when using fluent-plugin-mongo, threads didnot exit and sockets to mongo didnot close

[seamaner]

the container uses many socket fds and threads, it may be a leak.
0x01
now it has 4k+ threads:
ls /proc/10/task | wc
4384 4384 21044
0x02

ps -elf | grep ruby

0 S root 9712 6033 0 80 0 - 3875 pipe_w 17:45 pts/2 00:00:00 grep --color=auto ruby
4 S 999 11386 11358 0 80 0 - 27546 poll_s 16:13 ? 00:00:04 /usr/local/bin/ruby /usr/local/bundle/bin/fluentd -c /fluentd/etc/fluent.conf

use lsof can get that process has many tcp connections to mongo:
4 S 999 11996 11386 5 80 0 - 3527387 poll_s 16:13 ? 00:04:54 /usr/local/bin/ruby -Eascii-8bit:ascii-8bit /usr/local/bundle/bin/fluentd -c /fluentd/etc/fluent.conf --under-supervisor
ruby 11996 999 4461u IPv4 145632322 0t0 TCP localhost:35948->localhost:27017 (ESTABLISHED)
lsof: no pwd entry for UID 999
ruby 11996 999 4462u IPv4 145630540 0t0 TCP localhost:35976->localhost:27017 (ESTABLISHED)
lsof: no pwd entry for UID 999
ruby 11996 999 4463u IPv4 145629667 0t0 TCP localhost:35978->localhost:27017 (ESTABLISHED)
lsof: no pwd entry for UID 999
ruby 11996 999 4464u IPv4 145629694 0t0 TCP localhost:35994->localhost:27017 (ESTABLISHED)
lsof: no pwd entry for UID 999
ruby 11996 999 4465u IPv4 145629695 0t0 TCP localhost:35996->localhost:27017 (ESTABLISHED)
lsof: no pwd entry for UID 999
ruby 11996 999 4466u IPv4 145630677 0t0 TCP localhost:36030->localhost:27017 (ESTABLISHED)
lsof: no pwd entry for UID 999
ruby 11996 999 4467u IPv4 145630681 0t0 TCP localhost:36032->localhost:27017 (ESTABLISHED)
lsof: no pwd entry for UID 999
ruby 11996 999 4468u IPv4 145629743 0t0 TCP localhost:36040->localhost:27017 (ESTABLISHED)
lsof: no pwd entry for UID 999
ruby 11996 999 4469u IPv4 145629744 0t0 TCP localhost:36042->localhost:27017 (ESTABLISHED)
lsof: no pwd entry for UID 999
ruby 11996 999 4470u IPv4 145631716 0t0 TCP localhost:36094->localhost:27017 (ESTABLISHED)
lsof: no pwd entry for UID 999
ruby 11996 999 4471u IPv4 145631717 0t0 TCP localhost:36096->localhost:27017 (ESTABLISHED)
lsof: no pwd entry for UID 999
ruby 11996 999 4472u IPv4 145630872 0t0 TCP localhost:36100->localhost:27017 (ESTABLISHED)
lsof: no pwd entry for UID 999
ruby 11996 999 4473u IPv4 145630876 0t0 TCP localhost:36102->localhost:27017 (ESTABLISHED)

it seems that when a message comes to Port 24224, fluentd creates a thread and a mongo connection, but when the connection to 24224 closed, the thread did not close and the connection to mongo leaked.

any suggestions ?

[seamaner]

fluent.conf:
fluent.conf.txt
`

[seamaner]

Dockfile used:

Dockerfile.txt

[cosmo0920]

fluentd-dcoker-image does not provide mongo plugin image. This is user-custom image issue.
So, I transferred this issue from fluentd-docker-image.