prometheus/pkg/rulefmt/rulefmt.go

303 lines
8.1 KiB
Go

// Copyright 2017 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 rulefmt
import (
"bytes"
"context"
"io"
"io/ioutil"
"strings"
"time"
"github.com/pkg/errors"
"github.com/prometheus/common/model"
yaml "gopkg.in/yaml.v3"
"github.com/prometheus/prometheus/pkg/timestamp"
"github.com/prometheus/prometheus/promql/parser"
"github.com/prometheus/prometheus/template"
)
// Error represents semantic errors on parsing rule groups.
type Error struct {
Group string
Rule int
RuleName string
Err WrappedError
}
// WrappedError wraps error with the yaml node which can be used to represent
// the line and column numbers of the error.
type WrappedError struct {
err error
node *yaml.Node
nodeAlt *yaml.Node
}
func (err *Error) Error() string {
if err.Err.nodeAlt != nil {
return errors.Wrapf(err.Err.err, "%d:%d: %d:%d: group %q, rule %d, %q", err.Err.node.Line, err.Err.node.Column, err.Err.nodeAlt.Line, err.Err.nodeAlt.Column, err.Group, err.Rule, err.RuleName).Error()
} else if err.Err.node != nil {
return errors.Wrapf(err.Err.err, "%d:%d: group %q, rule %d, %q", err.Err.node.Line, err.Err.node.Column, err.Group, err.Rule, err.RuleName).Error()
}
return errors.Wrapf(err.Err.err, "group %q, rule %d, %q", err.Group, err.Rule, err.RuleName).Error()
}
// RuleGroups is a set of rule groups that are typically exposed in a file.
type RuleGroups struct {
Groups []RuleGroup `yaml:"groups"`
}
type ruleGroups struct {
Groups []yaml.Node `yaml:"groups"`
}
// Validate validates all rules in the rule groups.
func (g *RuleGroups) Validate(node ruleGroups) (errs []error) {
set := map[string]struct{}{}
for j, g := range g.Groups {
if g.Name == "" {
errs = append(errs, errors.Errorf("%d:%d: Groupname must not be empty", node.Groups[j].Line, node.Groups[j].Column))
}
if _, ok := set[g.Name]; ok {
errs = append(
errs,
errors.Errorf("%d:%d: groupname: \"%s\" is repeated in the same file", node.Groups[j].Line, node.Groups[j].Column, g.Name),
)
}
set[g.Name] = struct{}{}
for i, r := range g.Rules {
for _, node := range r.Validate() {
var ruleName yaml.Node
if r.Alert.Value != "" {
ruleName = r.Alert
} else {
ruleName = r.Record
}
errs = append(errs, &Error{
Group: g.Name,
Rule: i + 1,
RuleName: ruleName.Value,
Err: node,
})
}
}
}
return errs
}
// RuleGroup is a list of sequentially evaluated recording and alerting rules.
type RuleGroup struct {
Name string `yaml:"name"`
Interval model.Duration `yaml:"interval,omitempty"`
Rules []RuleNode `yaml:"rules"`
}
// Rule describes an alerting or recording rule.
type Rule struct {
Record string `yaml:"record,omitempty"`
Alert string `yaml:"alert,omitempty"`
Expr string `yaml:"expr"`
For model.Duration `yaml:"for,omitempty"`
Labels map[string]string `yaml:"labels,omitempty"`
Annotations map[string]string `yaml:"annotations,omitempty"`
}
// RuleNode adds yaml.v3 layer to support line and column outputs for invalid rules.
type RuleNode struct {
Record yaml.Node `yaml:"record,omitempty"`
Alert yaml.Node `yaml:"alert,omitempty"`
Expr yaml.Node `yaml:"expr"`
For model.Duration `yaml:"for,omitempty"`
Labels map[string]string `yaml:"labels,omitempty"`
Annotations map[string]string `yaml:"annotations,omitempty"`
}
// Validate the rule and return a list of encountered errors.
func (r *RuleNode) Validate() (nodes []WrappedError) {
if r.Record.Value != "" && r.Alert.Value != "" {
nodes = append(nodes, WrappedError{
err: errors.Errorf("only one of 'record' and 'alert' must be set"),
node: &r.Record,
nodeAlt: &r.Alert,
})
}
if r.Record.Value == "" && r.Alert.Value == "" {
if r.Record.Value == "0" {
nodes = append(nodes, WrappedError{
err: errors.Errorf("one of 'record' or 'alert' must be set"),
node: &r.Alert,
})
} else {
nodes = append(nodes, WrappedError{
err: errors.Errorf("one of 'record' or 'alert' must be set"),
node: &r.Record,
})
}
}
if r.Expr.Value == "" {
nodes = append(nodes, WrappedError{
err: errors.Errorf("field 'expr' must be set in rule"),
node: &r.Expr,
})
} else if _, err := parser.ParseExpr(r.Expr.Value); err != nil {
nodes = append(nodes, WrappedError{
err: errors.Wrapf(err, "could not parse expression"),
node: &r.Expr,
})
}
if r.Record.Value != "" {
if len(r.Annotations) > 0 {
nodes = append(nodes, WrappedError{
err: errors.Errorf("invalid field 'annotations' in recording rule"),
node: &r.Record,
})
}
if r.For != 0 {
nodes = append(nodes, WrappedError{
err: errors.Errorf("invalid field 'for' in recording rule"),
node: &r.Record,
})
}
if !model.IsValidMetricName(model.LabelValue(r.Record.Value)) {
nodes = append(nodes, WrappedError{
err: errors.Errorf("invalid recording rule name: %s", r.Record.Value),
node: &r.Record,
})
}
}
for k, v := range r.Labels {
if !model.LabelName(k).IsValid() || k == model.MetricNameLabel {
nodes = append(nodes, WrappedError{
err: errors.Errorf("invalid label name: %s", k),
})
}
if !model.LabelValue(v).IsValid() {
nodes = append(nodes, WrappedError{
err: errors.Errorf("invalid label value: %s", v),
})
}
}
for k := range r.Annotations {
if !model.LabelName(k).IsValid() {
nodes = append(nodes, WrappedError{
err: errors.Errorf("invalid annotation name: %s", k),
})
}
}
for _, err := range testTemplateParsing(r) {
nodes = append(nodes, WrappedError{err: err})
}
return
}
// testTemplateParsing checks if the templates used in labels and annotations
// of the alerting rules are parsed correctly.
func testTemplateParsing(rl *RuleNode) (errs []error) {
if rl.Alert.Value == "" {
// Not an alerting rule.
return errs
}
// Trying to parse templates.
tmplData := template.AlertTemplateData(map[string]string{}, map[string]string{}, 0)
defs := []string{
"{{$labels := .Labels}}",
"{{$externalLabels := .ExternalLabels}}",
"{{$value := .Value}}",
}
parseTest := func(text string) error {
tmpl := template.NewTemplateExpander(
context.TODO(),
strings.Join(append(defs, text), ""),
"__alert_"+rl.Alert.Value,
tmplData,
model.Time(timestamp.FromTime(time.Now())),
nil,
nil,
)
return tmpl.ParseTest()
}
// Parsing Labels.
for k, val := range rl.Labels {
err := parseTest(val)
if err != nil {
errs = append(errs, errors.Wrapf(err, "label %q", k))
}
}
// Parsing Annotations.
for k, val := range rl.Annotations {
err := parseTest(val)
if err != nil {
errs = append(errs, errors.Wrapf(err, "annotation %q", k))
}
}
return errs
}
// Parse parses and validates a set of rules.
func Parse(content []byte) (*RuleGroups, []error) {
var (
groups RuleGroups
node ruleGroups
errs []error
)
decoder := yaml.NewDecoder(bytes.NewReader(content))
decoder.KnownFields(true)
err := decoder.Decode(&groups)
// Ignore io.EOF which happens with empty input.
if err != nil && err != io.EOF {
errs = append(errs, err)
}
err = yaml.Unmarshal(content, &node)
if err != nil {
errs = append(errs, err)
}
if len(errs) > 0 {
return nil, errs
}
return &groups, groups.Validate(node)
}
// ParseFile reads and parses rules from a file.
func ParseFile(file string) (*RuleGroups, []error) {
b, err := ioutil.ReadFile(file)
if err != nil {
return nil, []error{errors.Wrap(err, file)}
}
rgs, errs := Parse(b)
for i := range errs {
errs[i] = errors.Wrap(errs[i], file)
}
return rgs, errs
}