Use shirou/gopsutil for getting CPU info on Linux

[Arthur1]

On Linux with arm64 architecture, CPU stats are not included in the host meta data sent by mackerel-agent.

This problem is caused by the different format of /proc/cpuinfo in arm64. cf.) https://blog.arthur1.dev/entry/2024/02/22/094044 (ja)

It can be solved by using shirou/gopsutil, a library that enables the acquisition of CPU information that also takes into account the arm architecture.

Test

arm64

before

$ curl -s 'https://api.mackerelio.com/api/v0/hosts/******' \
--header $MACKEREL_API_HEADER | jq '.host.meta.cpu | length'
4
$ curl -s 'https://api.mackerelio.com/api/v0/hosts/******' \
--header $MACKEREL_API_HEADER | jq '.host.meta.cpu[0]'
{}

after

$ curl -s 'https://api.mackerelio.com/api/v0/hosts/******' \
--header $MACKEREL_API_HEADER | jq '.host.meta.cpu | length'
4
$ curl -s 'https://api.mackerelio.com/api/v0/hosts/******' \
--header $MACKEREL_API_HEADER | jq '.host.meta.cpu[0]'
{
  "cache_size": "0 KB",
  "core_id": "0",
  "cores": "1",
  "family": "",
  "mhz": "1800",
  "model": "0xd08",
  "model_name": "Cortex-A72",
  "physical_id": "",
  "stepping": "3",
  "vendor_id": "ARM"
}

x86_64

There are no regressions.

before

$ curl -s 'https://api.mackerelio.com/api/v0/hosts/******' \
--header $MACKEREL_API_HEADER | jq '.host.meta.cpu | length'
2
$ curl -s 'https://api.mackerelio.com/api/v0/hosts/******' \
--header $MACKEREL_API_HEADER | jq '.host.meta.cpu[0]'
{
  "cache_size": "36608 KB",
  "core_id": "0",
  "cores": "1",
  "family": "6",
  "mhz": "2499.998",
  "model": "85",
  "model_name": "Intel(R) Xeon(R) Platinum 8259CL CPU @ 2.50GHz",
  "physical_id": "0",
  "stepping": "7",
  "vendor_id": "GenuineIntel"
}

after

$ curl -s 'https://api.mackerelio.com/api/v0/hosts/******' \
--header $MACKEREL_API_HEADER | jq '.host.meta.cpu | length'
2
$ curl -s 'https://api.mackerelio.com/api/v0/hosts/******' \
--header $MACKEREL_API_HEADER | jq '.host.meta.cpu[0]'
{
  "cache_size": "36608 KB",
  "core_id": "0",
  "cores": "1",
  "family": "6",
  "mhz": "2499.998",
  "model": "85",
  "model_name": "Intel(R) Xeon(R) Platinum 8259CL CPU @ 2.50GHz",
  "physical_id": "0",
  "stepping": "7",
  "vendor_id": "GenuineIntel"
}