view rust/rhg/src/blackbox.rs @ 47610:f89d3050dcd5

resolve: use the `parentchange` context manager to apply merge action

In an ideal world, we would not have to do that. However, we are miles away from
being ready to not have to do it.

So we add this context manager alongside a long comment. This will help use to
get to the point were have two distinct API with strict rules about when to call
them.

Differential Revision: https://phab.mercurial-scm.org/D11074

//! Logging for repository events, including commands run in the repository.

use crate::CliInvocation;
use format_bytes::format_bytes;
use hg::errors::HgError;
use hg::repo::Repo;
use hg::utils::{files::get_bytes_from_os_str, shell_quote};

const ONE_MEBIBYTE: u64 = 1 << 20;

// TODO: somehow keep defaults in sync with `configitem` in `hgext/blackbox.py`
const DEFAULT_MAX_SIZE: u64 = ONE_MEBIBYTE;
const DEFAULT_MAX_FILES: u32 = 7;

// Python does not support %.3f, only %f
const DEFAULT_DATE_FORMAT: &str = "%Y/%m/%d %H:%M:%S%.3f";

type DateTime = chrono::DateTime<chrono::Local>;

pub struct ProcessStartTime {
    /// For measuring duration
    monotonic_clock: std::time::Instant,
    /// For formatting with year, month, day, etc.
    calendar_based: DateTime,
}

impl ProcessStartTime {
    pub fn now() -> Self {
        Self {
            monotonic_clock: std::time::Instant::now(),
            calendar_based: chrono::Local::now(),
        }
    }
}

pub struct Blackbox<'a> {
    process_start_time: &'a ProcessStartTime,
    /// Do nothing if this is `None`
    configured: Option<ConfiguredBlackbox<'a>>,
}

struct ConfiguredBlackbox<'a> {
    repo: &'a Repo,
    max_size: u64,
    max_files: u32,
    date_format: &'a str,
}

impl<'a> Blackbox<'a> {
    pub fn new(
        invocation: &'a CliInvocation<'a>,
        process_start_time: &'a ProcessStartTime,
    ) -> Result<Self, HgError> {
        let configured = if let Ok(repo) = invocation.repo {
            if invocation.config.get(b"extensions", b"blackbox").is_none() {
                // The extension is not enabled
                None
            } else {
                Some(ConfiguredBlackbox {
                    repo,
                    max_size: invocation
                        .config
                        .get_byte_size(b"blackbox", b"maxsize")?
                        .unwrap_or(DEFAULT_MAX_SIZE),
                    max_files: invocation
                        .config
                        .get_u32(b"blackbox", b"maxfiles")?
                        .unwrap_or(DEFAULT_MAX_FILES),
                    date_format: invocation
                        .config
                        .get_str(b"blackbox", b"date-format")?
                        .unwrap_or(DEFAULT_DATE_FORMAT),
                })
            }
        } else {
            // Without a local repository there’s no `.hg/blackbox.log` to
            // write to.
            None
        };
        Ok(Self {
            process_start_time,
            configured,
        })
    }

    pub fn log_command_start(&self) {
        if let Some(configured) = &self.configured {
            let message = format_bytes!(b"(rust) {}", format_cli_args());
            configured.log(&self.process_start_time.calendar_based, &message);
        }
    }

    pub fn log_command_end(&self, exit_code: i32) {
        if let Some(configured) = &self.configured {
            let now = chrono::Local::now();
            let duration = self
                .process_start_time
                .monotonic_clock
                .elapsed()
                .as_secs_f64();
            let message = format_bytes!(
                b"(rust) {} exited {} after {} seconds",
                format_cli_args(),
                exit_code,
                format_bytes::Utf8(format_args!("{:.03}", duration))
            );
            configured.log(&now, &message);
        }
    }
}

impl ConfiguredBlackbox<'_> {
    fn log(&self, date_time: &DateTime, message: &[u8]) {
        let date = format_bytes::Utf8(date_time.format(self.date_format));
        let user = users::get_current_username().map(get_bytes_from_os_str);
        let user = user.as_deref().unwrap_or(b"???");
        let rev = format_bytes::Utf8(match self.repo.dirstate_parents() {
            Ok(parents) if parents.p2 == hg::revlog::node::NULL_NODE => {
                format!("{:x}", parents.p1)
            }
            Ok(parents) => format!("{:x}+{:x}", parents.p1, parents.p2),
            Err(_dirstate_corruption_error) => {
                // TODO: log a non-fatal warning to stderr
                "???".to_owned()
            }
        });
        let pid = std::process::id();
        let line = format_bytes!(
            b"{} {} @{} ({})> {}\n",
            date,
            user,
            rev,
            pid,
            message
        );
        let result =
            hg::logging::LogFile::new(self.repo.hg_vfs(), "blackbox.log")
                .max_size(Some(self.max_size))
                .max_files(self.max_files)
                .write(&line);
        match result {
            Ok(()) => {}
            Err(_io_error) => {
                // TODO: log a non-fatal warning to stderr
            }
        }
    }
}

fn format_cli_args() -> Vec<u8> {
    let mut args = std::env::args_os();
    let _ = args.next(); // Skip the first (or zeroth) arg, the name of the `rhg` executable
    let mut args = args.map(|arg| shell_quote(&get_bytes_from_os_str(arg)));
    let mut formatted = Vec::new();
    if let Some(arg) = args.next() {
        formatted.extend(arg)
    }
    for arg in args {
        formatted.push(b' ');
        formatted.extend(arg)
    }
    formatted
}