prometheus/tsdb/example_test.go
Arve Knudsen 6daee89e5f
Add context argument to Querier.Select (#12660)
Signed-off-by: Arve Knudsen <arve.knudsen@gmail.com>
2023-09-12 12:37:38 +02:00

105 lines
2.7 KiB
Go

// Copyright 2021 The Prometheus Authors
// 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 tsdb
import (
"context"
"fmt"
"math"
"os"
"time"
"github.com/prometheus/prometheus/model/labels"
"github.com/prometheus/prometheus/tsdb/chunkenc"
)
func Example() {
// Create a random dir to work in. Open() doesn't require a pre-existing dir, but
// we want to make sure not to make a mess where we shouldn't.
dir, err := os.MkdirTemp("", "tsdb-test")
noErr(err)
// Open a TSDB for reading and/or writing.
db, err := Open(dir, nil, nil, DefaultOptions(), nil)
noErr(err)
// Open an appender for writing.
app := db.Appender(context.Background())
series := labels.FromStrings("foo", "bar")
// Ref is 0 for the first append since we don't know the reference for the series.
ref, err := app.Append(0, series, time.Now().Unix(), 123)
noErr(err)
// Another append for a second later.
// Re-using the ref from above since it's the same series, makes append faster.
time.Sleep(time.Second)
_, err = app.Append(ref, series, time.Now().Unix(), 124)
noErr(err)
// Commit to storage.
err = app.Commit()
noErr(err)
// In case you want to do more appends after app.Commit(),
// you need a new appender.
app = db.Appender(context.Background())
// ... adding more samples.
// Open a querier for reading.
querier, err := db.Querier(math.MinInt64, math.MaxInt64)
noErr(err)
ss := querier.Select(context.Background(), false, nil, labels.MustNewMatcher(labels.MatchEqual, "foo", "bar"))
for ss.Next() {
series := ss.At()
fmt.Println("series:", series.Labels().String())
it := series.Iterator(nil)
for it.Next() == chunkenc.ValFloat {
_, v := it.At() // We ignore the timestamp here, only to have a predictable output we can test against (below)
fmt.Println("sample", v)
}
fmt.Println("it.Err():", it.Err())
}
fmt.Println("ss.Err():", ss.Err())
ws := ss.Warnings()
if len(ws) > 0 {
fmt.Println("warnings:", ws)
}
err = querier.Close()
noErr(err)
// Clean up any last resources when done.
err = db.Close()
noErr(err)
err = os.RemoveAll(dir)
noErr(err)
// Output:
// series: {foo="bar"}
// sample 123
// sample 124
// it.Err(): <nil>
// ss.Err(): <nil>
}
func noErr(err error) {
if err != nil {
panic(err)
}
}