prometheus/pkg/rulefmt/rulefmt.go
Ganesh Vernekar 05726c5ea2 Test template expansion while loading groups (#4537)
Signed-off-by: Ganesh Vernekar <cs15btech11018@iith.ac.in>
2018-09-13 13:55:58 +01:00

209 lines
5.5 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 (
"context"
"fmt"
"io/ioutil"
"time"
"github.com/pkg/errors"
"github.com/prometheus/common/model"
"github.com/prometheus/prometheus/pkg/timestamp"
"github.com/prometheus/prometheus/promql"
"github.com/prometheus/prometheus/template"
yaml "gopkg.in/yaml.v2"
)
// Error represents semantical errors on parsing rule groups.
type Error struct {
Group string
Rule int
RuleName string
Err error
}
func (err *Error) Error() string {
return errors.Wrapf(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"`
}
// Validate validates all rules in the rule groups.
func (g *RuleGroups) Validate() (errs []error) {
set := map[string]struct{}{}
for _, g := range g.Groups {
if g.Name == "" {
errs = append(errs, errors.Errorf("Groupname should not be empty"))
}
if _, ok := set[g.Name]; ok {
errs = append(
errs,
errors.Errorf("groupname: \"%s\" is repeated in the same file", g.Name),
)
}
set[g.Name] = struct{}{}
for i, r := range g.Rules {
for _, err := range r.Validate() {
var ruleName string
if r.Alert != "" {
ruleName = r.Alert
} else {
ruleName = r.Record
}
errs = append(errs, &Error{
Group: g.Name,
Rule: i,
RuleName: ruleName,
Err: err,
})
}
}
}
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 []Rule `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"`
}
// Validate the rule and return a list of encountered errors.
func (r *Rule) Validate() (errs []error) {
if r.Record != "" && r.Alert != "" {
errs = append(errs, errors.Errorf("only one of 'record' and 'alert' must be set"))
}
if r.Record == "" && r.Alert == "" {
errs = append(errs, errors.Errorf("one of 'record' or 'alert' must be set"))
}
if r.Expr == "" {
errs = append(errs, errors.Errorf("field 'expr' must be set in rule"))
} else if _, err := promql.ParseExpr(r.Expr); err != nil {
errs = append(errs, errors.Errorf("could not parse expression: %s", err))
}
if r.Record != "" {
if len(r.Annotations) > 0 {
errs = append(errs, errors.Errorf("invalid field 'annotations' in recording rule"))
}
if r.For != 0 {
errs = append(errs, errors.Errorf("invalid field 'for' in recording rule"))
}
if !model.IsValidMetricName(model.LabelValue(r.Record)) {
errs = append(errs, errors.Errorf("invalid recording rule name: %s", r.Record))
}
}
for k, v := range r.Labels {
if !model.LabelName(k).IsValid() {
errs = append(errs, errors.Errorf("invalid label name: %s", k))
}
if !model.LabelValue(v).IsValid() {
errs = append(errs, errors.Errorf("invalid label value: %s", v))
}
}
for k := range r.Annotations {
if !model.LabelName(k).IsValid() {
errs = append(errs, errors.Errorf("invalid annotation name: %s", k))
}
}
errs = append(errs, testTemplateParsing(r)...)
return errs
}
// testTemplateParsing checks if the templates used in labels and annotations
// of the alerting rules are parsed correctly.
func testTemplateParsing(rl *Rule) (errs []error) {
if rl.Alert == "" {
// Not an alerting rule.
return errs
}
// Trying to parse templates.
tmplData := template.AlertTemplateData(make(map[string]string), 0)
defs := "{{$labels := .Labels}}{{$value := .Value}}"
parseTest := func(text string) error {
tmpl := template.NewTemplateExpander(
context.TODO(),
defs+text,
"__alert_"+rl.Alert,
tmplData,
model.Time(timestamp.FromTime(time.Now())),
nil,
nil,
)
return tmpl.ParseTest()
}
// Parsing Labels.
for _, val := range rl.Labels {
err := parseTest(val)
if err != nil {
errs = append(errs, fmt.Errorf("msg=%s", err.Error()))
}
}
// Parsing Annotations.
for _, val := range rl.Annotations {
err := parseTest(val)
if err != nil {
errs = append(errs, fmt.Errorf("msg=%s", err.Error()))
}
}
return errs
}
// Parse parses and validates a set of rules.
func Parse(content []byte) (*RuleGroups, []error) {
var groups RuleGroups
if err := yaml.UnmarshalStrict(content, &groups); err != nil {
return nil, []error{err}
}
return &groups, groups.Validate()
}
// 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{err}
}
return Parse(b)
}