utils: share the include/exclude regexp flag handling (#2737)

Signed-off-by: Jan-Otto Kröpke <mail@jkroepke.de>
2026-10-17 18:19:04 +02:00 · 2026-10-16 00:07:30 +02:00
parent 34738679a1
commit 81ce8ef79d
18 changed files with 422 additions and 224 deletions
@@ -0,0 +1,99 @@
+// SPDX-License-Identifier: Apache-2.0
+//
+// Copyright 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.
+
+//go:build windows
+
+package utils
+
+import (
+	"fmt"
+	"regexp"
+	"slices"
+
+	"github.com/alecthomas/kingpin/v2"
+	"github.com/prometheus-community/windows_exporter/internal/types"
+)
+
+//nolint:gochecknoglobals
+var (
+	// matchAllExpressions are the expressions of an include filter that matches every name.
+	matchAllExpressions = []string{anchor(".+"), anchor(".*"), types.RegExpAny.String()}
+	// matchNoneExpressions are the expressions of an exclude filter that matches no name.
+	matchNoneExpressions = []string{anchor(""), types.RegExpEmpty.String()}
+)
+
+// anchor wraps expr, so that it must match the whole input.
+func anchor(expr string) string {
+	return "^(?:" + expr + ")$"
+}
+
+// CompileAnchored compiles expr, so that it must match the whole input.
+func CompileAnchored(expr string) (*regexp.Regexp, error) {
+	return regexp.Compile(anchor(expr))
+}
+
+// MustCompileAnchored is like [CompileAnchored], but panics if expr can't be parsed.
+func MustCompileAnchored(expr string) *regexp.Regexp {
+	return regexp.MustCompile(anchor(expr))
+}
+
+// IsMatchAll reports whether re is an include filter that matches every name:
+// the default of an include flag, [types.RegExpAny] or nil, which the New function of
+// a collector replaces with the default.
+func IsMatchAll(re *regexp.Regexp) bool {
+	return re == nil || slices.Contains(matchAllExpressions, re.String())
+}
+
+// IsMatchNone reports whether re is an exclude filter that matches no name:
+// the default of an exclude flag, [types.RegExpEmpty] or nil, which the New function
+// of a collector replaces with the default.
+func IsMatchNone(re *regexp.Regexp) bool {
+	return re == nil || slices.Contains(matchNoneExpressions, re.String())
+}
+
+// anchoredRegexpValue is a [kingpin.Value] which compiles its value with [CompileAnchored].
+type anchoredRegexpValue struct {
+	name   string
+	expr   string
+	target **regexp.Regexp
+}
+
+func (v *anchoredRegexpValue) Set(expr string) error {
+	re, err := CompileAnchored(expr)
+	if err != nil {
+		return fmt.Errorf("%s: %w", v.name, err)
+	}
+
+	v.expr = expr
+	*v.target = re
+
+	return nil
+}
+
+func (v *anchoredRegexpValue) String() string {
+	return v.expr
+}
+
+// RegexpFlag registers the flag name, whose value is a regular expression that
+// must match the whole name. The compiled expression is stored in target when
+// the flags are parsed, including the default and a value from the
+// configuration file. An invalid expression fails the parsing with an error
+// that starts with the name of the flag.
+func RegexpFlag(app *kingpin.Application, name, help, defaultValue string, target **regexp.Regexp) *kingpin.FlagClause {
+	flag := app.Flag(name, help).Default(defaultValue)
+	flag.SetValue(&anchoredRegexpValue{name: name, target: target})
+
+	return flag
+}
@@ -0,0 +1,148 @@
+// SPDX-License-Identifier: Apache-2.0
+//
+// Copyright 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.
+
+//go:build windows
+
+package utils_test
+
+import (
+	"regexp"
+	"testing"
+
+	"github.com/alecthomas/kingpin/v2"
+	"github.com/prometheus-community/windows_exporter/internal/types"
+	"github.com/prometheus-community/windows_exporter/internal/utils"
+	"github.com/stretchr/testify/require"
+)
+
+func TestRegexpFlag(t *testing.T) {
+	t.Parallel()
+
+	for _, tc := range []struct {
+		name         string
+		defaultValue string
+		args         []string
+		want         string
+		matches      []string
+		notMatches   []string
+		matchAll     bool
+		matchNone    bool
+		errorText    string
+	}{
+		{
+			name: "include default", defaultValue: ".+", want: "^(?:.+)$",
+			matches: []string{"a", "svc host"}, notMatches: []string{""}, matchAll: true,
+		},
+		{
+			name: "exclude default", defaultValue: "", want: "^(?:)$",
+			matches: []string{""}, notMatches: []string{"a"}, matchNone: true,
+		},
+		{
+			name: "match all with star", defaultValue: ".+", args: []string{"--collector.test.include=.*"},
+			want: "^(?:.*)$", matchAll: true,
+		},
+		{
+			name: "alternation is anchored as a whole", defaultValue: ".+", args: []string{"--collector.test.include=foo|bar"},
+			want: "^(?:foo|bar)$", matches: []string{"foo", "bar"}, notMatches: []string{"foobar", "xfoo", "barx"},
+		},
+		{
+			name: "default from configuration", defaultValue: "/Microsoft/.+", want: "^(?:/Microsoft/.+)$",
+			matches: []string{"/Microsoft/Windows/Task"}, notMatches: []string{"/Vendor/Task"},
+		},
+		{
+			name: "invalid value names the flag", defaultValue: ".+", args: []string{"--collector.test.include=("},
+			errorText: "collector.test.include: error parsing regexp: missing closing ): `^(?:()$`",
+		},
+		{
+			name: "invalid default names the flag", defaultValue: "[",
+			errorText: "collector.test.include: error parsing regexp",
+		},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+
+			var re *regexp.Regexp
+
+			app := kingpin.New("test", "test")
+			utils.RegexpFlag(app, "collector.test.include", "help", tc.defaultValue, &re)
+
+			_, err := app.Parse(tc.args)
+			if tc.errorText != "" {
+				require.ErrorContains(t, err, tc.errorText)
+
+				return
+			}
+
+			require.NoError(t, err)
+			require.NotNil(t, re)
+			require.Equal(t, tc.want, re.String())
+			require.Equal(t, tc.matchAll, utils.IsMatchAll(re))
+			require.Equal(t, tc.matchNone, utils.IsMatchNone(re))
+
+			for _, name := range tc.matches {
+				require.True(t, re.MatchString(name), name)
+			}
+
+			for _, name := range tc.notMatches {
+				require.False(t, re.MatchString(name), name)
+			}
+		})
+	}
+}
+
+func TestRegexpFlagValue(t *testing.T) {
+	t.Parallel()
+
+	var re *regexp.Regexp
+
+	app := kingpin.New("test", "test")
+	utils.RegexpFlag(app, "collector.test.exclude", "help", "", &re)
+
+	_, err := app.Parse([]string{"--collector.test.exclude=a.b"})
+	require.NoError(t, err)
+	require.Equal(t, "a.b", app.GetFlag("collector.test.exclude").Model().Value.String())
+	require.Equal(t, []string{""}, app.GetFlag("collector.test.exclude").Model().Default)
+}
+
+func TestIsMatchAllAndNone(t *testing.T) {
+	t.Parallel()
+
+	require.True(t, utils.IsMatchAll(nil))
+	require.True(t, utils.IsMatchAll(types.RegExpAny))
+	require.True(t, utils.IsMatchAll(utils.MustCompileAnchored(".+")))
+	require.True(t, utils.IsMatchAll(utils.MustCompileAnchored(".*")))
+	require.False(t, utils.IsMatchAll(utils.MustCompileAnchored("foo")))
+	require.False(t, utils.IsMatchAll(types.RegExpEmpty))
+
+	require.True(t, utils.IsMatchNone(nil))
+	require.True(t, utils.IsMatchNone(types.RegExpEmpty))
+	require.True(t, utils.IsMatchNone(utils.MustCompileAnchored("")))
+	require.False(t, utils.IsMatchNone(utils.MustCompileAnchored("foo")))
+	require.False(t, utils.IsMatchNone(types.RegExpAny))
+}
+
+func TestCompileAnchored(t *testing.T) {
+	t.Parallel()
+
+	re, err := utils.CompileAnchored("svc")
+	require.NoError(t, err)
+	require.True(t, re.MatchString("svc"))
+	require.False(t, re.MatchString("svchost"))
+
+	_, err = utils.CompileAnchored("(")
+	require.Error(t, err)
+
+	require.Panics(t, func() { utils.MustCompileAnchored("(") })
+}