prometheus/storage/raw/interface.go
Matt T. Proud 4a87c002e8 Update low-level i'faces to reflect wireformats.
This commit fixes a critique of the old storage API design, whereby
the input parameters were always as raw bytes and never Protocol
Buffer messages that encapsulated the data, meaning every place a
read or mutation was conducted needed to manually perform said
translations on its own.  This is taxing.

Change-Id: I4786938d0d207cefb7782bd2bd96a517eead186f
2013-09-04 17:13:58 +02:00

71 lines
2.4 KiB
Go

// Copyright 2013 Prometheus Team
// 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 raw
import (
"code.google.com/p/goprotobuf/proto"
"github.com/prometheus/prometheus/storage"
)
type ForEacher interface {
// ForEach is responsible for iterating through all records in the database
// until one of the following conditions are met:
//
// 1.) A system anomaly in the database scan.
// 2.) The last record in the database is reached.
// 3.) A FilterResult of STOP is emitted by the Filter.
//
// Decoding errors for an entity cause that entity to be skipped.
ForEach(storage.RecordDecoder, storage.RecordFilter, storage.RecordOperator) (scannedEntireCorpus bool, err error)
}
// Persistence models a key-value store for bytes that supports various
// additional operations.
type Persistence interface {
ForEacher
// Close reaps all of the underlying system resources associated with this
// persistence.
Close() error
// Has informs the user whether a given key exists in the database.
Has(key proto.Message) (bool, error)
// Get retrieves the key from the database if it exists or returns nil if
// it is absent.
Get(key, value proto.Message) (present bool, err error)
// Drop removes the key from the database.
Drop(key proto.Message) error
// Put sets the key to a given value.
Put(key, value proto.Message) error
// Commit applies the Batch operations to the database.
Commit(Batch) error
}
// Batch models a pool of mutations for the database that can be committed
// en masse. The interface implies no protocol around the atomicity of
// effectuation.
type Batch interface {
// Close reaps all of the underlying system resources associated with this
// batch mutation.
Close()
// Put follows the same protocol as Persistence.Put.
Put(key, value proto.Message)
// Drop follows the same protocol as Persistence.Drop.
Drop(key proto.Message)
}
type Pruner interface {
Prune() (noop bool, err error)
}