mediocre-go-lib/mdb/mbigtable/bigtable.go

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// Package mbigtable implements connecting to Google's Bigtable service and
// simplifying a number of interactions with it.
package mbigtable
import (
"context"
"strings"
"cloud.google.com/go/bigtable"
"github.com/mediocregopher/mediocre-go-lib/mcfg"
"github.com/mediocregopher/mediocre-go-lib/mctx"
"github.com/mediocregopher/mediocre-go-lib/mdb"
"github.com/mediocregopher/mediocre-go-lib/merr"
"github.com/mediocregopher/mediocre-go-lib/mlog"
"github.com/mediocregopher/mediocre-go-lib/mrun"
)
func isErrAlreadyExists(err error) bool {
if err == nil {
return false
}
return strings.HasSuffix(err.Error(), " already exists")
}
// Bigtable is a wrapper around a bigtable client providing more functionality.
type Bigtable struct {
*bigtable.Client
Instance string
gce *mdb.GCE
ctx context.Context
}
// WithBigTable returns a Bigtable instance which will be initialized and
// configured when the start event is triggered on the returned Context (see
// mrun.Start). The Bigtable instance will have Close called on it when the
// stop event is triggered on the returned Context (see mrun.Stop).
//
// gce is optional and can be passed in if there's an existing gce object which
// should be used, otherwise a new one will be created with mdb.MGCE.
//
// defaultInstance can be given as the instance name to use as the default
// parameter value. If empty the parameter will be required to be set.
func WithBigTable(parent context.Context, gce *mdb.GCE, defaultInstance string) (context.Context, *Bigtable) {
ctx := mctx.NewChild(parent, "bigtable")
if gce == nil {
ctx, gce = mdb.WithGCE(ctx, "")
}
bt := &Bigtable{
gce: gce,
}
var inst *string
{
const name, descr = "instance", "name of the bigtable instance in the project to connect to"
if defaultInstance != "" {
ctx, inst = mcfg.WithString(ctx, name, defaultInstance, descr)
} else {
ctx, inst = mcfg.WithRequiredString(ctx, name, descr)
}
}
ctx = mrun.WithStartHook(ctx, func(innerCtx context.Context) error {
bt.Instance = *inst
bt.ctx = mctx.MergeAnnotations(bt.ctx, bt.gce.Context())
bt.ctx = mctx.Annotate(bt.ctx, "instance", bt.Instance)
mlog.Info("connecting to bigtable", bt.ctx)
var err error
bt.Client, err = bigtable.NewClient(
innerCtx,
bt.gce.Project, bt.Instance,
bt.gce.ClientOptions()...,
)
return merr.Wrap(bt.ctx, err)
})
ctx = mrun.WithStopHook(ctx, func(context.Context) error {
return bt.Client.Close()
})
bt.ctx = ctx
return mctx.WithChild(parent, ctx), bt
}
// EnsureTable ensures that the given table exists and has (at least) the given
// column families.
//
// This method requires admin privileges on the bigtable instance.
func (bt *Bigtable) EnsureTable(ctx context.Context, name string, colFams ...string) error {
ctx = mctx.MergeAnnotations(ctx, bt.ctx)
ctx = mctx.Annotate(ctx, "table", name)
mlog.Info("ensuring table", ctx)
mlog.Debug("creating admin client", ctx)
adminClient, err := bigtable.NewAdminClient(ctx, bt.gce.Project, bt.Instance)
if err != nil {
return merr.Wrap(ctx, err)
}
defer adminClient.Close()
mlog.Debug("creating bigtable table (if needed)", ctx)
err = adminClient.CreateTable(ctx, name)
if err != nil && !isErrAlreadyExists(err) {
return merr.Wrap(ctx, err)
}
for _, colFam := range colFams {
ctx := mctx.Annotate(ctx, "family", colFam)
mlog.Debug("creating bigtable column family (if needed)", ctx)
err := adminClient.CreateColumnFamily(ctx, name, colFam)
if err != nil && !isErrAlreadyExists(err) {
return merr.Wrap(ctx, err)
}
}
return nil
}
// Table returns the bigtable.Table instance which can be used to write/query
// the given table.
func (bt *Bigtable) Table(tableName string) *bigtable.Table {
return bt.Open(tableName)
}