Add stubbed out dev tsm engine

Starting to integrate some of the components into a engine that is
usable for development purposes.  This allows the code to evolve while
keeping the existing TSM engine in tact for reference.

Currently, just the WAL is wired up so writes can be tested.  Other engine
functions will panic the server if called.

tsdb/engine/tsm1/engine.go

@@ -0,0 +1,117 @@
+package tsm1
+
+import (
+	"io"
+	"log"
+	"os"
+	"sync"
+
+	"github.com/influxdb/influxdb/models"
+	"github.com/influxdb/influxdb/tsdb"
+)
+
+func init() {
+	tsdb.RegisterEngine("tsm1dev", NewDevEngine)
+}
+
+// Ensure Engine implements the interface.
+var _ tsdb.Engine = &DevEngine{}
+
+// Engine represents a storage engine with compressed blocks.
+type DevEngine struct {
+	mu sync.RWMutex
+
+	path   string
+	logger *log.Logger
+
+	WAL *WAL
+
+	RotateFileSize    uint32
+	MaxFileSize       uint32
+	MaxPointsPerBlock int
+}
+
+// NewDevEngine returns a new instance of Engine.
+func NewDevEngine(path string, walPath string, opt tsdb.EngineOptions) tsdb.Engine {
+	w := NewWAL(walPath)
+	w.LoggingEnabled = opt.Config.WALLoggingEnabled
+
+	e := &DevEngine{
+		path:   path,
+		logger: log.New(os.Stderr, "[tsm1] ", log.LstdFlags),
+
+		WAL:               w,
+		RotateFileSize:    DefaultRotateFileSize,
+		MaxFileSize:       MaxDataFileSize,
+		MaxPointsPerBlock: DefaultMaxPointsPerBlock,
+	}
+
+	return e
+}
+
+// Path returns the path the engine was opened with.
+func (e *DevEngine) Path() string { return e.path }
+
+// PerformMaintenance is for periodic maintenance of the store. A no-op for b1
+func (e *DevEngine) PerformMaintenance() {
+}
+
+// Format returns the format type of this engine
+func (e *DevEngine) Format() tsdb.EngineFormat {
+	return tsdb.TSM1Format
+}
+
+// Open opens and initializes the engine.
+func (e *DevEngine) Open() error {
+	if err := e.WAL.Open(); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// Close closes the engine.
+func (e *DevEngine) Close() error {
+	e.mu.Lock()
+	defer e.mu.Unlock()
+
+	e.WAL.Close()
+
+	return nil
+}
+
+// SetLogOutput is a no-op.
+func (e *DevEngine) SetLogOutput(w io.Writer) {}
+
+// LoadMetadataIndex loads the shard metadata into memory.
+func (e *DevEngine) LoadMetadataIndex(shard *tsdb.Shard, index *tsdb.DatabaseIndex, measurementFields map[string]*tsdb.MeasurementFields) error {
+	return nil
+}
+
+// WritePoints writes metadata and point data into the engine.
+// Returns an error if new points are added to an existing key.
+func (e *DevEngine) WritePoints(points []models.Point, measurementFieldsToSave map[string]*tsdb.MeasurementFields, seriesToCreate []*tsdb.SeriesCreate) error {
+	return e.WAL.WritePoints(points)
+}
+
+// DeleteSeries deletes the series from the engine.
+func (e *DevEngine) DeleteSeries(seriesKeys []string) error {
+	panic("not implemented")
+}
+
+// DeleteMeasurement deletes a measurement and all related series.
+func (e *DevEngine) DeleteMeasurement(name string, seriesKeys []string) error {
+	panic("not implemented")
+}
+
+// SeriesCount returns the number of series buckets on the shard.
+func (e *DevEngine) SeriesCount() (n int, err error) {
+	return 0, nil
+}
+
+// Begin starts a new transaction on the engine.
+func (e *DevEngine) Begin(writable bool) (tsdb.Tx, error) {
+	panic("not implemented")
+}
+
+func (e *DevEngine) WriteTo(w io.Writer) (n int64, err error) { panic("not implemented") }