[WIP] Daemon & CLI

iota-updater/src/transaction.rs

@@ -0,0 +1,79 @@
+use crate::manifest::{Artifact, verify_artifact};
+use anyhow::{Context, Result};
+use std::{
+    fs,
+    path::{Path, PathBuf},
+};
+
+#[derive(Clone, Debug)]
+pub struct UpdateTransaction {
+    pub root: PathBuf,
+    pub staging: PathBuf,
+}
+impl UpdateTransaction {
+    pub fn new(root: impl Into<PathBuf>) -> Self {
+        let root = root.into();
+        Self {
+            staging: root.join(".staging"),
+            root,
+        }
+    }
+    pub fn acquire(&self) -> Result<fs::File> {
+        fs::create_dir_all(&self.root)?;
+        let path = self.root.join("update.lock");
+        let file = fs::OpenOptions::new()
+            .write(true)
+            .create_new(true)
+            .open(path)
+            .context("update already in progress")?;
+        Ok(file)
+    }
+    pub fn stage_artifact(&self, source: &Path, artifact: &Artifact) -> Result<PathBuf> {
+        fs::create_dir_all(&self.staging)?;
+        let target = self.staging.join(&artifact.path);
+        if let Some(parent) = target.parent() {
+            fs::create_dir_all(parent)?;
+        }
+        fs::copy(source, &target)?;
+        verify_artifact(&target, artifact)?;
+        Ok(target)
+    }
+    pub fn activate(&self, version: &str) -> Result<()> {
+        let version_dir = self.root.join("versions").join(version);
+        fs::create_dir_all(version_dir.parent().unwrap())?;
+        fs::rename(&self.staging, &version_dir).context("activate staged release")?;
+        let current_tmp = self.root.join("current.new");
+        let _ = fs::remove_file(&current_tmp);
+        std::os::unix::fs::symlink(&version_dir, &current_tmp)?;
+        fs::rename(current_tmp, self.root.join("current"))?;
+        Ok(())
+    }
+    pub fn rollback(&self, previous: &str) -> Result<()> {
+        let current = self.root.join("current");
+        let tmp = self.root.join("current.rollback");
+        let _ = fs::remove_file(&tmp);
+        std::os::unix::fs::symlink(self.root.join("versions").join(previous), &tmp)?;
+        fs::rename(tmp, current)?;
+        Ok(())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    #[test]
+    fn lock_is_exclusive_and_activation_switches_current() {
+        let dir = tempfile::tempdir().unwrap();
+        let tx = UpdateTransaction::new(dir.path());
+        let lock = tx.acquire().unwrap();
+        assert!(tx.acquire().is_err());
+        drop(lock);
+        std::fs::create_dir_all(&tx.staging).unwrap();
+        std::fs::write(tx.staging.join("manifest.json"), b"ok").unwrap();
+        tx.activate("1.0.0").unwrap();
+        assert_eq!(
+            std::fs::read_to_string(dir.path().join("current/manifest.json")).unwrap(),
+            "ok"
+        );
+    }
+}