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Fix panic: don't send events if client is nil #15568

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Merged
mtojek merged 6 commits into from
Jan 20, 2020
Merged

Fix panic: don't send events if client is nil #15568

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2547b26
Fix panic: don't send events if client is nil
Jan 15, 2020
128f4a3
Use mutex
Jan 16, 2020
e0acdc5
Add CHANGELOG entry
Jan 16, 2020
57d62c2
Rename changelog entry
Jan 16, 2020
a297c68
Fix: changelog
Jan 17, 2020
bce69b8
Temporarily use specific logstash release
Jan 20, 2020
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1 change: 1 addition & 0 deletions CHANGELOG.next.asciidoc
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Original file line number Diff line number Diff line change
Expand Up @@ -39,6 +39,7 @@ https://github.com/elastic/beats/compare/v7.0.0-alpha2...master[Check the HEAD d
*Affecting all Beats*

TLS or Beats that accept connections over TLS and validate client certificates. {pull}14146[14146]
- Fix panic in the Logstash output when trying to send events to closed connection. {pull}15568[15568]

*Auditbeat*

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21 changes: 20 additions & 1 deletion libbeat/outputs/logstash/async.go
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Expand Up @@ -18,7 +18,9 @@
package logstash

import (
"errors"
"net"
"sync"
"time"

"github.com/elastic/beats/libbeat/beat"
Expand All @@ -37,6 +39,8 @@ type asyncClient struct {
win *window

connect func() error

mutex sync.Mutex
}

type msgRef struct {
Expand Down Expand Up @@ -113,7 +117,11 @@ func (c *asyncClient) Connect() error {
}

func (c *asyncClient) Close() error {
c.mutex.Lock()
defer c.mutex.Unlock()

logp.Debug("logstash", "close connection")

if c.client != nil {
err := c.client.Close()
c.client = nil
Expand Down Expand Up @@ -197,12 +205,23 @@ func (c *asyncClient) publishWindowed(
}

func (c *asyncClient) sendEvents(ref *msgRef, events []publisher.Event) error {
client := c.getClient()
if client == nil {
return errors.New("connection closed")
}
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@urso urso Jan 15, 2020

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The Close method can be called from another thread. Better use an atomic pointer or mutex to load c.client into a local variable. The v2.AsyncClient should be thread safe (just uses net.Conn.Close() to close the underlying connection/FD).

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@mtojek mtojek Jan 16, 2020

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Fixed.

window := make([]interface{}, len(events))
for i := range events {
window[i] = &events[i].Content
}
ref.count.Inc()
return c.client.Send(ref.callback, window)
return client.Send(ref.callback, window)
}

func (c *asyncClient) getClient() *v2.AsyncClient {
c.mutex.Lock()
client := c.client
c.mutex.Unlock()
return client
}

func (r *msgRef) callback(seq uint32, err error) {
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2 changes: 1 addition & 1 deletion testing/environments/snapshot.yml
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Expand Up @@ -17,7 +17,7 @@ services:
- "indices.id_field_data.enabled=true"

logstash:
image: docker.elastic.co/logstash/logstash:8.0.0-SNAPSHOT
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@urso urso Jan 20, 2020

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The image is normally maintained by RE. @mikemadden42 please create a follow up PR restoring 8.0.0-SNAPSHOT. We can retrigger CI every now and then.

image: docker.elastic.co/logstash/logstash@sha256:e01cf165142edf8d67485115b938c94deeda66153e9516aa2ce69ee417c5fc33
healthcheck:
test: ["CMD", "curl", "-f", "http://localhost:9600/_node/stats"]
retries: 600
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