Files
archy/core/archipelago/src/container/migration_backup.rs
T

255 lines
9.2 KiB
Rust

//! Consistent, private snapshots for declaratively opted-in runtime migrations.
use anyhow::{bail, Context, Result};
use archipelago_container::AppManifest;
use std::os::unix::fs::PermissionsExt;
use std::path::{Path, PathBuf};
pub fn enabled(manifest: &AppManifest) -> Result<bool> {
match manifest.app.extensions.get("backup_before_runtime_change") {
None => Ok(false),
Some(value) => value
.as_bool()
.context("backup_before_runtime_change must be boolean"),
}
}
fn relative_sources(manifest: &AppManifest, data_dir: &Path) -> Result<Vec<PathBuf>> {
let mut sources = Vec::new();
for volume in &manifest.app.volumes {
if volume.options.iter().any(|v| v == "ro") || volume.volume_type == "tmpfs" {
continue;
}
// A runtime socket is a connection, not application state.
if volume.source == "/run/user/1000/podman/podman.sock" {
continue;
}
if volume.volume_type != "bind" {
bail!("runtime migration backup requires bind-mounted persistent state");
}
let path = Path::new(&volume.source);
let relative = path
.strip_prefix(data_dir)
.context("runtime migration state must be inside the node data directory")?;
if relative.starts_with("migration-backups") {
bail!("migration backup cannot include its own archive directory");
}
if relative.as_os_str().is_empty()
|| relative
.components()
.any(|c| !matches!(c, std::path::Component::Normal(_)))
{
bail!("invalid runtime migration state path");
}
sources.push(relative.to_path_buf());
}
sources.sort();
sources.dedup();
let mut roots: Vec<PathBuf> = Vec::new();
for source in sources {
if !roots.iter().any(|root| source.starts_with(root)) {
roots.push(source);
}
}
if roots.is_empty() {
bail!("runtime migration backup has no persistent state mounts");
}
Ok(roots)
}
/// Caller must gracefully stop the app before this function, and resume the old
/// service if it fails. No source files are changed or deleted by this operation.
pub async fn snapshot(
manifest: &AppManifest,
data_dir: &Path,
previous_unit: Option<&[u8]>,
) -> Result<PathBuf> {
let mut command = tokio::process::Command::new("podman");
command.args(["unshare", "tar"]);
snapshot_with_command(manifest, data_dir, previous_unit, command).await
}
async fn snapshot_with_command(
manifest: &AppManifest,
data_dir: &Path,
previous_unit: Option<&[u8]>,
mut command: tokio::process::Command,
) -> Result<PathBuf> {
let sources = relative_sources(manifest, data_dir)?;
let canonical_root = tokio::fs::canonicalize(data_dir).await?;
for source in &sources {
let path = data_dir.join(source);
if tokio::fs::symlink_metadata(&path)
.await?
.file_type()
.is_symlink()
{
bail!("runtime migration state mount is a symlink; explicit backup required");
}
let canonical = tokio::fs::canonicalize(&path).await?;
if !canonical.starts_with(&canonical_root) {
bail!("runtime migration state path resolves outside node data directory");
}
}
let root = data_dir.join("migration-backups");
tokio::fs::create_dir_all(&root).await?;
tokio::fs::set_permissions(&root, std::fs::Permissions::from_mode(0o700)).await?;
let dir = root.join(uuid::Uuid::new_v4().to_string());
tokio::fs::create_dir(&dir).await?;
tokio::fs::set_permissions(&dir, std::fs::Permissions::from_mode(0o700)).await?;
if let Some(unit) = previous_unit {
let path = dir.join("previous.container");
tokio::fs::write(&path, unit).await?;
tokio::fs::set_permissions(&path, std::fs::Permissions::from_mode(0o600)).await?;
tokio::fs::File::open(&path).await?.sync_all().await?;
}
let partial = dir.join("state.tar.partial");
let archive = dir.join("state.tar");
let output = command
.args([
"--create",
"--numeric-owner",
"--acls",
"--xattrs",
"--file",
])
.arg(&partial)
.arg("--directory")
.arg(data_dir)
.arg("--")
.args(&sources)
.output()
.await
.context("start rootless migration snapshot")?;
if !output.status.success() {
// No tar stderr in public logs: it can contain private filenames.
let _ = tokio::fs::remove_file(&partial).await;
bail!("persistent-state snapshot failed; original state was left intact");
}
tokio::fs::set_permissions(&partial, std::fs::Permissions::from_mode(0o600)).await?;
tokio::fs::File::open(&partial).await?.sync_all().await?;
tokio::fs::rename(&partial, &archive).await?;
let metadata = serde_json::json!({"app": manifest.app.id, "version": manifest.app.version,
"network": manifest.app.container.network, "capabilities": manifest.app.security.capabilities, "sources": sources});
tokio::fs::write(
dir.join("metadata.json"),
serde_json::to_vec_pretty(&metadata)?,
)
.await?;
tokio::fs::File::open(&dir).await?.sync_all().await?;
Ok(archive)
}
#[cfg(test)]
mod tests {
use super::*;
fn portainer() -> AppManifest {
AppManifest::parse(include_str!("../../../../apps/portainer/manifest.yml")).unwrap()
}
#[tokio::test]
async fn stopped_state_archive_round_trips_database_compose_and_old_unit() {
let dir = tempfile::tempdir().unwrap();
let state = dir.path().join("portainer");
tokio::fs::create_dir_all(state.join("compose"))
.await
.unwrap();
tokio::fs::write(state.join("portainer.db"), b"fixture database")
.await
.unwrap();
tokio::fs::write(state.join("compose/stack.yml"), b"services: {}\n")
.await
.unwrap();
let mut m = portainer();
m.app.volumes[0].source = state.display().to_string();
m.app.volumes[1].source = state.join("compose").display().to_string();
let archive = snapshot_with_command(
&m,
dir.path(),
Some(b"old unit"),
tokio::process::Command::new("tar"),
)
.await
.unwrap();
assert_eq!(
std::fs::metadata(&archive).unwrap().permissions().mode() & 0o777,
0o600
);
assert_eq!(
tokio::fs::read(archive.parent().unwrap().join("previous.container"))
.await
.unwrap(),
b"old unit"
);
let restored = tempfile::tempdir().unwrap();
assert!(tokio::process::Command::new("tar")
.arg("-xf")
.arg(archive)
.arg("-C")
.arg(restored.path())
.status()
.await
.unwrap()
.success());
assert_eq!(
tokio::fs::read(restored.path().join("portainer/portainer.db"))
.await
.unwrap(),
b"fixture database"
);
assert_eq!(
tokio::fs::read(restored.path().join("portainer/compose/stack.yml"))
.await
.unwrap(),
b"services: {}\n"
);
assert_eq!(
tokio::fs::read(state.join("portainer.db")).await.unwrap(),
b"fixture database"
);
}
#[tokio::test]
async fn failed_snapshot_never_publishes_archive_or_changes_original_state() {
let dir = tempfile::tempdir().unwrap();
let state = dir.path().join("portainer");
tokio::fs::create_dir_all(state.join("compose"))
.await
.unwrap();
tokio::fs::write(state.join("portainer.db"), b"unchanged")
.await
.unwrap();
let mut m = portainer();
m.app.volumes[0].source = state.display().to_string();
m.app.volumes[1].source = state.join("compose").display().to_string();
assert!(
snapshot_with_command(&m, dir.path(), None, tokio::process::Command::new("false"))
.await
.is_err()
);
assert_eq!(
tokio::fs::read(state.join("portainer.db")).await.unwrap(),
b"unchanged"
);
for entry in std::fs::read_dir(dir.path().join("migration-backups")).unwrap() {
assert!(!entry.unwrap().path().join("state.tar").exists());
}
}
#[test]
fn backup_covers_all_portainer_state_once_and_excludes_runtime_socket() {
let m = portainer();
assert!(enabled(&m).unwrap());
assert_eq!(
relative_sources(&m, Path::new("/var/lib/archipelago")).unwrap(),
vec![PathBuf::from("portainer")]
);
}
#[test]
fn backup_refuses_unknown_state_locations_instead_of_silently_omitting_them() {
let mut m = portainer();
m.app.volumes[0].source = "/other/operator/state".into();
assert!(relative_sources(&m, Path::new("/var/lib/archipelago")).is_err());
m.app.volumes[0].source = "/var/lib/archipelago/../secret".into();
assert!(relative_sources(&m, Path::new("/var/lib/archipelago")).is_err());
}
}