1// Copyright 2013 The Prometheus Authors
2// Licensed under the Apache License, Version 2.0 (the "License");
3// you may not use this file except in compliance with the License.
4// You may obtain a copy of the License at
5//
6// http://www.apache.org/licenses/LICENSE-2.0
7//
8// Unless required by applicable law or agreed to in writing, software
9// distributed under the License is distributed on an "AS IS" BASIS,
10// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
11// See the License for the specific language governing permissions and
12// limitations under the License.
13
14package model
15
16import (
17	"fmt"
18	"time"
19)
20
21type AlertStatus string
22
23const (
24	AlertFiring   AlertStatus = "firing"
25	AlertResolved AlertStatus = "resolved"
26)
27
28// Alert is a generic representation of an alert in the Prometheus eco-system.
29type Alert struct {
30	// Label value pairs for purpose of aggregation, matching, and disposition
31	// dispatching. This must minimally include an "alertname" label.
32	Labels LabelSet `json:"labels"`
33
34	// Extra key/value information which does not define alert identity.
35	Annotations LabelSet `json:"annotations"`
36
37	// The known time range for this alert. Both ends are optional.
38	StartsAt     time.Time `json:"startsAt,omitempty"`
39	EndsAt       time.Time `json:"endsAt,omitempty"`
40	GeneratorURL string    `json:"generatorURL"`
41}
42
43// Name returns the name of the alert. It is equivalent to the "alertname" label.
44func (a *Alert) Name() string {
45	return string(a.Labels[AlertNameLabel])
46}
47
48// Fingerprint returns a unique hash for the alert. It is equivalent to
49// the fingerprint of the alert's label set.
50func (a *Alert) Fingerprint() Fingerprint {
51	return a.Labels.Fingerprint()
52}
53
54func (a *Alert) String() string {
55	s := fmt.Sprintf("%s[%s]", a.Name(), a.Fingerprint().String()[:7])
56	if a.Resolved() {
57		return s + "[resolved]"
58	}
59	return s + "[active]"
60}
61
62// Resolved returns true iff the activity interval ended in the past.
63func (a *Alert) Resolved() bool {
64	return a.ResolvedAt(time.Now())
65}
66
67// ResolvedAt returns true off the activity interval ended before
68// the given timestamp.
69func (a *Alert) ResolvedAt(ts time.Time) bool {
70	if a.EndsAt.IsZero() {
71		return false
72	}
73	return !a.EndsAt.After(ts)
74}
75
76// Status returns the status of the alert.
77func (a *Alert) Status() AlertStatus {
78	if a.Resolved() {
79		return AlertResolved
80	}
81	return AlertFiring
82}
83
84// Validate checks whether the alert data is inconsistent.
85func (a *Alert) Validate() error {
86	if a.StartsAt.IsZero() {
87		return fmt.Errorf("start time missing")
88	}
89	if !a.EndsAt.IsZero() && a.EndsAt.Before(a.StartsAt) {
90		return fmt.Errorf("start time must be before end time")
91	}
92	if err := a.Labels.Validate(); err != nil {
93		return fmt.Errorf("invalid label set: %s", err)
94	}
95	if len(a.Labels) == 0 {
96		return fmt.Errorf("at least one label pair required")
97	}
98	if err := a.Annotations.Validate(); err != nil {
99		return fmt.Errorf("invalid annotations: %s", err)
100	}
101	return nil
102}
103
104// Alert is a list of alerts that can be sorted in chronological order.
105type Alerts []*Alert
106
107func (as Alerts) Len() int      { return len(as) }
108func (as Alerts) Swap(i, j int) { as[i], as[j] = as[j], as[i] }
109
110func (as Alerts) Less(i, j int) bool {
111	if as[i].StartsAt.Before(as[j].StartsAt) {
112		return true
113	}
114	if as[i].EndsAt.Before(as[j].EndsAt) {
115		return true
116	}
117	return as[i].Fingerprint() < as[j].Fingerprint()
118}
119
120// HasFiring returns true iff one of the alerts is not resolved.
121func (as Alerts) HasFiring() bool {
122	for _, a := range as {
123		if !a.Resolved() {
124			return true
125		}
126	}
127	return false
128}
129
130// Status returns StatusFiring iff at least one of the alerts is firing.
131func (as Alerts) Status() AlertStatus {
132	if as.HasFiring() {
133		return AlertFiring
134	}
135	return AlertResolved
136}
137