go-ethereum/metrics/prometheus/collector_test.go
Martin HS 9045b79bc2
metrics, cmd/geth: change init-process of metrics (#30814)
This PR modifies how the metrics library handles `Enabled`: previously,
the package `init` decided whether to serve real metrics or just
dummy-types.

This has several drawbacks: 
- During pkg init, we need to determine whether metrics are enabled or
not. So we first hacked in a check if certain geth-specific
commandline-flags were enabled. Then we added a similar check for
geth-env-vars. Then we almost added a very elaborate check for
toml-config-file, plus toml parsing.

- Using "real" types and dummy types interchangeably means that
everything is hidden behind interfaces. This has a performance penalty,
and also it just adds a lot of code.

This PR removes the interface stuff, uses concrete types, and allows for
the setting of Enabled to happen later. It is still assumed that
`metrics.Enable()` is invoked early on.

The somewhat 'heavy' operations, such as ticking meters and exp-decay,
now checks the enable-flag to prevent resource leak.

The change may be large, but it's mostly pretty trivial, and from the
last time I gutted the metrics, I ensured that we have fairly good test
coverage.

---------

Co-authored-by: Felix Lange <fjl@twurst.com>
2024-12-10 13:27:29 +01:00

66 lines
1.8 KiB
Go

// Copyright 2023 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
package prometheus
import (
"fmt"
"os"
"strings"
"testing"
"github.com/ethereum/go-ethereum/metrics"
"github.com/ethereum/go-ethereum/metrics/internal"
)
func TestMain(m *testing.M) {
metrics.Enable()
os.Exit(m.Run())
}
func TestCollector(t *testing.T) {
var (
c = newCollector()
want string
)
internal.ExampleMetrics().Each(func(name string, i interface{}) {
c.Add(name, i)
})
if wantB, err := os.ReadFile("./testdata/prometheus.want"); err != nil {
t.Fatal(err)
} else {
want = string(wantB)
}
if have := c.buff.String(); have != want {
t.Logf("have\n%v", have)
t.Logf("have vs want:\n%v", findFirstDiffPos(have, want))
t.Fatalf("unexpected collector output")
}
}
func findFirstDiffPos(a, b string) string {
yy := strings.Split(b, "\n")
for i, x := range strings.Split(a, "\n") {
if i >= len(yy) {
return fmt.Sprintf("have:%d: %s\nwant:%d: <EOF>", i, x, i)
}
if y := yy[i]; x != y {
return fmt.Sprintf("have:%d: %s\nwant:%d: %s", i, x, i, y)
}
}
return ""
}