Fix pid_count with systemd_unit in procstat_lookup

[Frakenz]

Attempt at fixing #5300. Not sure if using an OR statement or writing a separate if was a better practice. Since both check for valid PIDs I used an OR statement.
Also I tested this on golang and know almost nothing of GO, so there might be better ways to write this.

Required for all PRs:

• Signed CLA.
• Associated README.md updated.
• Has appropriate unit tests.

[Frakenz]

Is there a chance this failed because I made the edit directly on github's website?
What am I doing wrong?

It could be a syntax error that worked on versions 1.9 and 1.10 but not from 1.11 onwards. I will give it another Go on a few days if I have enough time to install and learn the language a bit.

plugins/inputs/procstat/procstat.go
Run make fmt to fix them.
make: *** [fmtcheck] Error 1
Command exited with code 2

[danielnelson]

I think you just need a space before the {:

- if len(kv[1]) == 0 || bytes.Equal(kv[1], []byte("0")){
+ if len(kv[1]) == 0 || bytes.Equal(kv[1], []byte("0")) {

[xczdenis]

It seems to me that it doesn't work as expected. When I use influx db as output client, it works fine. However, I also use prometheus_client:

[[outputs.prometheus_client]]
    listen = ":9193"
    path = "/metrics"
    expiration_interval = "0s"

I want to control the status of nexus.service. When the nexus is running, I get a response on url my-server-ip:9193/metrics like this:

# HELP systemd_units_active_code Telegraf collected metric
# TYPE systemd_units_active_code untyped
systemd_units_active_code{active="active",load="loaded",name="nexus.service",sub="running"} 0

But if I shut down the service, I get this:

# HELP systemd_units_active_code Telegraf collected metric
# TYPE systemd_units_active_code untyped
systemd_units_active_code{active="active",load="loaded",name="nexus.service",sub="running"} 0
systemd_units_active_code{active="inactive",load="loaded",name="nexus.service",sub="dead"} 2

So when I use this query: systemd_units_active_code{name="nexus.service"} I get 2 rows every time period - active and inactive. Therefore, I can't define the correct current state. Maybe i'm doing smth wrong.