storage/cockroachkv: initial client implementation

Change-Id: I72ae558739b2ca532f31cb64f480b43437b6b309
This commit is contained in:
Jeff Wendling 2019-12-03 10:40:04 -07:00
parent 8e9532dbd9
commit f15192ea40
4 changed files with 493 additions and 0 deletions

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// Copyright (C) 2019 Storj Labs, Inc.
// See LICENSE for copying information.
package cockroachkv
import (
"bytes"
"context"
"database/sql"
"net/url"
"path"
"github.com/cockroachdb/cockroach-go/crdb"
"github.com/lib/pq"
"github.com/zeebo/errs"
monkit "gopkg.in/spacemonkeygo/monkit.v2"
"storj.io/storj/private/dbutil"
"storj.io/storj/storage"
)
const defaultBatchSize = 128
var (
mon = monkit.Package()
)
// Client is the entrypoint into a cockroachkv data store
type Client struct {
URL string
conn *sql.DB
}
func modifyURL(dbURL string) (modifiedURL string, databaseName string, err error) {
u, err := url.Parse(dbURL)
if err != nil {
return "", "", err
}
u.Scheme = "postgres"
q := u.Query()
if schema := q.Get("search_path"); schema != "" {
u.Path = path.Join(u.Path, schema)
q.Del("search_path")
u.RawQuery = q.Encode()
}
return u.String(), u.Path[1:], nil
}
// New instantiates a new postgreskv client given db URL
func New(dbURL string) (*Client, error) {
modifiedURL, _, err := modifyURL(dbURL)
if err != nil {
return nil, err
}
conn, err := sql.Open("postgres", modifiedURL)
if err != nil {
return nil, err
}
dbutil.Configure(conn, mon)
// TODO: Need to bring this back but sourcing CockroachDB compatible schema.
// err = schema.PrepareDB(pgConn, dbURL)
// if err != nil {
// return nil, err
// }
return &Client{
URL: modifiedURL,
conn: conn,
}, nil
}
// Close closes the client
func (client *Client) Close() error {
return client.conn.Close()
}
// TODO: Need to bring this back but sourcing CockroachDB compatible schema.
// DropSchema drops the schema.
// func (client *Client) DropSchema(schema string) error {
// return pgutil.DropSchema(client.pgConn, schema)
// }
// Put sets the value for the provided key.
func (client *Client) Put(ctx context.Context, key storage.Key, value storage.Value) (err error) {
defer mon.Task()(&ctx)(&err)
if key.IsZero() {
return storage.ErrEmptyKey.New("")
}
q := `
INSERT INTO pathdata (fullpath, metadata)
VALUES ($1:::BYTEA, $2:::BYTEA)
ON CONFLICT (fullpath) DO UPDATE SET metadata = EXCLUDED.metadata
`
_, err = client.conn.Exec(q, []byte(key), []byte(value))
return Error.Wrap(err)
}
// Get looks up the provided key and returns its value (or an error).
func (client *Client) Get(ctx context.Context, key storage.Key) (_ storage.Value, err error) {
defer mon.Task()(&ctx)(&err)
if key.IsZero() {
return nil, storage.ErrEmptyKey.New("")
}
q := "SELECT metadata FROM pathdata WHERE fullpath = $1:::BYTEA"
row := client.conn.QueryRow(q, []byte(key))
var val []byte
err = row.Scan(&val)
if err == sql.ErrNoRows {
return nil, storage.ErrKeyNotFound.New("%q", key)
}
return val, Error.Wrap(err)
}
// GetAll finds all values for the provided keys (up to storage.LookupLimit).
// If more keys are provided than the maximum, an error will be returned.
func (client *Client) GetAll(ctx context.Context, keys storage.Keys) (_ storage.Values, err error) {
defer mon.Task()(&ctx)(&err)
if len(keys) > storage.LookupLimit {
return nil, storage.ErrLimitExceeded
}
q := `
SELECT metadata
FROM pathdata pd
RIGHT JOIN
unnest($1:::BYTEA[]) WITH ORDINALITY pk(request, ord)
ON (pd.fullpath = pk.request)
ORDER BY pk.ord
`
rows, err := client.conn.Query(q, pq.ByteaArray(keys.ByteSlices()))
if err != nil {
return nil, errs.Wrap(err)
}
defer func() { err = errs.Combine(err, Error.Wrap(rows.Close())) }()
values := make([]storage.Value, 0, len(keys))
for rows.Next() {
var value []byte
if err := rows.Scan(&value); err != nil {
return nil, Error.Wrap(err)
}
values = append(values, storage.Value(value))
}
return values, Error.Wrap(rows.Err())
}
// Delete deletes the given key and its associated value.
func (client *Client) Delete(ctx context.Context, key storage.Key) (err error) {
defer mon.Task()(&ctx)(&err)
if key.IsZero() {
return storage.ErrEmptyKey.New("")
}
q := "DELETE FROM pathdata WHERE fullpath = $1:::BYTEA"
result, err := client.conn.Exec(q, []byte(key))
if err != nil {
return err
}
numRows, err := result.RowsAffected()
if err != nil {
return err
}
if numRows == 0 {
return storage.ErrKeyNotFound.New("%q", key)
}
return nil
}
// List returns either a list of known keys, in order, or an error.
func (client *Client) List(ctx context.Context, first storage.Key, limit int) (_ storage.Keys, err error) {
defer mon.Task()(&ctx)(&err)
return storage.ListKeys(ctx, client, first, limit)
}
// Iterate calls the callback with an iterator over the keys.
func (client *Client) Iterate(ctx context.Context, opts storage.IterateOptions, fn func(context.Context, storage.Iterator) error) (err error) {
defer mon.Task()(&ctx)(&err)
opi, err := newOrderedCockroachIterator(ctx, client, opts, defaultBatchSize)
if err != nil {
return err
}
defer func() {
err = errs.Combine(err, opi.Close())
}()
return fn(ctx, opi)
}
// CompareAndSwap atomically compares and swaps oldValue with newValue
func (client *Client) CompareAndSwap(ctx context.Context, key storage.Key, oldValue, newValue storage.Value) (err error) {
defer mon.Task()(&ctx)(&err)
if key.IsZero() {
return storage.ErrEmptyKey.New("")
}
if oldValue == nil && newValue == nil {
q := "SELECT metadata FROM pathdata WHERE fullpath = $1:::BYTEA"
row := client.conn.QueryRow(q, []byte(key))
var val []byte
err = row.Scan(&val)
if err == sql.ErrNoRows {
return nil
}
if err != nil {
return Error.Wrap(err)
}
return storage.ErrValueChanged.New("%q", key)
}
if oldValue == nil {
q := `
INSERT INTO pathdata (fullpath, metadata) VALUES ($1:::BYTEA, $2:::BYTEA)
ON CONFLICT DO NOTHING
RETURNING 1
`
row := client.conn.QueryRow(q, []byte(key), []byte(newValue))
var val []byte
err = row.Scan(&val)
if err == sql.ErrNoRows {
return storage.ErrValueChanged.New("%q", key)
}
return Error.Wrap(err)
}
return crdb.ExecuteTx(ctx, client.conn, nil, func(txn *sql.Tx) error {
q := "SELECT metadata FROM pathdata WHERE fullpath = $1:::BYTEA;"
row := txn.QueryRowContext(ctx, q, []byte(key))
var metadata []byte
err = row.Scan(&metadata)
if err == sql.ErrNoRows {
// Row not found for this fullpath.
// Potentially because another concurrent transaction changed the row.
return storage.ErrKeyNotFound.New("%q", key)
}
if err != nil {
return Error.Wrap(err)
}
if equal := bytes.Compare(metadata, oldValue); equal != 0 {
// If the row is found but the metadata has been already changed
// we can't continue to delete it.
return storage.ErrValueChanged.New("%q", key)
}
var res sql.Result
if newValue == nil {
q = `
DELETE FROM pathdata
WHERE pathdata.fullpath = $1:::BYTEA
AND pathdata.metadata = $2:::BYTEA
`
res, err = txn.ExecContext(ctx, q, []byte(key), []byte(oldValue))
} else {
q = `
UPDATE pathdata
SET metadata = $3:::BYTEA
WHERE pathdata.fullpath = $1:::BYTEA
AND pathdata.metadata = $2:::BYTEA
`
res, err = txn.ExecContext(ctx, q, []byte(key), []byte(oldValue), []byte(newValue))
}
if err != nil {
return Error.Wrap(err)
}
affected, err := res.RowsAffected()
if err != nil {
return Error.Wrap(err)
}
if affected != 1 {
return storage.ErrValueChanged.New("%q", key)
}
return nil
})
}

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// Copyright (C) 2019 Storj Labs, Inc.
// See LICENSE for copying information.
package cockroachkv
import (
"testing"
_ "github.com/lib/pq"
"storj.io/storj/private/dbutil/pgutil/pgtest"
"storj.io/storj/storage/testsuite"
)
func newTestCockroachDB(t testing.TB) (store *Client, cleanup func()) {
if *pgtest.CrdbConnStr == "" {
t.Skipf("postgres flag missing, example:\n-cockroach-test-db=%s", pgtest.DefaultCrdbConnStr)
}
crdb, err := New(*pgtest.CrdbConnStr)
if err != nil {
t.Fatalf("init: %+v", err)
}
return crdb, func() {
if err := crdb.Close(); err != nil {
t.Fatalf("failed to close db: %v", err)
}
}
}
func TestSuite(t *testing.T) {
store, cleanup := newTestCockroachDB(t)
defer cleanup()
testsuite.RunTests(t, store)
}

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// Copyright (C) 2019 Storj Labs, Inc.
// See LICENSE for copying information.
package cockroachkv
import (
"github.com/zeebo/errs"
)
// Error is the default postgreskv errs class
var Error = errs.Class("cockroachkv error")

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// Copyright (C) 2019 Storj Labs, Inc.
// See LICENSE for copying information.
package cockroachkv
import (
"bytes"
"context"
"database/sql"
"fmt"
"github.com/zeebo/errs"
"storj.io/storj/storage"
)
type orderedCockroachIterator struct {
client *Client
opts *storage.IterateOptions
delimiter byte
batchSize int
curIndex int
curRows *sql.Rows
skipPrefix bool
lastKeySeen storage.Key
largestKey storage.Key
errEncountered error
}
func newOrderedCockroachIterator(ctx context.Context, cli *Client, opts storage.IterateOptions, batchSize int) (_ *orderedCockroachIterator, err error) {
defer mon.Task()(&ctx)(&err)
if opts.Prefix == nil {
opts.Prefix = storage.Key("")
}
if opts.First == nil {
opts.First = storage.Key("")
}
if opts.First.Less(opts.Prefix) {
opts.First = opts.Prefix
}
opi := &orderedCockroachIterator{
client: cli,
opts: &opts,
delimiter: byte('/'),
batchSize: batchSize,
curIndex: 0,
}
if len(opts.Prefix) > 0 {
opi.largestKey = storage.AfterPrefix(opts.Prefix)
}
newRows, err := opi.doNextQuery(ctx)
if err != nil {
return nil, err
}
opi.curRows = newRows
return opi, nil
}
func (opi *orderedCockroachIterator) Close() error {
return errs.Combine(opi.errEncountered, opi.curRows.Close())
}
// Next fills in info for the next item in an ongoing listing.
func (opi *orderedCockroachIterator) Next(ctx context.Context, item *storage.ListItem) bool {
defer mon.Task()(&ctx)(nil)
for {
for !opi.curRows.Next() {
if err := opi.curRows.Err(); err != nil && err != sql.ErrNoRows {
opi.errEncountered = errs.Wrap(err)
return false
}
if err := opi.curRows.Close(); err != nil {
opi.errEncountered = errs.Wrap(err)
return false
}
if opi.curIndex < opi.batchSize {
return false
}
newRows, err := opi.doNextQuery(ctx)
if err != nil {
opi.errEncountered = errs.Wrap(err)
return false
}
opi.curRows = newRows
opi.curIndex = 0
}
var k, v []byte
err := opi.curRows.Scan(&k, &v)
if err != nil {
opi.errEncountered = errs.Wrap(err)
return false
}
opi.curIndex++
if !bytes.HasPrefix(k, []byte(opi.opts.Prefix)) {
return false
}
item.Key = storage.Key(k)
item.Value = storage.Value(v)
item.IsPrefix = false
if !opi.opts.Recurse {
if idx := bytes.IndexByte(item.Key[len(opi.opts.Prefix):], opi.delimiter); idx >= 0 {
item.Key = item.Key[:len(opi.opts.Prefix)+idx+1]
item.Value = nil
item.IsPrefix = true
}
}
if opi.lastKeySeen.Equal(item.Key) {
continue
}
opi.skipPrefix = item.IsPrefix
opi.lastKeySeen = item.Key
return true
}
}
func (opi *orderedCockroachIterator) doNextQuery(ctx context.Context) (_ *sql.Rows, err error) {
defer mon.Task()(&ctx)(&err)
gt := ">"
start := opi.lastKeySeen
if len(start) == 0 {
start = opi.opts.First
gt = ">="
} else if opi.skipPrefix {
start = storage.AfterPrefix(start)
gt = ">="
}
return opi.client.conn.Query(fmt.Sprintf(`
SELECT pd.fullpath, pd.metadata
FROM pathdata pd
WHERE pd.fullpath %s $1:::BYTEA
AND ($2:::BYTEA = '':::BYTEA OR pd.fullpath < $2:::BYTEA)
LIMIT $3
`, gt), start, []byte(opi.largestKey), opi.batchSize)
}