mirror of
https://github.com/prometheus/prometheus.git
synced 2024-12-26 06:04:05 -08:00
a2e4439086
Allows to use graphite over tcp or udp. Metrics labels
and values are used to construct a valid Graphite path
in a way that will allow us to eventually read them back
and reconstruct the metrics.
For example, this metric:
model.Metric{
model.MetricNameLabel: "test:metric",
"testlabel": "test:value",
"testlabel2": "test:value",
)
Will become:
test:metric.testlabel=test:value.testlabel2=test:value
escape.go takes care of escaping values to match Graphite
character set, it basically uses percent-encoding as a fallback
wich will work pretty will in the graphite/grafana world.
The remote storage module also has an optional 'prefix' parameter
to prefix all metrics with a path (for example, 'prometheus.').
Graphite URLs are simply in the form tcp://host:port or
udp://host:port.
104 lines
3.9 KiB
Go
104 lines
3.9 KiB
Go
// Copyright 2015 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 graphite
|
|
|
|
import (
|
|
"bytes"
|
|
"fmt"
|
|
"strings"
|
|
|
|
"github.com/prometheus/common/model"
|
|
)
|
|
|
|
const (
|
|
// From https://github.com/graphite-project/graphite-web/blob/master/webapp/graphite/render/grammar.py#L83
|
|
symbols = "(){},=.'\"\\"
|
|
printables = ("0123456789abcdefghijklmnopqrstuvwxyz" +
|
|
"ABCDEFGHIJKLMNOPQRSTUVWXYZ" +
|
|
"!\"#$%&\\'()*+,-./:;<=>?@[\\]^_`{|}~")
|
|
)
|
|
|
|
// Graphite doesn't support tags, so label names and values must be
|
|
// encoded into the metric path. The list of characters that are usable
|
|
// with Graphite is rather fuzzy. One 'source of truth' might be the grammar
|
|
// used to parse requests in the webapp:
|
|
// https://github.com/graphite-project/graphite-web/blob/master/webapp/graphite/render/grammar.py#L83
|
|
// The list of valid symbols is defined as:
|
|
// legal = printables - symbols + escaped(symbols)
|
|
//
|
|
// The default storage backend for Graphite (whisper) stores data
|
|
// in filenames, so we also need to use only valid filename characters.
|
|
// Fortunately on UNIX only '/' isn't, and Windows is completely unsupported
|
|
// by Graphite: http://graphite.readthedocs.org/en/latest/install.html#windows-users
|
|
|
|
// escape escapes a model.LabelValue into runes allowed in Graphite. The runes
|
|
// allowed in Graphite are all single-byte. This function encodes the arbitrary
|
|
// byte sequence found in this TagValue in way very similar to the traditional
|
|
// percent-encoding (https://en.wikipedia.org/wiki/Percent-encoding):
|
|
//
|
|
// - The string that underlies TagValue is scanned byte by byte.
|
|
//
|
|
// - If a byte represents a legal Graphite rune with the exception of '%', '/',
|
|
// '=' and '.', that byte is directly copied to the resulting byte slice.
|
|
// % is used for percent-encoding of other bytes.
|
|
// / is not usable in filenames.
|
|
// = is used when generating the path to associate values to labels.
|
|
// . already means something for Graphite and thus can't be used in a value.
|
|
//
|
|
// - If the byte is any of (){},=.'"\, then a '\' will be prepended to it. We
|
|
// do not percent-encode them since they are explicitly usable in this
|
|
// way in Graphite.
|
|
//
|
|
// - All other bytes are replaced by '%' followed by two bytes containing the
|
|
// uppercase ASCII representation of their hexadecimal value.
|
|
//
|
|
// This encoding allows to save arbitrary Go strings in Graphite. That's
|
|
// required because Prometheus label values can contain anything. Using
|
|
// percent encoding makes it easy to unescape, even in javascript.
|
|
//
|
|
// Examples:
|
|
//
|
|
// "foo-bar-42" -> "foo-bar-42"
|
|
//
|
|
// "foo_bar%42" -> "foo_bar%2542"
|
|
//
|
|
// "http://example.org:8080" -> "http:%2F%2Fexample%2Eorg:8080"
|
|
//
|
|
// "Björn's email: bjoern@soundcloud.com" ->
|
|
// "Bj%C3%B6rn's%20email:%20bjoern%40soundcloud.com"
|
|
//
|
|
// "日" -> "%E6%97%A5"
|
|
func escape(tv model.LabelValue) string {
|
|
length := len(tv)
|
|
result := bytes.NewBuffer(make([]byte, 0, length))
|
|
for i := 0; i < length; i++ {
|
|
b := tv[i]
|
|
switch {
|
|
// . is reserved by graphite, % is used to escape other bytes.
|
|
case b == '.' || b == '%' || b == '/' || b == '=':
|
|
fmt.Fprintf(result, "%%%X", b)
|
|
// These symbols are ok only if backslash escaped.
|
|
case strings.IndexByte(symbols, b) != -1:
|
|
result.WriteString("\\" + string(b))
|
|
// These are all fine.
|
|
case strings.IndexByte(printables, b) != -1:
|
|
result.WriteByte(b)
|
|
// Defaults to percent-encoding.
|
|
default:
|
|
fmt.Fprintf(result, "%%%X", b)
|
|
}
|
|
}
|
|
return result.String()
|
|
}
|