prometheus/storage/raw/leveldb/test/fixtures.go
Matt T. Proud a73f061d3c Persist solely Protocol Buffers.
An design question was open for me in the beginning was whether to
serialize other types to disk, but Protocol Buffers quickly won out,
which allows us to drop support for other types.  This is a good
start to cleaning up a lot of cruft in the storage stack and
can let us eventually decouple the various moving parts into
separate subsystems for easier reasoning.

This commit is not strictly required, but it is a start to making
the rest a lot more enjoyable to interact with.
2013-06-08 11:02:35 +02:00

113 lines
2.7 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 test
import (
"code.google.com/p/goprotobuf/proto"
"github.com/prometheus/prometheus/storage/raw/leveldb"
"github.com/prometheus/prometheus/utility/test"
)
const (
cacheCapacity = 0
bitsPerBloomFilterEncoded = 0
)
type (
// Pair models a prospective (key, value) double that will be committed to
// a database.
Pair interface {
Get() (key, value proto.Message)
}
// Pairs models a list of Pair for disk committing.
Pairs []Pair
// Preparer readies a LevelDB store for a given raw state given the fixtures
// definitions passed into it.
Preparer interface {
// Prepare furnishes the database and returns its path along with any
// encountered anomalies.
Prepare(namespace string, f FixtureFactory) test.TemporaryDirectory
}
FixtureFactory interface {
// HasNext indicates whether the FixtureFactory has more pending fixture
// data to build.
HasNext() (has bool)
// Next emits the next (key, value) double for storage.
Next() (key, value proto.Message)
}
preparer struct {
tester test.Tester
}
cassetteFactory struct {
index int
count int
pairs Pairs
}
)
func (p preparer) Prepare(n string, f FixtureFactory) (t test.TemporaryDirectory) {
t = test.NewTemporaryDirectory(n, p.tester)
persistence, err := leveldb.NewLevelDBPersistence(t.Path(), cacheCapacity, bitsPerBloomFilterEncoded)
if err != nil {
defer t.Close()
p.tester.Fatal(err)
}
defer persistence.Close()
for f.HasNext() {
key, value := f.Next()
err = persistence.Put(key, value)
if err != nil {
defer t.Close()
p.tester.Fatal(err)
}
}
return
}
func (f cassetteFactory) HasNext() bool {
return f.index < f.count
}
func (f *cassetteFactory) Next() (key, value proto.Message) {
key, value = f.pairs[f.index].Get()
f.index++
return
}
// NewPreparer creates a new Preparer for use in testing scenarios.
func NewPreparer(t test.Tester) Preparer {
return preparer{t}
}
// NewCassetteFactory builds a new FixtureFactory that uses Pairs as the basis
// for generated fixture data.
func NewCassetteFactory(pairs Pairs) FixtureFactory {
return &cassetteFactory{
pairs: pairs,
count: len(pairs),
}
}