg.ID()))
+	}
+	if cfg.DriverName == "" {
+		return fmt.Errorf(fmt.Sprintf("missing driver name for %s", cfg.ID()))
+	}
+
+	return nil
+}

extension/storage/dbstorage/config_test.go

@@ -0,0 +1,55 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package dbstorage // import "github.com/open-telemetry/opentelemetry-collector-contrib/extension/storage/dbstorage"
+import (
+	"errors"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestConfig_Validate(t *testing.T) {
+	tests := []struct {
+		name      string
+		config    Config
+		errWanted error
+	}{
+		{
+			"Missing driver name",
+			Config{DataSource: "foo"},
+			errors.New("missing driver name for /blah"),
+		},
+		{
+			"Missing datasource",
+			Config{DriverName: "foo"},
+			errors.New("missing datasource for /blah"),
+		},
+		{
+			"valid",
+			Config{DriverName: "foo", DataSource: "bar"},
+			nil,
+		},
+	}
+
+	for _, test := range tests {
+		test.config.SetIDName("blah")
+		err := test.config.Validate()
+		if test.errWanted == nil {
+			assert.NoError(t, err)
+		} else {
+			assert.Equal(t, test.errWanted, err)
+		}
+	}
+}

extension/storage/dbstorage/extension.go

@@ -0,0 +1,91 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package dbstorage // import "github.com/open-telemetry/opentelemetry-collector-contrib/extension/storage/dbstorage"
+
+import (
+	"context"
+	"database/sql"
+	"fmt"
+	"strings"
+
+	"go.opentelemetry.io/collector/component"
+	"go.opentelemetry.io/collector/config"
+	"go.opentelemetry.io/collector/extension/experimental/storage"
+	"go.uber.org/zap"
+)
+
+type databaseStorage struct {
+	driverName     string
+	datasourceName string
+	logger         *zap.Logger
+	db             *sql.DB
+}
+
+// Ensure this storage extension implements the appropriate interface
+var _ storage.Extension = (*databaseStorage)(nil)
+
+func newDBStorage(logger *zap.Logger, config *Config) (component.Extension, error) {
+	return &databaseStorage{
+		driverName:     config.DriverName,
+		datasourceName: config.DataSource,
+		logger:         logger,
+	}, nil
+}
+
+// Start opens a connection to the database
+func (ds *databaseStorage) Start(context.Context, component.Host) error {
+	db, err := sql.Open(ds.driverName, ds.datasourceName)
+	if err != nil {
+		return err
+	}
+
+	if err := db.Ping(); err != nil {
+		return err
+	}
+	ds.db = db
+	return nil
+}
+
+// Shutdown closes the connection to the database
+func (ds *databaseStorage) Shutdown(context.Context) error {
+	return ds.db.Close()
+}
+
+// GetClient returns a storage client for an individual component
+func (ds *databaseStorage) GetClient(ctx context.Context, kind component.Kind, ent config.ComponentID, name string) (storage.Client, error) {
+	var fullName string
+	if name == "" {
+		fullName = fmt.Sprintf("%s_%s_%s", kindString(kind), ent.Type(), ent.Name())
+	} else {
+		fullName = fmt.Sprintf("%s_%s_%s_%s", kindString(kind), ent.Type(), ent.Name(), name)
+	}
+	fullName = strings.ReplaceAll(fullName, " ", "")
+	return newClient(ctx, ds.db, fullName)
+}
+
+func kindString(k component.Kind) string {
+	switch k {
+	case component.KindReceiver:
+		return "receiver"
+	case component.KindProcessor:
+		return "processor"
+	case component.KindExporter:
+		return "exporter"
+	case component.KindExtension:
+		return "extension"
+	default:
+		return "other" // not expected
+	}
+}