Line data    Source code

       1              : //! process metrics that the [`::prometheus`] crate doesn't provide.
       2              : 
       3              : // This module has heavy inspiration from the prometheus crate's `process_collector.rs`.
       4              : 
       5              : use once_cell::sync::Lazy;
       6              : use prometheus::Gauge;
       7              : 
       8              : use crate::UIntGauge;
       9              : 
      10              : pub struct Collector {
      11              :     descs: Vec<prometheus::core::Desc>,
      12              :     vmlck: crate::UIntGauge,
      13              :     cpu_seconds_highres: Gauge,
      14              : }
      15              : 
      16              : const NMETRICS: usize = 2;
      17              : 
      18            0 : static CLK_TCK_F64: Lazy<f64> = Lazy::new(|| {
      19            0 :     let long = unsafe { libc::sysconf(libc::_SC_CLK_TCK) };
      20            0 :     if long == -1 {
      21            0 :         panic!("sysconf(_SC_CLK_TCK) failed");
      22            0 :     }
      23            0 :     let convertible_to_f64: i32 =
      24            0 :         i32::try_from(long).expect("sysconf(_SC_CLK_TCK) is larger than i32");
      25            0 :     convertible_to_f64 as f64
      26            0 : });
      27              : 
      28              : impl prometheus::core::Collector for Collector {
      29            0 :     fn desc(&self) -> Vec<&prometheus::core::Desc> {
      30            0 :         self.descs.iter().collect()
      31            0 :     }
      32              : 
      33            0 :     fn collect(&self) -> Vec<prometheus::proto::MetricFamily> {
      34            0 :         let Ok(myself) = procfs::process::Process::myself() else {
      35            0 :             return vec![];
      36              :         };
      37            0 :         let mut mfs = Vec::with_capacity(NMETRICS);
      38            0 :         if let Ok(status) = myself.status() {
      39            0 :             if let Some(vmlck) = status.vmlck {
      40            0 :                 self.vmlck.set(vmlck);
      41            0 :                 mfs.extend(self.vmlck.collect())
      42            0 :             }
      43            0 :         }
      44            0 :         if let Ok(stat) = myself.stat() {
      45            0 :             let cpu_seconds = stat.utime + stat.stime;
      46            0 :             self.cpu_seconds_highres
      47            0 :                 .set(cpu_seconds as f64 / *CLK_TCK_F64);
      48            0 :             mfs.extend(self.cpu_seconds_highres.collect());
      49            0 :         }
      50            0 :         mfs
      51            0 :     }
      52              : }
      53              : 
      54              : impl Collector {
      55            0 :     pub fn new() -> Self {
      56            0 :         let mut descs = Vec::new();
      57            0 : 
      58            0 :         let vmlck =
      59            0 :             UIntGauge::new("libmetrics_process_status_vmlck", "/proc/self/status vmlck").unwrap();
      60            0 :         descs.extend(
      61            0 :             prometheus::core::Collector::desc(&vmlck)
      62            0 :                 .into_iter()
      63            0 :                 .cloned(),
      64            0 :         );
      65            0 : 
      66            0 :         let cpu_seconds_highres = Gauge::new(
      67            0 :             "libmetrics_process_cpu_seconds_highres",
      68            0 :             "Total user and system CPU time spent in seconds.\
      69            0 :              Sub-second resolution, hence better than `process_cpu_seconds_total`.",
      70            0 :         )
      71            0 :         .unwrap();
      72            0 :         descs.extend(
      73            0 :             prometheus::core::Collector::desc(&cpu_seconds_highres)
      74            0 :                 .into_iter()
      75            0 :                 .cloned(),
      76            0 :         );
      77            0 : 
      78            0 :         Self {
      79            0 :             descs,
      80            0 :             vmlck,
      81            0 :             cpu_seconds_highres,
      82            0 :         }
      83            0 :     }
      84              : }
      85              : 
      86              : impl Default for Collector {
      87            0 :     fn default() -> Self {
      88            0 :         Self::new()
      89            0 :     }
      90              : }