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Merged
Yashb404 merged 4 commits into from
Feb 13, 2026
Merged

Restore sessions from Docker container metadata after server restart #142

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dc0fc56
Initial plan
Copilot Feb 13, 2026
efc7f0b
Implement session restoration from Docker containers
Copilot Feb 13, 2026
773b3be
Security: sanitize Docker error messages sent to clients
Copilot Feb 13, 2026
2d7d9a3
Address code review feedback
Copilot Feb 13, 2026
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5 changes: 5 additions & 0 deletions server/src/main.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -16,6 +16,7 @@ mod handlers {
}

use services::docker::start_background_reaper;
use services::websocket::restore_sessions_from_containers;

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
Expand All @@ -24,6 +25,10 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
// Setup database and Docker
let state = config::setup_database_and_docker().await?;

// Restore sessions from existing Docker containers (critical for reconnecting to pre-existing containers)
tracing::info!("Restoring sessions from existing containers...");
restore_sessions_from_containers(&state).await;

// Spawn background reaper
let docker_reaper = state.docker.clone();
let sessions_reaper = state.sessions.clone();
Expand Down
245 changes: 225 additions & 20 deletions server/src/services/websocket.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -3,7 +3,7 @@ use axum::{
response::Response,
http::StatusCode,
};
use bollard::container::{CreateContainerOptions, Config};
use bollard::container::{CreateContainerOptions, Config, ListContainersOptions};
use bollard::models::{HostConfig, Mount, MountTypeEnum, MountTmpfsOptions};
use bollard::image::CreateImageOptions;
use bollard::exec::{CreateExecOptions, StartExecResults};
Expand All @@ -16,6 +16,116 @@ use tower_sessions::Session;
use crate::state::{AppState, SessionContext};
use crate::models::{User, AnalyticsEventType, log_analytics_event};

/// Helper function to create container labels with session metadata for restoration
fn create_container_labels(
session_id: &str,
owner_id: Option<i64>,
project_owner_id: Option<i64>,
project_slug: Option<&str>,
shell: &str,
container_type: &str, // "builder" or "viewer"
) -> HashMap<String, String> {
let mut labels = HashMap::from([
("managed_by".to_string(), "TryCli Studio".to_string()),
("session_id".to_string(), session_id.to_string()),
("shell".to_string(), shell.to_string()),
("container_type".to_string(), container_type.to_string()),
]);

if let Some(id) = owner_id {
labels.insert("owner_id".to_string(), id.to_string());
}

if let Some(id) = project_owner_id {
labels.insert("project_owner_id".to_string(), id.to_string());
}

if let Some(slug) = project_slug {
labels.insert("project_slug".to_string(), slug.to_string());
}

labels
}

/// Restore sessions from existing Docker containers on server startup
/// This allows pre-existing containers to be reconnected after server restart
pub async fn restore_sessions_from_containers(state: &AppState) {
let filters = HashMap::from([
("label".to_string(), vec!["managed_by=TryCli Studio".to_string()])
]);

let opts = ListContainersOptions {
all: false, // Only running containers
filters,
..Default::default()
};

match state.docker.list_containers(Some(opts)).await {
Ok(containers) => {
let mut restored = 0;
for container in containers {
if let Some(labels) = container.labels {
// Extract session metadata from labels
let session_id = labels.get("session_id").map(|s| s.clone());
let shell = labels.get("shell").map(|s| s.clone()).unwrap_or_else(|| "/bin/bash".to_string());
let owner_id = labels.get("owner_id").and_then(|s| s.parse::<i64>().ok());
let project_owner_id = labels.get("project_owner_id").and_then(|s| s.parse::<i64>().ok());
let project_slug = labels.get("project_slug").map(|s| s.clone());

if let (Some(session_id), Some(names)) = (session_id, container.names) {
let container_name = names.first()
.map(|n| n.trim_start_matches('/').to_string())
.unwrap_or_default();

if !container_name.is_empty() {
// Restore session to in-memory map
let mut map = state.lock_sessions();

// Only restore if not already present (shouldn't happen, but be defensive)
if !map.contains_key(&session_id) {
// Calculate elapsed time from container creation
let created_at = if let Some(created_ts) = container.created {
// Container age in seconds
let now = std::time::SystemTime::now()
.duration_since(std::time::UNIX_EPOCH)
.unwrap()
.as_secs() as i64;
let age_secs = now - created_ts;

// Set created_at to approximate original time
std::time::Instant::now()
.checked_sub(std::time::Duration::from_secs(age_secs.max(0) as u64))
.unwrap_or_else(|| std::time::Instant::now())
} else {
std::time::Instant::now()
};

map.insert(session_id.clone(), SessionContext {
container_name: container_name.clone(),
shell,
pending_image_tag: None,
owner_id,
project_owner_id,
is_publishing: false,
project_slug,
created_at,
is_ws_connected: false, // Will be set to true on reconnection
});
restored += 1;
tracing::info!("Restored session {} with container {}", session_id, container_name);
}
}
}
}
}
tracing::info!("Session restoration complete: {} sessions restored", restored);
}
Err(e) => {
tracing::error!("Failed to restore sessions from containers: {}", e);
}
}
}

pub async fn ws_handler(
ws: WebSocketUpgrade,
Path(session_id): Path<String>,
Expand All @@ -25,6 +135,17 @@ pub async fn ws_handler(
let user: Option<User> = session.get("user").await.map_err(|_| StatusCode::INTERNAL_SERVER_ERROR)?;
let user_id = user.map(|u| u.id);

// Check if session exists in memory, if not, try to restore from Docker
let session_exists = {
let map = state.lock_sessions();
map.contains_key(&session_id)
};

if !session_exists {
// Try to find and restore this specific session from Docker containers
restore_specific_session(&state, &session_id).await;
}

{
let map = state.lock_sessions();

Expand All @@ -47,6 +168,72 @@ pub async fn ws_handler(
Ok(ws.on_upgrade(move |socket| handle_socket(socket, state, session_id, user_id)))
}

/// Attempt to restore a specific session from Docker containers
/// This is called when a client tries to connect to a session that isn't in memory
async fn restore_specific_session(state: &AppState, session_id: &str) {
let filters = HashMap::from([
("label".to_string(), vec![
"managed_by=TryCli Studio".to_string(),
format!("session_id={}", session_id)
])
]);

let opts = ListContainersOptions {
all: false, // Only running containers
filters,
..Default::default()
};

if let Ok(containers) = state.docker.list_containers(Some(opts)).await {
for container in containers {
if let Some(labels) = container.labels {
let shell = labels.get("shell").map(|s| s.clone()).unwrap_or_else(|| "/bin/bash".to_string());
let owner_id = labels.get("owner_id").and_then(|s| s.parse::<i64>().ok());
let project_owner_id = labels.get("project_owner_id").and_then(|s| s.parse::<i64>().ok());
let project_slug = labels.get("project_slug").map(|s| s.clone());

if let Some(names) = container.names {
let container_name = names.first()
.map(|n| n.trim_start_matches('/').to_string())
.unwrap_or_default();

if !container_name.is_empty() {
// Calculate elapsed time from container creation
let created_at = if let Some(created_ts) = container.created {
let now = std::time::SystemTime::now()
.duration_since(std::time::UNIX_EPOCH)
.unwrap()
.as_secs() as i64;
let age_secs = now - created_ts;

std::time::Instant::now()
.checked_sub(std::time::Duration::from_secs(age_secs.max(0) as u64))
.unwrap_or_else(|| std::time::Instant::now())
} else {
std::time::Instant::now()
};

let mut map = state.lock_sessions();
map.insert(session_id.to_string(), SessionContext {
container_name: container_name.clone(),
shell,
pending_image_tag: None,
owner_id,
project_owner_id,
is_publishing: false,
project_slug,
created_at,
is_ws_connected: false,
});
tracing::info!("Restored session {} from container {}", session_id, container_name);
return;
}
}
}
}
}
}

async fn handle_socket(mut socket: WebSocket, state: AppState, session_id: String, user_id: Option<i64>) {

// Track if this is a first-time connection for view counting
Expand Down Expand Up @@ -103,7 +290,13 @@ async fn handle_socket(mut socket: WebSocket, state: AppState, session_id: Strin
if let Some(ctx) = map.get(&session_id) {
// If we have an image tag but no container name, it's a viewer waiting to start
if ctx.container_name.is_empty() && ctx.pending_image_tag.is_some() {
Some((ctx.pending_image_tag.clone().unwrap(), ctx.shell.clone()))
Some((
ctx.pending_image_tag.clone().unwrap(),
ctx.shell.clone(),
ctx.owner_id,
ctx.project_owner_id,
ctx.project_slug.clone(),
))
} else {
None
}
Expand All @@ -112,15 +305,22 @@ async fn handle_socket(mut socket: WebSocket, state: AppState, session_id: Strin
}
};

if let Some((image_tag, shell)) = pending_spawn {
if let Some((image_tag, shell, owner_id, project_owner_id, project_slug)) = pending_spawn {
// Perform the spawn that used to be in get_project
let container_name = format!("trycli-studio-viewer-{}", Uuid::new_v4());

let labels = create_container_labels(
&session_id,
owner_id,
project_owner_id,
project_slug.as_deref(),
&shell,
"viewer",
);

let config = Config {
image: Some(image_tag),
labels: Some(HashMap::from([
("managed_by".to_string(), "TryCli Studio".to_string())
])),
labels: Some(labels),
tty: Some(true),
user: Some("root".to_string()),
// FIX: Run sleep infinity as PID 1. This uses almost 0 CPU/RAM.
Expand Down Expand Up @@ -190,12 +390,10 @@ async fn handle_socket(mut socket: WebSocket, state: AppState, session_id: Strin
if let Err(e) =
state.docker.start_container::<String>(&container_name, None).await
{
// Surface detailed error to client and logs
let msg = format!(
"\r\n\x1b[31m[!] Failed to start viewer container: {}\x1b[0m\r\n",
e
);
eprintln!("Viewer start error for session {}: {}", session_id, e);
// Log detailed error server-side only
tracing::error!("Viewer start error for session {}: {}", session_id, e);
// Send generic error message to client
let msg = "\r\n\x1b[31m[!] Failed to start viewer container. Please try again later.\x1b[0m\r\n";
let _ = socket.send(Message::Text(msg.into())).await;
return;
}
Expand All @@ -208,11 +406,10 @@ async fn handle_socket(mut socket: WebSocket, state: AppState, session_id: Strin
}
}
Err(e) => {
let msg = format!(
"\r\n\x1b[31m[!] Failed to create viewer container: {}\x1b[0m\r\n",
e
);
eprintln!("Viewer create error for session {}: {}", session_id, e);
// Log detailed error server-side only
tracing::error!("Viewer create error for session {}: {}", session_id, e);
// Send generic error message to client
let msg = "\r\n\x1b[31m[!] Failed to create viewer container. Please try again later.\x1b[0m\r\n";
let _ = socket.send(Message::Text(msg.into())).await;
return;
}
Expand Down Expand Up @@ -332,6 +529,16 @@ async fn run_setup_wizard(mut socket: WebSocket, state: AppState, session_id: St
}

let container_name = format!("trycli-studio-session-{}", Uuid::new_v4());

let labels = create_container_labels(
&session_id,
_user_id,
None, // Builder sessions don't have project context yet
None,
final_shell,
"builder",
);

let config = Config {
image: Some(image.to_string()),
tty: Some(true),
Expand All @@ -343,9 +550,7 @@ async fn run_setup_wizard(mut socket: WebSocket, state: AppState, session_id: St
"LC_ALL=C.UTF-8".to_string(),
"TERM=xterm-256color".to_string()
]),
labels: Some(HashMap::from([
("managed_by".to_string(), "TryCli Studio".to_string())
])),
labels: Some(labels),
host_config: Some(HostConfig {
runtime: Some("runsc".to_string()),
memory: Some(512 * 1024 * 1024),
Expand Down