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prometheus/storage/raw/leveldb/iterator.go

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Wrap LevelDB iterator operations behind interface. The LevelDB storage types return an interface type now that wraps around the underlying iterator. This both enhances testability but improves upon, in my opinion, the interface design for the LevelDB iterator. Secondarily, the resource reaping behaviors for the LevelDB iterators have been improved by dropping the externalized io.Closer object. Finally, the iterator provisioning methods provide the option for indicating whether one wants a snapshotted iterator or not.
2013-03-25 09:24:59 +00:00
// 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 leveldb
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
2013-08-29 13:15:22 +00:00
import (
"code.google.com/p/goprotobuf/proto"
)
Wrap LevelDB iterator operations behind interface. The LevelDB storage types return an interface type now that wraps around the underlying iterator. This both enhances testability but improves upon, in my opinion, the interface design for the LevelDB iterator. Secondarily, the resource reaping behaviors for the LevelDB iterators have been improved by dropping the externalized io.Closer object. Finally, the iterator provisioning methods provide the option for indicating whether one wants a snapshotted iterator or not.
2013-03-25 09:24:59 +00:00
// TODO: Evaluate whether to use coding.Encoder for the key and values instead
// raw bytes for consistency reasons.
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
2014-02-14 18:36:27 +00:00
// Iterator provides method to iterate through a leveldb.
Wrap LevelDB iterator operations behind interface. The LevelDB storage types return an interface type now that wraps around the underlying iterator. This both enhances testability but improves upon, in my opinion, the interface design for the LevelDB iterator. Secondarily, the resource reaping behaviors for the LevelDB iterators have been improved by dropping the externalized io.Closer object. Finally, the iterator provisioning methods provide the option for indicating whether one wants a snapshotted iterator or not.
2013-03-25 09:24:59 +00:00
type Iterator interface {
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
2013-08-29 13:15:22 +00:00
Error() error
Valid() bool
SeekToFirst() bool
SeekToLast() bool
Seek(proto.Message) bool
Next() bool
Previous() bool
Key(proto.Message) error
Value(proto.Message) error
Close() error
rawKey() []byte
rawValue() []byte
Wrap LevelDB iterator operations behind interface. The LevelDB storage types return an interface type now that wraps around the underlying iterator. This both enhances testability but improves upon, in my opinion, the interface design for the LevelDB iterator. Secondarily, the resource reaping behaviors for the LevelDB iterators have been improved by dropping the externalized io.Closer object. Finally, the iterator provisioning methods provide the option for indicating whether one wants a snapshotted iterator or not.
2013-03-25 09:24:59 +00:00
}