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client.go
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client.go
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// Copyright (C) 2019 Storj Labs, Inc.
// See LICENSE for copying information.
package postgreskv
import (
"context"
"database/sql"
"fmt"
"github.com/lib/pq"
"github.com/zeebo/errs"
monkit "gopkg.in/spacemonkeygo/monkit.v2"
"storj.io/storj/internal/dbutil"
"storj.io/storj/internal/dbutil/pgutil"
"storj.io/storj/storage"
"storj.io/storj/storage/postgreskv/schema"
)
const (
defaultBatchSize = 10000
defaultBucket = ""
)
var (
mon = monkit.Package()
)
// Client is the entrypoint into a postgreskv data store
type Client struct {
URL string
pgConn *sql.DB
}
// New instantiates a new postgreskv client given db URL
func New(dbURL string) (*Client, error) {
pgConn, err := sql.Open("postgres", dbURL)
if err != nil {
return nil, err
}
dbutil.Configure(pgConn, mon)
err = schema.PrepareDB(pgConn, dbURL)
if err != nil {
return nil, err
}
return &Client{
URL: dbURL,
pgConn: pgConn,
}, nil
}
// 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)
return client.PutPath(ctx, storage.Key(defaultBucket), key, value)
}
// PutPath sets the value for the provided key (in the given bucket).
func (client *Client) PutPath(ctx context.Context, bucket, key storage.Key, value storage.Value) (err error) {
defer mon.Task()(&ctx)(&err)
if key.IsZero() {
return storage.ErrEmptyKey.New("")
}
q := `
INSERT INTO pathdata (bucket, fullpath, metadata)
VALUES ($1::BYTEA, $2::BYTEA, $3::BYTEA)
ON CONFLICT (bucket, fullpath) DO UPDATE SET metadata = EXCLUDED.metadata
`
_, err = client.pgConn.Exec(q, []byte(bucket), []byte(key), []byte(value))
return 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)
return client.GetPath(ctx, storage.Key(defaultBucket), key)
}
// GetPath looks up the provided key (in the given bucket) and returns its value (or an error).
func (client *Client) GetPath(ctx context.Context, bucket, 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 bucket = $1::BYTEA AND fullpath = $2::BYTEA"
row := client.pgConn.QueryRow(q, []byte(bucket), []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)
}
// 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)
return client.DeletePath(ctx, storage.Key(defaultBucket), key)
}
// DeletePath deletes the given key (in the given bucket) and its associated value.
func (client *Client) DeletePath(ctx context.Context, bucket, key storage.Key) (err error) {
defer mon.Task()(&ctx)(&err)
if key.IsZero() {
return storage.ErrEmptyKey.New("")
}
q := "DELETE FROM pathdata WHERE bucket = $1::BYTEA AND fullpath = $2::BYTEA"
result, err := client.pgConn.Exec(q, []byte(bucket), []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)
}
// Close closes the client
func (client *Client) Close() error {
return client.pgConn.Close()
}
// 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)
return client.GetAllPath(ctx, storage.Key(defaultBucket), keys)
}
// GetAllPath finds all values for the provided keys (up to storage.LookupLimit)
// in the given bucket. if more keys are provided than the maximum, an error
// will be returned.
func (client *Client) GetAllPath(ctx context.Context, bucket storage.Key, 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($2::BYTEA[]) WITH ORDINALITY pk(request, ord)
ON (pd.fullpath = pk.request AND pd.bucket = $1::BYTEA)
ORDER BY pk.ord
`
rows, err := client.pgConn.Query(q, []byte(bucket), pq.ByteaArray(keys.ByteSlices()))
if err != nil {
return nil, errs.Wrap(err)
}
values := make([]storage.Value, 0, len(keys))
for rows.Next() {
var value []byte
if err := rows.Scan(&value); err != nil {
return nil, errs.Wrap(errs.Combine(err, rows.Close()))
}
values = append(values, storage.Value(value))
}
return values, errs.Combine(rows.Err(), rows.Close())
}
type orderedPostgresIterator struct {
client *Client
opts *storage.IterateOptions
bucket storage.Key
delimiter byte
batchSize int
curIndex int
curRows *sql.Rows
lastKeySeen storage.Key
errEncountered error
nextQuery func(context.Context) (*sql.Rows, error)
}
// Next fills in info for the next item in an ongoing listing.
func (opi *orderedPostgresIterator) Next(ctx context.Context, item *storage.ListItem) bool {
defer mon.Task()(&ctx)(nil)
if !opi.curRows.Next() {
if err := opi.curRows.Close(); err != nil {
opi.errEncountered = errs.Wrap(err)
return false
}
if opi.curIndex < opi.batchSize {
return false
}
if err := opi.curRows.Err(); err != nil {
opi.errEncountered = errs.Wrap(err)
return false
}
newRows, err := opi.nextQuery(ctx)
if err != nil {
opi.errEncountered = errs.Wrap(err)
return false
}
opi.curRows = newRows
opi.curIndex = 0
if !opi.curRows.Next() {
if err := opi.curRows.Close(); err != nil {
opi.errEncountered = errs.Wrap(err)
}
return false
}
}
var k, v []byte
err := opi.curRows.Scan(&k, &v)
if err != nil {
opi.errEncountered = errs.Combine(errs.Wrap(err), errs.Wrap(opi.curRows.Close()))
return false
}
item.Key = storage.Key(k)
item.Value = storage.Value(v)
opi.curIndex++
if opi.curIndex == 1 && opi.lastKeySeen.Equal(item.Key) {
return opi.Next(ctx, item)
}
if !opi.opts.Recurse && item.Key[len(item.Key)-1] == opi.delimiter && !item.Key.Equal(opi.opts.Prefix) {
item.IsPrefix = true
// i don't think this makes the most sense, but it's necessary to pass the storage testsuite
item.Value = nil
} else {
item.IsPrefix = false
}
opi.lastKeySeen = item.Key
return true
}
func (opi *orderedPostgresIterator) doNextQuery(ctx context.Context) (_ *sql.Rows, err error) {
defer mon.Task()(&ctx)(&err)
start := opi.lastKeySeen
if start == nil {
start = opi.opts.First
}
var query string
if !opi.opts.Recurse {
if opi.opts.Reverse {
query = "SELECT p, m FROM list_directory_reverse($1::BYTEA, $2::BYTEA, $3::BYTEA, $4) ld(p, m)"
} else {
query = "SELECT p, m FROM list_directory($1::BYTEA, $2::BYTEA, $3::BYTEA, $4) ld(p, m)"
}
} else {
startCmp := ">="
orderDir := ""
if opi.opts.Reverse {
startCmp = "<="
orderDir = " DESC"
}
query = fmt.Sprintf(`
SELECT fullpath, metadata
FROM pathdata
WHERE bucket = $1::BYTEA
AND ($2::BYTEA = ''::BYTEA OR fullpath >= $2::BYTEA)
AND ($2::BYTEA = ''::BYTEA OR fullpath < bytea_increment($2::BYTEA))
AND ($3::BYTEA = ''::BYTEA OR fullpath %s $3::BYTEA)
ORDER BY fullpath%s
LIMIT $4
`, startCmp, orderDir)
}
return opi.client.pgConn.Query(query, []byte(opi.bucket), []byte(opi.opts.Prefix), []byte(start), opi.batchSize+1)
}
func (opi *orderedPostgresIterator) Close() error {
return errs.Combine(opi.errEncountered, opi.curRows.Close())
}
func newOrderedPostgresIterator(ctx context.Context, pgClient *Client, opts storage.IterateOptions, batchSize int) (_ *orderedPostgresIterator, err error) {
defer mon.Task()(&ctx)(&err)
if opts.Prefix == nil {
opts.Prefix = storage.Key("")
}
if opts.First == nil {
opts.First = storage.Key("")
}
opi := &orderedPostgresIterator{
client: pgClient,
opts: &opts,
bucket: storage.Key(defaultBucket),
delimiter: byte('/'),
batchSize: batchSize,
curIndex: 0,
}
opi.nextQuery = opi.doNextQuery
newRows, err := opi.nextQuery(ctx)
if err != nil {
return nil, err
}
opi.curRows = newRows
return opi, nil
}
// Iterate iterates over items based on opts
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 := newOrderedPostgresIterator(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)
return client.CompareAndSwapPath(ctx, storage.Key(defaultBucket), key, oldValue, newValue)
}
// CompareAndSwapPath atomically compares and swaps oldValue with newValue in the given bucket
func (client *Client) CompareAndSwapPath(ctx context.Context, bucket, 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 bucket = $1::BYTEA AND fullpath = $2::BYTEA"
row := client.pgConn.QueryRow(q, []byte(bucket), []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 (bucket, fullpath, metadata) VALUES ($1::BYTEA, $2::BYTEA, $3::BYTEA)
ON CONFLICT DO NOTHING
RETURNING 1
`
row := client.pgConn.QueryRow(q, []byte(bucket), []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)
}
var row *sql.Row
if newValue == nil {
q := `
WITH matching_key AS (
SELECT * FROM pathdata WHERE bucket = $1::BYTEA AND fullpath = $2::BYTEA
), updated AS (
DELETE FROM pathdata
USING matching_key mk
WHERE pathdata.metadata = $3::BYTEA
AND pathdata.bucket = mk.bucket
AND pathdata.fullpath = mk.fullpath
RETURNING 1
)
SELECT EXISTS(SELECT 1 FROM matching_key) AS key_present, EXISTS(SELECT 1 FROM updated) AS value_updated
`
row = client.pgConn.QueryRow(q, []byte(bucket), []byte(key), []byte(oldValue))
} else {
q := `
WITH matching_key AS (
SELECT * FROM pathdata WHERE bucket = $1::BYTEA AND fullpath = $2::BYTEA
), updated AS (
UPDATE pathdata
SET metadata = $4::BYTEA
FROM matching_key mk
WHERE pathdata.metadata = $3::BYTEA
AND pathdata.bucket = mk.bucket
AND pathdata.fullpath = mk.fullpath
RETURNING 1
)
SELECT EXISTS(SELECT 1 FROM matching_key) AS key_present, EXISTS(SELECT 1 FROM updated) AS value_updated;
`
row = client.pgConn.QueryRow(q, []byte(bucket), []byte(key), []byte(oldValue), []byte(newValue))
}
var keyPresent, valueUpdated bool
err = row.Scan(&keyPresent, &valueUpdated)
if err != nil {
return Error.Wrap(err)
}
if !keyPresent {
return storage.ErrKeyNotFound.New("%q", key)
}
if !valueUpdated {
return storage.ErrValueChanged.New("%q", key)
}
return nil
}