chrs_sync/
lib.rs

1use chrono::Utc;
2/// chrs-sync crate provides synchronization utilities for the CHORUS system.
3///
4/// It uses a `Mailbox` for message passing between peers and a Dolt repository
5/// to track state hashes. The primary abstraction is `SyncManager`, which can
6/// broadcast the current repository hash to peers and handle incoming sync
7/// signals.
8use chrs_mail::{Mailbox, Message};
9use std::path::PathBuf;
10use std::process::Command;
11use uuid::Uuid;
12
13/// Manages synchronization of a Dolt repository across peers.
14///
15/// # Fields
16/// * `mailbox` – The `Mailbox` instance used to send and receive messages.
17/// * `repo_path` – Filesystem path to the local Dolt repository.
18///
19/// # Rationale
20/// The CHORUS architecture relies on deterministic state replication. By
21/// broadcasting the latest commit hash (`sync_signal`) each peer can decide
22/// whether to pull updates. This struct encapsulates that behaviour, keeping the
23/// rest of the system agnostic of the underlying VCS commands.
24pub struct SyncManager {
25    mailbox: Mailbox,
26    repo_path: PathBuf,
27}
28
29impl SyncManager {
30    /// Creates a new `SyncManager`.
31    ///
32    /// # Parameters
33    /// * `mailbox` – An already‑opened `Mailbox` for peer communication.
34    /// * `repo_path` – Path to the Dolt repository that should be kept in sync.
35    ///
36    /// Returns a fully‑initialised manager ready to broadcast or handle sync
37    /// signals.
38    pub fn new(mailbox: Mailbox, repo_path: PathBuf) -> Self {
39        Self { mailbox, repo_path }
40    }
41
42    /// Broadcasts the current repository state to a remote peer.
43    ///
44    /// The method executes `dolt log -n 1 --format %H` to obtain the most recent
45    /// commit hash, constructs a `Message` with topic `"sync_signal"` and sends it
46    /// via the mailbox.
47    ///
48    /// * `from_peer` – Identifier of the sender.
49    /// * `to_peer` – Identifier of the intended recipient.
50    ///
51    /// # Errors
52    /// Returns any I/O or command‑execution error wrapped in a boxed `dyn
53    /// Error`.
54    pub fn broadcast_state(
55        &self,
56        from_peer: &str,
57        to_peer: &str,
58    ) -> Result<(), Box<dyn std::error::Error>> {
59        // Get current dolt hash
60        let output = Command::new("dolt")
61            .args(&["log", "-n", "1", "--format", "%H"])
62            .current_dir(&self.repo_path)
63            .output()?;
64
65        let current_hash = String::from_utf8_lossy(&output.stdout).trim().to_string();
66
67        let msg = Message {
68            id: Uuid::new_v4(),
69            from_peer: from_peer.into(),
70            to_peer: to_peer.into(),
71            topic: "sync_signal".into(),
72            payload: serde_json::json!({ "commit_hash": current_hash }),
73            sent_at: Utc::now(),
74            read_at: None,
75        };
76
77        self.mailbox.send(&msg)?;
78        println!(
79            "Broadcasted sync signal: {} from {}",
80            current_hash, from_peer
81        );
82        Ok(())
83    }
84
85    /// Handles an incoming `sync_signal` message.
86    ///
87    /// If the message topic is not `"sync_signal"` the function returns `Ok(())`
88    /// immediately. Otherwise it extracts the remote commit hash and attempts a
89    /// `dolt pull origin` to bring the local repository up‑to‑date. In a real
90    /// P2P deployment the remote URL would be derived from the sender, but the
91    /// current implementation uses the default remote configuration.
92    ///
93    /// # Errors
94    /// Propagates any command execution failures.
95    pub fn handle_sync_signal(&self, msg: &Message) -> Result<(), Box<dyn std::error::Error>> {
96        if msg.topic != "sync_signal" {
97            return Ok(());
98        }
99
100        let remote_hash = msg.payload["commit_hash"].as_str().unwrap_or_default();
101        println!("Received sync signal for hash: {}", remote_hash);
102
103        // In a real P2P scenario, we would pull from the remote peer's URL.
104        // For now, we simulate by attempting a 'dolt pull' if a remote is configured.
105        let status = Command::new("dolt")
106            .args(&["pull", "origin"])
107            .current_dir(&self.repo_path)
108            .status()?;
109
110        if status.success() {
111            println!("Successfully pulled updates for hash: {}", remote_hash);
112        }
113
114        Ok(())
115    }
116}
chrs_sync/lib.rs

chrs_sync/
lib.rs
