feature: [vmalert] support multi-doc yaml parsing

app/vmalert/config/config.go

@@ -1,9 +1,11 @@
 package config
 
 import (
+	"bytes"
 	"crypto/md5"
 	"fmt"
 	"hash/fnv"
+	"maps"
 	"net/url"
 	"sort"
 	"strings"
@@ -48,6 +50,14 @@ type Group struct {
 	XXX map[string]any `yaml:",inline"`
 }
 
+// parseGroup
+// It is used for parseConfig only
+type parseGroup struct {
+	Groups []Group `yaml:"groups"`
+	// Catches all undefined fields and must be empty after parsing.
+	XXX map[string]any `yaml:",inline"`
+}
+
 // UnmarshalYAML implements the yaml.Unmarshaler interface.
 func (g *Group) UnmarshalYAML(unmarshal func(any) error) error {
 	type group Group
@@ -298,15 +308,23 @@ func parseConfig(data []byte) ([]Group, error) {
 	if err != nil {
 		return nil, fmt.Errorf("cannot expand environment vars: %w", err)
 	}
-	g := struct {
-		Groups []Group `yaml:"groups"`
-		// Catches all undefined fields and must be empty after parsing.
-		XXX map[string]any `yaml:",inline"`
-	}{}
-	err = yaml.Unmarshal(data, &g)
+
+	// https://gettaurus.org/docs/YAMLTutorial/#YAML-Multi-Documents
+	multiDocs := bytes.Split(data, []byte("\n---\n"))
+	g := parseGroup{
+		XXX: make(map[string]any),
+	}
+
+	for _, doc := range multiDocs {
+		var pg parseGroup
+		err = yaml.Unmarshal(doc, &pg)
 		if err != nil {
 			return nil, err
 		}
+		g.Groups = append(g.Groups, pg.Groups...)
+		maps.Copy(g.XXX, pg.XXX)
+	}
+
 	return g.Groups, checkOverflow(g.XXX, "config")
 }
 

app/vmalert/config/config_test.go

@@ -79,6 +79,7 @@ func TestParse_Failure(t *testing.T) {
 
 	f([]string{"testdata/rules/rules_interval_bad.rules"}, "eval_offset should be smaller than interval")
 	f([]string{"testdata/rules/rules0-bad.rules"}, "unexpected token")
+	f([]string{"testdata/rules/rules-multi-doc-bad.rules"}, "unknown fields in config: invalid-field-1, invalid-field-2, invalid-field-3")
 	f([]string{"testdata/dir/rules0-bad.rules"}, "error parsing annotation")
 	f([]string{"testdata/dir/rules1-bad.rules"}, "duplicate in file")
 	f([]string{"testdata/dir/rules2-bad.rules"}, "function \"unknown\" not defined")

app/vmalert/config/testdata/rules/rules-multi-doc-bad.rules

@@ -0,0 +1,30 @@
+groups:
+  - name: groupTest
+    rules:
+      - alert: VMRows
+        for: 1ms
+        expr: vm_rows > 0
+        labels:
+          label: bar
+          host: "{{ $labels.instance }}"
+        annotations:
+          summary: "{{ $value }}"
+invalid-field-1: invalid-value-1
+invalid-field-2: invalid-value-2
+---
+groups:
+  - name: TestGroup
+    interval: 2s
+    concurrency: 2
+    type: graphite
+    rules:
+      - alert: Conns
+        expr: filterSeries(sumSeries(host.receiver.interface.cons),'last','>', 500)
+        for: 3m
+
+        annotations:
+          summary: Too high connection number for {{$labels.instance}}
+          description: "It is {{ $value }} connections for {{$labels.instance}}"
+invalid-field-2: invalid-value-2
+invalid-field-3: invalid-value-3
+

app/vmalert/config/testdata/rules/rules-multi-doc-good.rules

@@ -0,0 +1,39 @@
+
+---
+groups:
+  - name: groupTest
+    rules:
+      - alert: VMRows
+        for: 1ms
+        expr: vm_rows > 0
+        labels:
+          label: bar
+          host: "{{ $labels.instance }}"
+        annotations:
+          summary: "{{ $value }}"
+---
+groups:
+  - name: TestGroup
+    interval: 2s
+    concurrency: 2
+    type: graphite
+    rules:
+      - alert: Conns
+        expr: filterSeries(sumSeries(host.receiver.interface.cons),'last','>', 500)
+        for: 3m
+
+        annotations:
+          summary: Too high connection number for {{$labels.instance}}
+          description: "It is {{ $value }} connections for {{$labels.instance}}"
+  - name: TestGroupPromMixed
+    interval: 2s
+    concurrency: 2
+    type: prometheus
+    eval_delay: 30s
+    rules:
+      - alert: Conns
+        expr: sum(vm_tcplistener_conns) by (instance) > 1
+        for: 3m
+        annotations:
+          summary: Too high connection number for {{$labels.instance}}
+          description: "It is {{ $value }} connections for {{$labels.instance}}"

docs/changelog/CHANGELOG.md

@@ -24,6 +24,7 @@ See also [LTS releases](https://docs.victoriametrics.com/lts-releases/).
 
 * FEATURE [stream aggregation](https://docs.victoriametrics.com/stream-aggregation/): perform deduplication for all received data when specifying `-streamAggr.dedupInterval` or `-remoteWrite.streamAggr.dedupInterval` command-line flags are set. Previously, if the `-remoteWrite.streamAggr.config` or `-streamAggr.config` is set, only series that matched aggregation config were deduplicated. See [this issue](https://github.com/VictoriaMetrics/VictoriaMetrics/pull/6711#issuecomment-2288361213) for details.
 * FEATURE: all VictoriaMetrics [enterprise](https://docs.victoriametrics.com/enterprise/) components: add support of hot-reload for license key supplied by `-licenseFile` command-line flag.
+* FEATURE: [vmalert](https://docs.victoriametrics.com/vmalert/): support multi-doc yaml parsing. See [this issue](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/6753). 
 * FEATURE: [vmgateway](https://docs.victoriametrics.com/vmgateway/): allow disabling `Bearer` prefix enforcement for authentication header. This is useful for cases when identity token is used instead of access token.
 * FEATURE: [vmgateway](https://docs.victoriametrics.com/vmgateway/): support parting `vm_access` claims in string format. This is useful for cases when identity provider does not support mapping claims to JSON format.
 * FEATURE: [Single-node VictoriaMetrics](https://docs.victoriametrics.com/) and `vmstorage` in [VictoriaMetrics cluster](https://docs.victoriametrics.com/cluster-victoriametrics/): Adds new metrics for data ingestion: `vm_rows_received_by_storage_total`, `vm_rows_ignored_total{reason="nan_value"}`, `vm_rows_ignored_total{reason="invalid_raw_metric_name"}`, `vm_rows_ignored_total{reason="hourly_limit_exceeded"}`, `vm_rows_ignored_total{reason="daily_limit_exceeded"}`. See this [PR](https://github.com/VictoriaMetrics/VictoriaMetrics/pull/6663) for details.