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types: fix alert merging #1611

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Merged
mxinden merged 1 commit into from
Nov 9, 2018
Merged

types: fix alert merging #1611

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19 changes: 12 additions & 7 deletions types/types.go
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Original file line number Diff line number Diff line change
Expand Up @@ -295,9 +295,8 @@ func Alerts(alerts ...*Alert) model.Alerts {
res := make(model.Alerts, 0, len(alerts))
for _, a := range alerts {
v := a.Alert
// If the end timestamp was set as the expected value in case
// of a timeout but is not reached yet, do not expose it.
if a.Timeout && !a.Resolved() {
// If the end timestamp is not reached yet, do not expose it.
if !a.Resolved() {
v.EndsAt = time.Time{}
}
res = append(res, &v)
Expand All @@ -321,10 +320,16 @@ func (a *Alert) Merge(o *Alert) *Alert {
res.StartsAt = a.StartsAt
}

// A non-timeout resolved timestamp always rules.
// The latest explicit resolved timestamp wins.
if a.EndsAt.After(o.EndsAt) && !a.Timeout {
res.EndsAt = a.EndsAt
if o.Resolved() {
// The latest explicit resolved timestamp wins if both alerts are effectively resolved.
if a.Resolved() && a.EndsAt.After(o.EndsAt) {
res.EndsAt = a.EndsAt
}
} else {
// A non-timeout timestamp always rules if it is the latest.
if a.EndsAt.After(o.EndsAt) && !a.Timeout {
res.EndsAt = a.EndsAt
}
}

return &res
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206 changes: 201 additions & 5 deletions types/types_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -16,6 +16,7 @@ package types
import (
"reflect"
"sort"
"strconv"
"testing"
"time"

Expand All @@ -26,13 +27,17 @@ import (
func TestAlertMerge(t *testing.T) {
now := time.Now()

// By convention, alert A is always older than alert B.
pairs := []struct {
A, B, Res *Alert
}{
{
// Both alerts have the Timeout flag set.
// StartsAt is defined by Alert A.
// EndsAt is defined by Alert B.
A: &Alert{
Alert: model.Alert{
StartsAt: now.Add(-time.Minute),
StartsAt: now.Add(-2 * time.Minute),
EndsAt: now.Add(2 * time.Minute),
},
UpdatedAt: now,
Expand All @@ -46,6 +51,61 @@ func TestAlertMerge(t *testing.T) {
UpdatedAt: now.Add(time.Minute),
Timeout: true,
},
Res: &Alert{
Alert: model.Alert{
StartsAt: now.Add(-2 * time.Minute),
EndsAt: now.Add(3 * time.Minute),
},
UpdatedAt: now.Add(time.Minute),
Timeout: true,
},
},
{
// Alert A has the Timeout flag set while Alert B has it unset.
// StartsAt is defined by Alert A.
// EndsAt is defined by Alert B.
A: &Alert{
Alert: model.Alert{
StartsAt: now.Add(-time.Minute),
EndsAt: now.Add(3 * time.Minute),
},
UpdatedAt: now,
Timeout: true,
},
B: &Alert{
Alert: model.Alert{
StartsAt: now,
EndsAt: now.Add(2 * time.Minute),
},
UpdatedAt: now.Add(time.Minute),
},
Res: &Alert{
Alert: model.Alert{
StartsAt: now.Add(-time.Minute),
EndsAt: now.Add(2 * time.Minute),
},
UpdatedAt: now.Add(time.Minute),
},
},
{
// Alert A has the Timeout flag unset while Alert B has it set.
// StartsAt is defined by Alert A.
// EndsAt is defined by Alert A.
A: &Alert{
Alert: model.Alert{
StartsAt: now.Add(-time.Minute),
EndsAt: now.Add(3 * time.Minute),
},
UpdatedAt: now,
},
B: &Alert{
Alert: model.Alert{
StartsAt: now,
EndsAt: now.Add(2 * time.Minute),
},
UpdatedAt: now.Add(time.Minute),
Timeout: true,
},
Res: &Alert{
Alert: model.Alert{
StartsAt: now.Add(-time.Minute),
Expand All @@ -55,12 +115,148 @@ func TestAlertMerge(t *testing.T) {
Timeout: true,
},
},
{
// Both alerts have the Timeout flag unset and are not resolved.
// StartsAt is defined by Alert A.
// EndsAt is defined by Alert A.
A: &Alert{
Alert: model.Alert{
StartsAt: now.Add(-time.Minute),
EndsAt: now.Add(3 * time.Minute),
},
UpdatedAt: now,
},
B: &Alert{
Alert: model.Alert{
StartsAt: now,
EndsAt: now.Add(2 * time.Minute),
},
UpdatedAt: now.Add(time.Minute),
},
Res: &Alert{
Alert: model.Alert{
StartsAt: now.Add(-time.Minute),
EndsAt: now.Add(3 * time.Minute),
},
UpdatedAt: now.Add(time.Minute),
},
},
{
// Both alerts have the Timeout flag unset and are not resolved.
// StartsAt is defined by Alert A.
// EndsAt is defined by Alert B.
A: &Alert{
Alert: model.Alert{
StartsAt: now.Add(-time.Minute),
EndsAt: now.Add(3 * time.Minute),
},
UpdatedAt: now,
},
B: &Alert{
Alert: model.Alert{
StartsAt: now.Add(-time.Minute),
EndsAt: now.Add(4 * time.Minute),
},
UpdatedAt: now.Add(time.Minute),
},
Res: &Alert{
Alert: model.Alert{
StartsAt: now.Add(-time.Minute),
EndsAt: now.Add(4 * time.Minute),
},
UpdatedAt: now.Add(time.Minute),
},
},
{
// Both alerts have the Timeout flag unset, A is resolved while B isn't.
// StartsAt is defined by Alert A.
// EndsAt is defined by Alert B.
A: &Alert{
Alert: model.Alert{
StartsAt: now.Add(-3 * time.Minute),
EndsAt: now.Add(-time.Minute),
},
UpdatedAt: now,
},
B: &Alert{
Alert: model.Alert{
StartsAt: now.Add(-2 * time.Minute),
EndsAt: now.Add(time.Minute),
},
UpdatedAt: now.Add(time.Minute),
},
Res: &Alert{
Alert: model.Alert{
StartsAt: now.Add(-3 * time.Minute),
EndsAt: now.Add(time.Minute),
},
UpdatedAt: now.Add(time.Minute),
},
},
{
// Both alerts have the Timeout flag unset, B is resolved while A isn't.
// StartsAt is defined by Alert A.
// EndsAt is defined by Alert B.
A: &Alert{
Alert: model.Alert{
StartsAt: now.Add(-2 * time.Minute),
EndsAt: now.Add(3 * time.Minute),
},
UpdatedAt: now,
},
B: &Alert{
Alert: model.Alert{
StartsAt: now.Add(-2 * time.Minute),
EndsAt: now,
},
UpdatedAt: now.Add(time.Minute),
},
Res: &Alert{
Alert: model.Alert{
StartsAt: now.Add(-2 * time.Minute),
EndsAt: now,
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@mxinden mxinden Nov 8, 2018

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I am confused by this. If I have two alerts, where one is firing and one is not, I expect the merged alert to still be firing, right? Especially as none of them have the Timeout flag set.

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@stuartnelson3 stuartnelson3 Nov 9, 2018

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Because B is received after A, it's EndsAt value "wins" because A isn't resolved (is what I'm reading from the code and comments).

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@simonpasquier simonpasquier Nov 9, 2018

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Because B is received after A

Exactly, an alert that is effectively resolved wins over an older alert that was firing previously.

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@mxinden mxinden Nov 9, 2018

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Right got it. Thanks for clarifying @stuartnelson3 & @simonpasquier!

},
UpdatedAt: now.Add(time.Minute),
},
},
{
// Both alerts are resolved (EndsAt < now).
// StartsAt is defined by Alert B.
// EndsAt is defined by Alert A.
A: &Alert{
Alert: model.Alert{
StartsAt: now.Add(-3 * time.Minute),
EndsAt: now.Add(-time.Minute),
},
UpdatedAt: now.Add(-time.Minute),
},
B: &Alert{
Alert: model.Alert{
StartsAt: now.Add(-4 * time.Minute),
EndsAt: now.Add(-2 * time.Minute),
},
UpdatedAt: now.Add(time.Minute),
},
Res: &Alert{
Alert: model.Alert{
StartsAt: now.Add(-4 * time.Minute),
EndsAt: now.Add(-1 * time.Minute),
},
UpdatedAt: now.Add(time.Minute),
},
},
}

for _, p := range pairs {
if res := p.A.Merge(p.B); !reflect.DeepEqual(p.Res, res) {
t.Errorf("unexpected merged alert %#v", res)
}
for i, p := range pairs {
p := p
t.Run(strconv.Itoa(i), func(t *testing.T) {
if res := p.A.Merge(p.B); !reflect.DeepEqual(p.Res, res) {
t.Errorf("unexpected merged alert %#v", res)
}
if res := p.B.Merge(p.A); !reflect.DeepEqual(p.Res, res) {
t.Errorf("unexpected merged alert %#v", res)
}
})
}
}

Expand Down