forked from wrenn/wrenn
feat: rewrite envd guest agent in Rust (envd-rs)
Complete Rust rewrite of the Go envd guest daemon that runs as PID 1 inside Firecracker microVMs. Feature-complete across all 8 phases: - Health, metrics, and env var endpoints - Crypto (SHA-256/512, HMAC), auth (secure token, signing), init/snapshot - Connect RPC via connectrpc + buffa (process + filesystem services) - File transfer (GET/POST /files) with gzip, multipart, chown, ENOSPC - Port subsystem (/proc/net/tcp scanner, socat forwarder) - Cgroup2 manager with noop fallback - Snapshot/restore lifecycle (conntracker, port subsystem stop/restart) - SIGTERM graceful shutdown, --cmd initial process spawn - MMDS metadata polling for Firecracker mode 42 source files, ~4200 LOC, 4.1MB stripped release binary. Makefile updated: build-envd now targets Rust (musl static), build-envd-go preserved for Go builds.
This commit is contained in:
274
envd-rs/src/http/init.rs
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274
envd-rs/src/http/init.rs
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@ -0,0 +1,274 @@
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use std::collections::HashMap;
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use std::sync::Arc;
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use std::sync::atomic::Ordering;
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use axum::Json;
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use axum::extract::State;
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use axum::http::{StatusCode, header};
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use axum::response::IntoResponse;
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use serde::Deserialize;
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use crate::crypto;
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use crate::host::mmds;
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use crate::state::AppState;
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#[derive(Deserialize, Default)]
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#[serde(rename_all = "camelCase")]
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pub struct InitRequest {
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pub access_token: Option<String>,
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pub default_user: Option<String>,
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pub default_workdir: Option<String>,
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pub env_vars: Option<HashMap<String, String>>,
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pub hyperloop_ip: Option<String>,
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pub timestamp: Option<String>,
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pub volume_mounts: Option<Vec<VolumeMount>>,
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}
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#[derive(Deserialize)]
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pub struct VolumeMount {
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pub nfs_target: String,
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pub path: String,
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}
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/// POST /init — called by host agent after boot and after every resume.
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pub async fn post_init(
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State(state): State<Arc<AppState>>,
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body: Option<Json<InitRequest>>,
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) -> impl IntoResponse {
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let init_req = body.map(|b| b.0).unwrap_or_default();
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// Validate access token if provided
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if let Some(ref token_str) = init_req.access_token {
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if let Err(e) = validate_init_access_token(&state, token_str).await {
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tracing::error!(error = %e, "init: access token validation failed");
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return (StatusCode::UNAUTHORIZED, e).into_response();
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}
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}
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// Idempotent timestamp check
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if let Some(ref ts_str) = init_req.timestamp {
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if let Ok(ts) = chrono_parse_to_nanos(ts_str) {
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if !state.last_set_time.set_to_greater(ts) {
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// Stale request, skip data updates
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return trigger_restore_and_respond(&state).await;
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}
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}
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}
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// Apply env vars
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if let Some(ref vars) = init_req.env_vars {
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tracing::debug!(count = vars.len(), "setting env vars");
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for (k, v) in vars {
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state.defaults.env_vars.insert(k.clone(), v.clone());
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}
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}
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// Set access token
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if let Some(ref token_str) = init_req.access_token {
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if !token_str.is_empty() {
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tracing::debug!("setting access token");
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let _ = state.access_token.set(token_str.as_bytes());
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} else if state.access_token.is_set() {
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tracing::debug!("clearing access token");
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state.access_token.destroy();
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}
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}
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// Set default user
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if let Some(ref user) = init_req.default_user {
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if !user.is_empty() {
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tracing::debug!(user = %user, "setting default user");
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let mut defaults = state.defaults.clone();
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defaults.user = user.clone();
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// Note: In Rust we'd need interior mutability for this.
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// For now, env_vars (DashMap) handles concurrent access.
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// User/workdir mutation deferred to full state refactor.
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}
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}
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// Hyperloop /etc/hosts setup
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if let Some(ref ip) = init_req.hyperloop_ip {
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let ip = ip.clone();
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let env_vars = Arc::clone(&state.defaults.env_vars);
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tokio::spawn(async move {
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setup_hyperloop(&ip, &env_vars).await;
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});
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}
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// NFS mounts
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if let Some(ref mounts) = init_req.volume_mounts {
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for mount in mounts {
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let target = mount.nfs_target.clone();
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let path = mount.path.clone();
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tokio::spawn(async move {
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setup_nfs(&target, &path).await;
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});
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}
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}
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// Re-poll MMDS in background
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if state.is_fc {
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let env_vars = Arc::clone(&state.defaults.env_vars);
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let cancel = tokio_util::sync::CancellationToken::new();
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let cancel_clone = cancel.clone();
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tokio::spawn(async move {
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tokio::time::timeout(std::time::Duration::from_secs(60), async {
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mmds::poll_for_opts(env_vars, cancel_clone).await;
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})
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.await
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.ok();
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});
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}
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trigger_restore_and_respond(&state).await
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}
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async fn trigger_restore_and_respond(state: &AppState) -> axum::response::Response {
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// Safety net: if health check's postRestoreRecovery hasn't run yet
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if state
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.needs_restore
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.compare_exchange(true, false, Ordering::AcqRel, Ordering::Relaxed)
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.is_ok()
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{
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post_restore_recovery(state);
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}
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state.conn_tracker.restore_after_snapshot();
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if let Some(ref ps) = state.port_subsystem {
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ps.restart();
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}
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(
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StatusCode::NO_CONTENT,
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[(header::CACHE_CONTROL, "no-store")],
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)
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.into_response()
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}
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fn post_restore_recovery(state: &AppState) {
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tracing::info!("restore: post-restore recovery (no GC needed in Rust)");
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state.conn_tracker.restore_after_snapshot();
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if let Some(ref ps) = state.port_subsystem {
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ps.restart();
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tracing::info!("restore: port subsystem restarted");
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}
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}
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async fn validate_init_access_token(state: &AppState, request_token: &str) -> Result<(), String> {
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// Fast path: matches existing token
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if state.access_token.is_set() && !request_token.is_empty() && state.access_token.equals(request_token) {
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return Ok(());
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}
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// Check MMDS hash
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if state.is_fc {
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if let Ok(mmds_hash) = mmds::get_access_token_hash().await {
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if !mmds_hash.is_empty() {
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if request_token.is_empty() {
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let empty_hash = crypto::sha512::hash_access_token("");
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if mmds_hash == empty_hash {
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return Ok(());
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}
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} else {
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let token_hash = crypto::sha512::hash_access_token(request_token);
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if mmds_hash == token_hash {
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return Ok(());
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}
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}
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return Err("access token validation failed".into());
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}
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}
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}
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// First-time setup: no existing token and no MMDS
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if !state.access_token.is_set() {
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return Ok(());
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}
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if request_token.is_empty() {
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return Err("access token reset not authorized".into());
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}
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Err("access token validation failed".into())
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}
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async fn setup_hyperloop(address: &str, env_vars: &dashmap::DashMap<String, String>) {
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// Write to /etc/hosts: events.wrenn.local → address
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let entry = format!("{address} events.wrenn.local\n");
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match std::fs::read_to_string("/etc/hosts") {
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Ok(contents) => {
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let filtered: String = contents
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.lines()
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.filter(|line| !line.contains("events.wrenn.local"))
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.collect::<Vec<_>>()
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.join("\n");
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let new_contents = format!("{filtered}\n{entry}");
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if let Err(e) = std::fs::write("/etc/hosts", new_contents) {
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tracing::error!(error = %e, "failed to modify hosts file");
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return;
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}
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}
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Err(e) => {
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tracing::error!(error = %e, "failed to read hosts file");
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return;
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}
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}
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env_vars.insert(
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"WRENN_EVENTS_ADDRESS".into(),
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format!("http://{address}"),
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);
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}
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async fn setup_nfs(nfs_target: &str, path: &str) {
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let mkdir = tokio::process::Command::new("mkdir")
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.args(["-p", path])
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.output()
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.await;
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if let Err(e) = mkdir {
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tracing::error!(error = %e, path, "nfs: mkdir failed");
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return;
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}
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let mount = tokio::process::Command::new("mount")
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.args([
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"-v",
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"-t",
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"nfs",
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"-o",
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"mountproto=tcp,mountport=2049,proto=tcp,port=2049,nfsvers=3,noacl",
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nfs_target,
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path,
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])
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.output()
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.await;
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match mount {
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Ok(output) => {
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let stdout = String::from_utf8_lossy(&output.stdout);
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let stderr = String::from_utf8_lossy(&output.stderr);
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if output.status.success() {
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tracing::info!(nfs_target, path, stdout = %stdout, "nfs: mount success");
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} else {
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tracing::error!(nfs_target, path, stderr = %stderr, "nfs: mount failed");
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}
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}
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Err(e) => {
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tracing::error!(error = %e, nfs_target, path, "nfs: mount command failed");
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}
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}
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}
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fn chrono_parse_to_nanos(ts: &str) -> Result<i64, ()> {
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// Parse RFC3339 timestamp to nanoseconds since epoch
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// Simple approach: parse as seconds + fractional
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let secs = ts.parse::<f64>().ok();
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if let Some(s) = secs {
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return Ok((s * 1_000_000_000.0) as i64);
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}
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// Try RFC3339 format
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// For now, fall back to allowing the update
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Err(())
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}
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