Add processes exporter

[pkutishch]

Signed-off-by: Pavel Kutishchev pavel.kutishchev@olx.com

[SuperQ]

Test is failing with processes_linux_test.go:26: Cannot retrieve data from procfs getAllocatedThreads function: integer overflow on token 2573836288

[pkutishch]

Yes, i see this, trying to figure out why it fails

>> running tests
GO15VENDOREXPERIMENT=1 go test -short -race github.com/prometheus/node_exporter github.com/prometheus/node_exporter/collector
ok  	github.com/prometheus/node_exporter	(cached)
ok  	github.com/prometheus/node_exporter/collector	1.226s
>> running tests in 32-bit mode
ok  	github.com/prometheus/node_exporter	(cached)
ok  	github.com/prometheus/node_exporter/collector	0.117s
>> running end-to-end tests
./end-to-end-test.sh
root@12c9c9d715a9:/src/github.com/prometheus/node_exporter# go version
go version go1.10.2 linux/amd64

@SuperQ is that circle-ci issue? because i can see all stages build successfully on in this particular case it failed unit-tests on 32bit arch, but it there were a problem build would fail as well.

[SuperQ]

When I run the test locally, I get different values for the overflow on every run. It looks like you need to init the fixtures procPath.

Like in ipvs_linux_test.go

[SuperQ]

It looks like the path is wrong for the pid_max and threads-max fixtures files.

They need to go in collector/fixtures/proc/sys/kernel/

[pkutishch]

@SuperQ thanks, i found this out 😄 has no committed yet, my mistake, got distracted and put it to wrong place

[SuperQ]

Something is a little strange with the commits here. But the final diff looks OK. Not sure what is up with DCO not reporting.

[SuperQ]

@pkutishch, maybe if you give me access to your fork, I can poke around the git commit history?

[brian-brazil]

The 3rd commit is a merge commit, and thus lacks the DCO. I'd suggest squashing.

[SuperQ]

Ok, I squashed up the commits. Let's see if that makes the DCO bot happy.

[SuperQ]

LGTM

[SuperQ]

@brian-brazil Even after rebase, the DCO bot seems stuck on this PR. And there's no debug link for it.

[pkutishch]

@SuperQ Thanks for your help!

[SuperQ]

Ping, @discordianfish, do you have any additional comments?

[discordianfish]

LGTM, thanks!

[dswarbrick]

I realise this has already been merged, and I welcome its inclusion, but doesn't it sort of make node_procs_running and node_procs_blocked redundant?

[SuperQ]

@dswarbrick Those come from /proc/stat, which is cheap and enabled by default. This collector is expensive and disabled by default. It's a tiny bit redundant, but not overly so.