prometheus/storage/raw/interface.go
Bjoern Rabenstein 6bc083f38b Major code cleanup in storage.
- Mostly docstring fixed/additions.
  (Please review these carefully, since most of them were missing, I
  had to guess them from an outsider's perspective. (Which on the
  other hand proves how desperately required many of these docstrings
  are.))

- Removed all uses of new(...) to meet our own style guide (draft).

- Fixed all other 'go vet' and 'golint' issues (except those that are
  not fixable (i.e. caused by bugs in or by design of 'go vet' and
  'golint')).

- Some trivial refactorings, like reorder functions, minor renames, ...

- Some slightly less trivial refactoring, mostly to reduce code
  duplication by embedding types instead of writing many explicit
  forwarders.

- Cleaned up the interface structure a bit. (Most significant probably
  the removal of the View-like methods from MetricPersistenc. Now they
  are only in View and not duplicated anymore.)

- Removed dead code. (Probably not all of it, but it's a first
  step...)

- Fixed a leftover in storage/metric/end_to_end_test.go (that made
  some parts of the code never execute (incidentally, those parts
  were broken (and I fixed them, too))).

Change-Id: Ibcac069940d118a88f783314f5b4595dce6641d5
2014-02-27 15:22:37 +01:00

86 lines
3.1 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"
)
// Database provides a few very basic methods to manage a database and inquire
// its state.
type Database interface {
// Close reaps all of the underlying system resources associated with
// this database. For databases that don't need that kind of clean-up,
// it is implemented as a no-op (so that clients don't need to reason
// and always call Close 'just in case').
Close() error
// State reports the state of the database as a DatabaseState object.
State() *DatabaseState
// Size returns the total size of the database in bytes. The number may
// be an approximation, depending on the underlying database type.
Size() (uint64, error)
}
// ForEacher is implemented by databases that can be iterated through.
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)
}
// Pruner is implemented by a database that can be pruned in some way.
type Pruner interface {
Prune()
}
// Persistence models a key-value store for bytes that supports various
// additional operations.
type Persistence interface {
Database
ForEacher
// Has informs the user whether a given key exists in the database.
Has(key proto.Message) (bool, error)
// Get populates 'value' with the value of 'key', if present, in which
// case 'present' is returned as true.
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)
}