OXYGENHUB
# 67634e22f48f oxygenflow / crates / flow / src / home.rs
3.9 KiB · Rust · last changed OxygenFlow M0: pipeline parser and canonical job graph, receipts, the runner API types, flow-init, the Firecracker tier, flow check, run, rootfs import and runner 1 month ago source blame history raw
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//! `$FLOW_HOME` (default `~/.local/share/flow`): the pinned parts of each
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//! isolation tier, rootfs images by hash, scratch space and the runner's
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//! configuration, all described by `flow.toml`.
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//!
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//! ```toml
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//! [microvm]
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//! firecracker = { path = "bin/firecracker", blake3 = "…" }
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//! kernel = { path = "kernel/vmlinux", blake3 = "…" }
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//! init = { path = "bin/flow-init", blake3 = "…" }
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//!
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//! [runner]                       # only for `flow runner`
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//! hub = "https://hub.example:7343"
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//! token = "…"                    # a runner token from the hub's [flow] runner_tokens
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//! ca = "/path/to/hub-ca.pem"     # when the hub's certificate is self-signed
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//! name = "earth-1"
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//! ```
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use anyhow::{bail, Context, Result};
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use serde::Deserialize;
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use std::collections::HashMap;
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use std::path::{Path, PathBuf};
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use std::sync::Mutex;
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#[derive(Clone, Debug, Deserialize)]
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pub struct Pinned {
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    pub path: PathBuf,
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    pub blake3: String,
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}
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#[derive(Clone, Debug, Deserialize)]
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pub struct MicrovmConfig {
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    pub firecracker: Pinned,
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    pub kernel: Pinned,
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    pub init: Pinned,
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}
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#[derive(Clone, Debug, Deserialize)]
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pub struct RunnerConfig {
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    pub hub: String,
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    pub token: String,
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    pub ca: Option<PathBuf>,
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    pub name: Option<String>,
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}
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#[derive(Clone, Debug, Default, Deserialize)]
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pub struct Config {
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    pub microvm: Option<MicrovmConfig>,
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    pub runner: Option<RunnerConfig>,
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}
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pub struct Home {
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    pub root: PathBuf,
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    pub config: Config,
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    /// Files already verified, by path, with the (len, mtime) they had then.
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    verified: Mutex<HashMap<PathBuf, (u64, std::time::SystemTime)>>,
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}
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impl Home {
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    pub fn locate(explicit: Option<&Path>) -> Result<Home> {
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        let root = match explicit {
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            Some(p) => p.to_path_buf(),
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            None => match std::env::var_os("FLOW_HOME") {
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                Some(p) => PathBuf::from(p),
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                None => PathBuf::from(std::env::var_os("HOME").context("HOME is not set")?).join(".local/share/flow"),
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            },
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        };
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        let file = root.join("flow.toml");
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        let config = if file.is_file() {
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            let text = std::fs::read_to_string(&file).with_context(|| format!("read {}", file.display()))?;
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            toml::from_str(&text).with_context(|| format!("parse {}", file.display()))?
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        } else {
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            Config::default()
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        };
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        for d in ["cas", "work", "repos"] {
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            std::fs::create_dir_all(root.join(d)).with_context(|| format!("create {}", root.join(d).display()))?;
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        }
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        Ok(Home { root, config, verified: Mutex::new(HashMap::new()) })
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    }
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    pub fn resolve(&self, p: &Path) -> PathBuf {
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        if p.is_absolute() {
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            p.to_path_buf()
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        } else {
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            self.root.join(p)
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        }
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    }
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    /// Where a rootfs image with this hash lives.
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    pub fn rootfs(&self, hash: &str) -> PathBuf {
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        self.root.join("cas").join(format!("{hash}.ext4"))
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    }
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    /// A pinned file, checked against its BLAKE3 before use (again only
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    /// when its size or modification time changed since).
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    pub fn verified(&self, path: &Path, blake3_hex: &str) -> Result<PathBuf> {
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        let meta = std::fs::metadata(path).with_context(|| format!("{} is missing", path.display()))?;
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        let stamp = (meta.len(), meta.modified()?);
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        if self.verified.lock().unwrap().get(path) == Some(&stamp) {
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            return Ok(path.to_path_buf());
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        }
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        let got = hash_file(path)?;
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        if got != blake3_hex {
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            bail!("{} has BLAKE3 {got}, but {blake3_hex} is pinned", path.display());
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        }
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        self.verified.lock().unwrap().insert(path.to_path_buf(), stamp);
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        Ok(path.to_path_buf())
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    }
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}
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pub fn hash_file(path: &Path) -> Result<String> {
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    let mut h = blake3::Hasher::new();
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    h.update_reader(std::fs::File::open(path).with_context(|| format!("open {}", path.display()))?)?;
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    Ok(h.finalize().to_hex().to_string())
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}