mirror of
https://github.com/neondatabase/neon.git
synced 2026-01-07 05:22:56 +00:00
6c05f89f7d
1. Adds local-proxy to compute image and vm spec 2. Updates local-proxy config processing, writing PID to a file eagerly 3. Updates compute-ctl to understand local proxy compute spec and to send SIGHUP to local-proxy over that pid. closes https://github.com/neondatabase/cloud/issues/16867
57 lines
2.5 KiB
Rust
57 lines
2.5 KiB
Rust
//! Local Proxy is a feature of our BaaS Neon Authorize project.
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//!
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//! Local Proxy validates JWTs and manages the pg_session_jwt extension.
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//! It also maintains a connection pool to postgres.
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use anyhow::{Context, Result};
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use camino::Utf8Path;
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use compute_api::spec::LocalProxySpec;
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use nix::sys::signal::Signal;
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use utils::pid_file::{self, PidFileRead};
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pub fn configure(local_proxy: &LocalProxySpec) -> Result<()> {
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write_local_proxy_conf("/etc/local_proxy/config.json".as_ref(), local_proxy)?;
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notify_local_proxy("/etc/local_proxy/pid".as_ref())?;
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Ok(())
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}
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/// Create or completely rewrite configuration file specified by `path`
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fn write_local_proxy_conf(path: &Utf8Path, local_proxy: &LocalProxySpec) -> Result<()> {
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let config =
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serde_json::to_string_pretty(local_proxy).context("serializing LocalProxySpec to json")?;
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std::fs::write(path, config).with_context(|| format!("writing {path}"))?;
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Ok(())
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}
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/// Notify local proxy about a new config file.
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fn notify_local_proxy(path: &Utf8Path) -> Result<()> {
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match pid_file::read(path)? {
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// if the file doesn't exist, or isn't locked, local_proxy isn't running
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// and will naturally pick up our config later
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PidFileRead::NotExist | PidFileRead::NotHeldByAnyProcess(_) => {}
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PidFileRead::LockedByOtherProcess(pid) => {
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// From the pid_file docs:
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//
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// > 1. The other process might exit at any time, turning the given PID stale.
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// > 2. There is a small window in which `claim_for_current_process` has already
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// > locked the file but not yet updates its contents. [`read`] will return
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// > this variant here, but with the old file contents, i.e., a stale PID.
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// >
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// > The kernel is free to recycle PID once it has been `wait(2)`ed upon by
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// > its creator. Thus, acting upon a stale PID, e.g., by issuing a `kill`
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// > system call on it, bears the risk of killing an unrelated process.
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// > This is an inherent limitation of using pidfiles.
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// > The only race-free solution is to have a supervisor-process with a lifetime
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// > that exceeds that of all of its child-processes (e.g., `runit`, `supervisord`).
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//
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// This is an ok risk as we only send a SIGHUP which likely won't actually
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// kill the process, only reload config.
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nix::sys::signal::kill(pid, Signal::SIGHUP).context("sending signal to local_proxy")?;
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}
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}
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Ok(())
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}
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