prometheus/storage/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

77 lines
2.3 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 storage
// RecordDecoder decodes each key-value pair in the database. The protocol
// around it makes the assumption that the underlying implementation is
// concurrency safe.
type RecordDecoder interface {
DecodeKey(in interface{}) (out interface{}, err error)
DecodeValue(in interface{}) (out interface{}, err error)
}
// FilterResult describes the record matching and scanning behavior for the
// database.
type FilterResult int
const (
// Stop scanning the database.
Stop FilterResult = iota
// Skip this record but continue scanning.
Skip
// Accept this record for the Operator.
Accept
)
func (f FilterResult) String() string {
switch f {
case Stop:
return "STOP"
case Skip:
return "SKIP"
case Accept:
return "ACCEPT"
}
panic("unknown")
}
// OperatorError is used for storage operations upon errors that may or may not
// be continuable.
type OperatorError struct {
Error error
Continuable bool
}
// RecordFilter is responsible for controlling the behavior of the database scan
// process and determines the disposition of various records.
//
// The protocol around it makes the assumption that the underlying
// implementation is concurrency safe.
type RecordFilter interface {
// Filter receives the key and value as decoded from the RecordDecoder type.
Filter(key, value interface{}) (filterResult FilterResult)
}
// RecordOperator is responsible for taking action upon each entity that is
// passed to it.
//
// The protocol around it makes the assumption that the underlying
// implementation is concurrency safe.
type RecordOperator interface {
// Take action on a given record. If the action returns an error, the entire
// scan process stops.
Operate(key, value interface{}) (err *OperatorError)
}