feat: support regular expressions in receiver configs

This allows using the `keep_re` and `strip_re` keys to specify which
receivers should be shown in the dashboard. This makes it easy to select
groups of receivers based on naming conventions.

cmd/karma/tests/testscript/059_log_full_config_env.txt

@@ -221,9 +221,11 @@ level=info msg="receivers:"
 level=info msg="  keep:"
 level=info msg="    - keep1"
 level=info msg="    - keep2"
+level=info msg="  keep_re: []"
 level=info msg="  strip:"
 level=info msg="    - strip1"
 level=info msg="    - strip2"
+level=info msg="  strip_re: []"
 level=info msg="silences:"
 level=info msg="  expired: 1s"
 level=info msg="  comments:"

cmd/karma/tests/testscript/060_log_full_config_file.txt

@@ -257,9 +257,11 @@ level=info msg="receivers:"
 level=info msg="  keep:"
 level=info msg="    - keep1"
 level=info msg="    - keep2"
+level=info msg="  keep_re: []"
 level=info msg="  strip:"
 level=info msg="    - strip1"
 level=info msg="    - strip2"
+level=info msg="  strip_re: []"
 level=info msg="silences:"
 level=info msg="  expired: 5m0s"
 level=info msg="  comments:"

cmd/karma/tests/testscript/065_proxy-with-readonly.txt

@@ -113,7 +113,9 @@ level=info msg="  requests: false"
 level=info msg="  timestamp: false"
 level=info msg="receivers:"
 level=info msg="  keep: []"
+level=info msg="  keep_re: []"
 level=info msg="  strip: []"
+level=info msg="  strip_re: []"
 level=info msg="silences:"
 level=info msg="  expired: 10m0s"
 level=info msg="  comments:"

cmd/karma/tests/testscript/066_proxy.txt

@@ -113,7 +113,9 @@ level=info msg="  requests: false"
 level=info msg="  timestamp: false"
 level=info msg="receivers:"
 level=info msg="  keep: []"
+level=info msg="  keep_re: []"
 level=info msg="  strip: []"
+level=info msg="  strip_re: []"
 level=info msg="silences:"
 level=info msg="  expired: 10m0s"
 level=info msg="  comments:"

cmd/karma/tests/testscript/067_readonly.txt

@@ -113,7 +113,9 @@ level=info msg="  requests: false"
 level=info msg="  timestamp: false"
 level=info msg="receivers:"
 level=info msg="  keep: []"
+level=info msg="  keep_re: []"
 level=info msg="  strip: []"
+level=info msg="  strip_re: []"
 level=info msg="silences:"
 level=info msg="  expired: 10m0s"
 level=info msg="  comments:"

cmd/karma/tests/testscript/070_upper_case_keys.txt

@@ -123,7 +123,9 @@ level=info msg="  requests: false"
 level=info msg="  timestamp: false"
 level=info msg="receivers:"
 level=info msg="  keep: []"
+level=info msg="  keep_re: []"
 level=info msg="  strip: []"
+level=info msg="  strip_re: []"
 level=info msg="silences:"
 level=info msg="  expired: 10m0s"
 level=info msg="  comments:"

cmd/karma/tests/testscript/097_proxy_url_config.txt

@@ -113,7 +113,9 @@ level=info msg="  requests: false"
 level=info msg="  timestamp: false"
 level=info msg="receivers:"
 level=info msg="  keep: []"
+level=info msg="  keep_re: []"
 level=info msg="  strip: []"
+level=info msg="  strip_re: []"
 level=info msg="silences:"
 level=info msg="  expired: 10m0s"
 level=info msg="  comments:"

cmd/karma/tests/testscript/112_flag_defaultAlertmanagers.txt

@@ -92,7 +92,9 @@ level=info msg="  requests: false"
 level=info msg="  timestamp: false"
 level=info msg="receivers:"
 level=info msg="  keep: []"
+level=info msg="  keep_re: []"
 level=info msg="  strip: []"
+level=info msg="  strip_re: []"
 level=info msg="silences:"
 level=info msg="  expired: 10m0s"
 level=info msg="  comments:"

internal/alertmanager/dedup.go

@@ -37,7 +37,13 @@ func DedupAlerts() []models.AlertGroup {
 				alert := alert // scopelint pin
 				// remove all alerts for receiver(s) that the user doesn't
 				// want to see in the UI
-				if transform.StripReceivers(config.Config.Receivers.Keep, config.Config.Receivers.Strip, alert.Receiver) {
+				if transform.StripReceivers(
+					config.Config.Receivers.Keep,
+					config.Config.Receivers.Strip,
+					config.Config.Receivers.CompiledKeepRegex,
+					config.Config.Receivers.CompiledStripRegex,
+					alert.Receiver,
+				) {
 					continue
 				}
 

internal/config/config.go

@@ -126,8 +126,12 @@ func SetupFlags(f *pflag.FlagSet) {
 
 	f.StringSlice("receivers.keep", []string{},
 		"List of receivers to keep, all alerts with different receivers will be ignored")
+	f.StringSlice("receivers.keep_re", []string{},
+		"List of regular expressions to keep matching receivers, all other receivers will be ignored")
 	f.StringSlice("receivers.strip", []string{},
 		"List of receivers to not display alerts for")
+	f.StringSlice("receivers.strip_re", []string{},
+		"List of regular expressions to ignore matching receivers")
 
 	f.Duration("silences.expired", time.Minute*10, "Maximum age of expired silences to show on active alerts")
 	f.StringSlice("silenceForm.strip.labels", []string{}, "List of labels to ignore when auto-filling silence form from alerts")
@@ -413,6 +417,22 @@ func (config *configSchema) Read(flags *pflag.FlagSet) (string, error) {
 		}
 	}
 
+	config.Receivers.CompiledKeepRegex = make([]*regexp.Regexp, len(config.Receivers.KeepRegex))
+	for i, keepRegex := range config.Receivers.KeepRegex {
+		config.Receivers.CompiledKeepRegex[i], err = regex.CompileAnchored(keepRegex)
+		if err != nil {
+			return "", fmt.Errorf("keep regex rule '%s' is invalid: %w", keepRegex, err)
+		}
+	}
+
+	config.Receivers.CompiledStripRegex = make([]*regexp.Regexp, len(config.Receivers.StripRegex))
+	for i, stripRegex := range config.Receivers.KeepRegex {
+		config.Receivers.CompiledStripRegex[i], err = regex.CompileAnchored(stripRegex)
+		if err != nil {
+			return "", fmt.Errorf("strip regex rule '%s' is invalid: %w", stripRegex, err)
+		}
+	}
+
 	if !slices.StringInSlice([]string{"disabled", "startsAt", "label"}, config.Grid.Sorting.Order) {
 		return "", fmt.Errorf("invalid grid.sorting.order value '%s', allowed options: disabled, startsAt, label", config.Grid.Sorting.Order)
 	}

internal/config/models.go

@@ -195,8 +195,12 @@ type configSchema struct {
 		Timestamp bool
 	}
 	Receivers struct {
-		Keep  []string
-		Strip []string
+		Keep               []string
+		KeepRegex          []string         `yaml:"keep_re" koanf:"keep_re"`
+		CompiledKeepRegex  []*regexp.Regexp `yaml:"-"`
+		Strip              []string
+		StripRegex         []string         `yaml:"strip_re" koanf:"strip_re"`
+		CompiledStripRegex []*regexp.Regexp `yaml:"-"`
 	}
 	Silences struct {
 		Expired  time.Duration

internal/transform/strip.go

@@ -40,13 +40,14 @@ func StripLables(keptLabels, ignoredLabels []string, keptLabelsRegex, ignoredLab
 
 // StripReceivers allows filtering all alerts for specified receiver(s)
 // it will return true if alert uses receiver that should be stripped
-func StripReceivers(keptReceivers, ignoredReceivers []string, alertReceiver string) bool {
-	// true if we keep by default
-	keepAll := len(keptReceivers) == 0
-	// is this receiver on the whitelist ?
-	inKeep := slices.StringInSlice(keptReceivers, alertReceiver)
-	// is this receiver on the blacklist ?
-	inStrip := slices.StringInSlice(ignoredReceivers, alertReceiver)
+func StripReceivers(keptReceivers, ignoredReceivers []string, keptReceiversRegex, ignoredReceiversRegex []*regexp.Regexp, alertReceiver string) bool {
+	// empty keep lists means keep everything by default
+	keepAll := len(keptReceivers) == 0 && len(keptReceiversRegex) == 0
+	// is explicitly marked to be kept
+	inKeep := slices.StringInSlice(keptReceivers, alertReceiver) || slices.MatchesAnyRegex(alertReceiver, keptReceiversRegex)
+	// is explicitly marked to be stripped
+	inStrip := slices.StringInSlice(ignoredReceivers, alertReceiver) || slices.MatchesAnyRegex(alertReceiver, ignoredReceiversRegex)
+
 	if (keepAll || inKeep) && !inStrip {
 		return false
 	}

internal/transform/strip_test.go

@@ -201,6 +201,8 @@ func getCompiledRegex(regexes []string, t *testing.T) []*regexp.Regexp {
 type stripReceiverTest struct {
 	strip    []string
 	keep     []string
+	stripRe  []string
+	keepRe   []string
 	receiver string
 	stripped bool
 }
@@ -209,44 +211,82 @@ var stripReceiverTests = []stripReceiverTest{
 	{
 		strip:    []string{},
 		keep:     []string{},
+		stripRe:  []string{},
+		keepRe:   []string{},
 		receiver: "default",
 		stripped: false,
 	},
 	{
 		strip:    []string{"default"},
 		keep:     []string{},
+		stripRe:  []string{},
+		keepRe:   []string{},
 		receiver: "default",
 		stripped: true,
 	},
 	{
 		strip:    []string{"default"},
 		keep:     []string{"default"},
+		stripRe:  []string{},
+		keepRe:   []string{},
 		receiver: "default",
 		stripped: true,
 	},
 	{
 		strip:    []string{},
 		keep:     []string{"default"},
+		stripRe:  []string{},
+		keepRe:   []string{},
 		receiver: "default",
 		stripped: false,
 	},
 	{
 		strip:    []string{"foo", "bar"},
 		keep:     []string{},
+		stripRe:  []string{},
+		keepRe:   []string{},
 		receiver: "default",
 		stripped: false,
 	},
 	{
 		strip:    []string{"foo", "default"},
 		keep:     []string{"foo", "bar"},
+		stripRe:  []string{},
+		keepRe:   []string{},
 		receiver: "default",
 		stripped: true,
 	},
+	{
+		strip:    []string{},
+		keep:     []string{},
+		stripRe:  []string{},
+		keepRe:   []string{"default-.+"},
+		receiver: "default-foo",
+		stripped: false,
+	},
+	{
+		strip:    []string{},
+		keep:     []string{},
+		stripRe:  []string{},
+		keepRe:   []string{"default-.+"},
+		receiver: "foo-bar",
+		stripped: true,
+	},
+	{
+		strip:    []string{},
+		keep:     []string{"default-foo"},
+		stripRe:  []string{"default-.+"},
+		keepRe:   []string{},
+		receiver: "default-foo",
+		stripped: true,
+	},
 }
 
 func TestStripReceivers(t *testing.T) {
 	for _, testCase := range stripReceiverTests {
-		stripped := transform.StripReceivers(testCase.keep, testCase.strip, testCase.receiver)
+		keepRegex := getCompiledRegex(testCase.keepRe, t)
+		stripRegex := getCompiledRegex(testCase.keepRe, t)
+		stripped := transform.StripReceivers(testCase.keep, testCase.strip, keepRegex, stripRegex, testCase.receiver)
 		if stripped != testCase.stripped {
 			t.Errorf("StripReceivers failed, expected %v, got %v", testCase.stripped, stripped)
 		}