Systemd service results in empty "exe" prometheus label

[ancoron]

Bug description

When running using the provided (in packaging/linux/ubuntu) systemd service, the sandbox established by SystemD effectively prevents scaphandre from determining the "exe" label value (I suspect from /proc/<pid>/exe).

Running with root (without sandboxing) provides a value for the exe label for many processes.

To Reproduce

• start the systemd service

Expected behavior

The exe label has a value for most processes.

Screenshots

Expected example:

curl -s 'http://localhost:8080/metrics' | grep -F 'scaph_process_memory_bytes' | sed -E '/exe=""/d' | wc -l
169

Actual example:

curl -s 'http://localhost:8080/metrics' | grep -F 'scaph_process_memory_bytes' | sed -E '/exe=""/d' | wc -l
3

...which essentially is something like this:

# HELP scaph_process_memory_bytes Physical RAM usage by the process, in bytes
# TYPE scaph_process_memory_bytes gauge
scaph_process_memory_bytes{pid="957",exe="/usr/local/bin/scaphandre",cmdline="/usr/bin/scaphandreprometheus--containers--port=8080"} 30650368

...so it only is able to determine the exe for itself, no other processes.

Environment

Arch Linux using Kernel 6.7.6-arch1-1