systemd service cannot start

[panboo0106]

Describe the issue:
systemd service cannot start

Describe the expected behavior:

# journalctl -u postgres_exporter@pg12.service
/etc/systemd/system/postgres_exporter@.service:8: Ignoring unknown escape sequences: "set -o pipefail; cat $QUERY_FILE_LIST | sed -e 's/#PG_STAT_ST...

I think double '$$' not good for me:

i can work when i use one '$'

Tell us about your environment:

• pgMonitor version: current version
• Container or non-container: no
• Container name / image: no
• Operating System for non-container: Rocky Linux8.5
• PostgreSQL Version: 12.11
• Exporter(s) in use (incl. version): 0.11.1
• Prometheus version: no
• AlertManager version: no
• Grafana version: no

[keithf4]

What version of pgMonitor are you using? We'd seen this error in the past as well when trying to use startup options containing multiple .yml files and it was fixed with this PR in version 4.6

#269

[panboo0106]

What version of pgMonitor are you using? We'd seen this error in the past as well when trying to use startup options containing multiple .yml files and it was fixed with this PR in version 4.6

#269
v4.7

[keithf4]

Can you please share the entire contents of your service startup file? Just to make sure if the changes were applied and so we can test with what you have?

[keithf4]

Also noticed that your service file is named differently than the one pgMonitor provides. How are you installing it?

[panboo0106]

PGBACKREST_INFO_THROTTLE_MINUTES=10
PG_STAT_STATEMENTS_LIMIT=20
PG_STAT_STATEMENTS_THROTTLE_MINUTES=-1
OPT="--web.listen-address=0.0.0.0:9187 --extend.query-path=/etc/xdrops/postgres_exporter/12/queries.yml --disable-default-metrics --disable-settings-metrics"
DATA_SOURCE_NAME="postgresql://ccp_monitoring:xxxxxxxxxxx@localhost:5432/postgres?sslmode=disable"
# For global / cluster metric
QUERY_FILE_LIST="/etc/xdrops/postgres_exporter/12/queries_global.yml /etc/xdrops/postgres_exporter/12/queries_general.yml /etc/xdrops/postgres_exporter/12/queries_backrest.yml /etc/xdrops/postgres_exporter/12/queries_pgbouncer.yml"

[Unit]
Description=Postgres Exporter Server - Service Instance: %I
After=network-online.target
[Service]
User=ccp_monitoring
WorkingDirectory=/etc/xdrops/postgres_exporter
EnvironmentFile=/etc/xdrops/postgres_exporter/12/systemd/%i
ExecStartPre=/bin/bash -c "set -o pipefail; cat $QUERY_FILE_LIST | sed -e 's/#PG_STAT_STATEMENTS_THROTTLE_MINUTES#/${PG_STAT_STATEMENTS_THROTTLE_MINUTES}/g' -e 's/#PGBACKREST_INFO_THROTTLE_MINUTES#/${PGBACKREST_INFO_THROTTLE_MINUTES}/g' -e 's/#PG_STAT_STATEMENTS_LIMIT#/${PG_STAT_STATEMENTS_LIMIT}/g' > $(echo $OPT | sed 's/.*--extend.query-path=\([^\ ]*\.yml\).*/\1/')"
ExecStart=/etc/xdrops/postgres_exporter/postgres_exporter $OPT
ExecReload=/usr/bin/kill -HUP $MAINPID
Restart=always
[Install]
WantedBy=multi-user.target

pgbouncer backrest metrics show on grafana well

I just only change filename 、directory path and discard a ‘$`.

[keithf4]

Thank you for the info. We'll look into it.

[hunleyd]

So I do see the $$ in the file in my testing, but the service still starts in my testing on Rocky 8. I edited the service file to make it a single $ and rebooted the node with no issues. I think we need to make the edit @keithf4

[keithf4]

@leo-minorui

So I've included this change in the PR for the PG15 update. It seems like it may have been trying to escape the user of a dollar here according to systemd rules, but may not be needed in this case?
https://www.freedesktop.org/software/systemd/man/systemd.service.html

To pass a literal dollar sign, use "$$"

However, I'm still a bit curious how this is breaking for you if we cannot reproduce this on our Rocky test system, nor any other OS's that we test (RHEL8/7, CenOS7, Ubuntu20/22). Do you have anything else customized with the shell for the user that's running the exporter? Or done anything to the bash interpreter since this is explicitly calling bash?

[keithf4]

What version of systemd are you running? This was from a CentOS7 system I have running now

systemctl --version
systemd 219

[panboo0106]

@leo-minorui

So I've included this change in the PR for the PG15 update. It seems like it may have been trying to escape the user of a dollar here according to systemd rules, but may not be needed in this case? https://www.freedesktop.org/software/systemd/man/systemd.service.html

To pass a literal dollar sign, use "$$"

However, I'm still a bit curious how this is breaking for you if we cannot reproduce this on our Rocky test system, nor any other OS's that we test (RHEL8/7, CenOS7, Ubuntu20/22). Do you have anything else customized with the shell for the user that's running the exporter? Or done anything to the bash interpreter since this is explicitly calling bash?

Sorry to reply late.
The version is systemd 239 (239-58.el8)

For me, the logic of command( > $(echo $OPT | sed 's/.--extend.query-path=([^\ ].yml).*/\1/')") is to combine multiple file contents into a new file named 'queries.yaml'

and in my mind , double dollar signs mean process number in bash.
like this :

echo $$ 
854301