engram_core/
server.rs

1use std::path::{Path, PathBuf};
2use std::sync::{Arc, Mutex, RwLock};
3
4use tokio::io::{AsyncBufReadExt, AsyncWriteExt, BufReader};
5use tokio::net::UnixListener;
6use tokio::signal::unix::{SignalKind, signal};
7
8use engram_embeddings::Embedder;
9use engram_llm_client::{EmbeddingProvider, TextGenerator};
10use engram_router::Router;
11use engram_storage::Database;
12
13use crate::config::{self, Config};
14use crate::dispatch;
15use crate::error::CoreError;
16use crate::indexes::IndexSet;
17use crate::protocol::{JsonRequest, JsonResponse};
18
19const PROJECT_DB_RELATIVE: &str = ".engram/engram.db";
20const PROJECT_SOCKET_RELATIVE: &str = ".engram/engram.sock";
21
22const ROUTER_DEFAULT_ALPHA: f32 = 0.1;
23const ROUTER_DEFAULT_EPSILON: f32 = 0.15;
24
25pub struct ServerState {
26    pub database: Mutex<Database>,
27    pub indexes: RwLock<IndexSet>,
28    pub embedder: Embedder,
29    pub router: Mutex<Router>,
30    pub config: Config,
31    pub database_path: String,
32    pub embedding_provider: Arc<dyn EmbeddingProvider + Send + Sync>,
33    pub text_generator: Option<Arc<dyn TextGenerator + Send + Sync>>,
34}
35
36pub async fn run(config: Config) -> Result<(), CoreError> {
37    let cwd = std::env::current_dir()
38        .map_err(|error| CoreError::SocketError(format!("cwd unavailable: {error}")))?;
39    let home = home_dir_or_error()?;
40    let project_dir = config::resolve_project_dir(&cwd, None)?;
41    // See execute_command in main.rs for why this construction has to run on
42    // the blocking pool. reqwest::blocking::ClientBuilder::build internally
43    // spins up and drops a current-thread tokio runtime; doing that on the
44    // outer multi-threaded runtime's worker panics.
45    let state = {
46        let config = config.clone();
47        let project_dir = project_dir.clone();
48        let home = home.clone();
49        tokio::task::spawn_blocking(move || initialize_state(&config, &project_dir, &home))
50            .await
51            .map_err(|error| CoreError::SocketError(error.to_string()))??
52    };
53    {
54        let database = state.database.lock().unwrap();
55        let configured_model = config
56            .embedding
57            .model
58            .as_deref()
59            .unwrap_or(config::DEFAULT_EMBEDDING_MODEL);
60        crate::migrations::embedding_model_v1::check(&database, configured_model)?;
61    }
62    warn_missing_api_keys(&config);
63    let shared_state = Arc::new(state);
64    let socket_path = resolve_socket_path(&project_dir, &config)?;
65    cleanup_stale_socket(&socket_path);
66    let listener = bind_listener(&socket_path)?;
67    accept_loop(listener, shared_state).await
68}
69
70pub fn check_legacy_database(project_dir: &Path, home_dir: &Path) -> Result<(), CoreError> {
71    let project_db = project_dir.join(PROJECT_DB_RELATIVE);
72    let home_db = home_dir.join(PROJECT_DB_RELATIVE);
73    if !project_db.exists() && home_db.exists() {
74        return Err(CoreError::LegacyDatabaseDetected {
75            legacy_path: home_db.to_string_lossy().to_string(),
76            project_path: project_dir.to_string_lossy().to_string(),
77        });
78    }
79    Ok(())
80}
81
82pub(crate) fn initialize_state(
83    config: &Config,
84    project_dir: &Path,
85    home_dir: &Path,
86) -> Result<ServerState, CoreError> {
87    check_legacy_database(project_dir, home_dir)?;
88    let database_path = resolve_database_path(project_dir);
89    let database = Database::open(&database_path)?;
90    crate::migrations::run_pending(&database)?;
91    let embedding_provider: Arc<dyn EmbeddingProvider + Send + Sync> =
92        Arc::from(config.build_embedding_provider()?);
93    let text_generator: Option<Arc<dyn TextGenerator + Send + Sync>> =
94        match config.build_text_generator() {
95            Ok(generator) => Some(Arc::from(generator)),
96            Err(error) => {
97                eprintln!("warning: text generator unavailable, running in degraded mode: {error}");
98                None
99            }
100        };
101    let hnsw_config = config.clone();
102    let indexes = crate::persistence::load_or_rebuild(
103        &resolve_index_directory(&database_path),
104        &database,
105        || hnsw_config.build_hnsw_params(),
106    )?;
107    let embedder = Embedder::new(config.embedding.hyde_threshold);
108    let router = Router::new(ROUTER_DEFAULT_ALPHA, ROUTER_DEFAULT_EPSILON);
109    Ok(ServerState {
110        database: Mutex::new(database),
111        indexes: RwLock::new(indexes),
112        embedder,
113        router: Mutex::new(router),
114        config: config.clone(),
115        database_path,
116        embedding_provider,
117        text_generator,
118    })
119}
120
121fn resolve_database_path(project_dir: &Path) -> String {
122    if let Ok(value) = std::env::var("ENGRAM_DB_PATH") {
123        return value;
124    }
125    project_dir
126        .join(PROJECT_DB_RELATIVE)
127        .to_string_lossy()
128        .to_string()
129}
130
131fn resolve_socket_path(project_dir: &Path, config: &Config) -> Result<String, CoreError> {
132    if let Ok(value) = std::env::var("ENGRAM_SOCKET_PATH") {
133        return Ok(value);
134    }
135    // Prefer project socket when the `.engram/` dir exists (walk-up already validated this).
136    if project_dir.join(".engram").is_dir() {
137        return Ok(project_dir
138            .join(PROJECT_SOCKET_RELATIVE)
139            .to_string_lossy()
140            .to_string());
141    }
142    match config.server.socket_path.as_deref() {
143        Some(fallback) => Ok(expand_tilde(fallback)),
144        None => Err(CoreError::SocketError(
145            "no socket path available: no project .engram/ marker found, \
146             ENGRAM_SOCKET_PATH not set, and server.socket_path not configured"
147                .into(),
148        )),
149    }
150}
151
152fn home_dir_or_error() -> Result<PathBuf, CoreError> {
153    match std::env::var("HOME") {
154        Ok(value) if !value.is_empty() => Ok(PathBuf::from(value)),
155        _ => Err(CoreError::InitFailed(
156            "HOME environment variable not set".into(),
157        )),
158    }
159}
160
161pub(crate) fn resolve_index_directory(database_path: &str) -> String {
162    std::path::Path::new(database_path)
163        .parent()
164        .map(|parent| parent.to_string_lossy().to_string())
165        .unwrap_or_else(|| ".".to_string())
166}
167
168fn cleanup_stale_socket(socket_path: &str) {
169    let _ = std::fs::remove_file(socket_path);
170}
171
172fn bind_listener(socket_path: &str) -> Result<UnixListener, CoreError> {
173    if let Some(parent) = std::path::Path::new(socket_path).parent() {
174        std::fs::create_dir_all(parent)
175            .map_err(|error| CoreError::SocketError(error.to_string()))?;
176    }
177    UnixListener::bind(socket_path).map_err(|error| CoreError::SocketError(error.to_string()))
178}
179
180async fn accept_loop(listener: UnixListener, state: Arc<ServerState>) -> Result<(), CoreError> {
181    let mut sigterm =
182        signal(SignalKind::terminate()).map_err(|e| CoreError::SocketError(e.to_string()))?;
183    spawn_background_reindex(Arc::clone(&state));
184    loop {
185        tokio::select! {
186            accept_result = listener.accept() => {
187                let (stream, _address) = accept_result
188                    .map_err(|error| CoreError::SocketError(error.to_string()))?;
189                let client_state = Arc::clone(&state);
190                tokio::spawn(async move {
191                    if let Err(error) = handle_client(stream, client_state).await {
192                        eprintln!("client error: {error}");
193                    }
194                });
195            }
196            _ = sigterm.recv() => {
197                return save_indexes_on_shutdown(&state);
198            }
199        }
200    }
201}
202
203fn spawn_background_reindex(state: Arc<ServerState>) {
204    let interval_secs = state.config.server.reindex_interval_secs;
205    if interval_secs == 0 {
206        return;
207    }
208    tokio::spawn(async move {
209        let mut interval = tokio::time::interval(std::time::Duration::from_secs(interval_secs));
210        interval.tick().await; // skip first immediate tick
211        loop {
212            interval.tick().await;
213            let reindex_state = Arc::clone(&state);
214            let _ = tokio::task::spawn_blocking(move || {
215                reindex_unindexed_memories(&reindex_state);
216            })
217            .await;
218        }
219    });
220}
221
222/// Reindex unindexed memories from SQLite into the HNSW index.
223///
224/// **Unstable:** exposed for latency benchmarking only
225/// (`crates/engram-core/tests/search_latency_bench.rs`). Not part of the public
226/// API contract; may change or be removed without notice.
227#[doc(hidden)]
228pub fn reindex_unindexed_memories(state: &ServerState) {
229    let database = state.database.lock().unwrap();
230    let unindexed = match query_unindexed_ids(&database) {
231        Ok(ids) => ids,
232        Err(_) => return,
233    };
234    if unindexed.is_empty() {
235        return;
236    }
237    let mut indexes = state.indexes.write().unwrap();
238    for memory_id in &unindexed {
239        let _ = reindex_single_memory(&database, &mut indexes, memory_id);
240    }
241}
242
243fn query_unindexed_ids(database: &Database) -> Result<Vec<String>, CoreError> {
244    let mut statement = database
245        .connection()
246        .prepare(
247            "SELECT id FROM memories WHERE indexed = 0 \
248             AND embedding_context IS NOT NULL LIMIT 100",
249        )
250        .map_err(|e| CoreError::Storage(engram_storage::StorageError::from(e)))?;
251    let rows = statement
252        .query_map([], |row| row.get::<_, String>(0))
253        .map_err(|e| CoreError::Storage(engram_storage::StorageError::from(e)))?;
254    let ids: Vec<String> = rows.flatten().collect();
255    Ok(ids)
256}
257
258fn reindex_single_memory(
259    database: &Database,
260    indexes: &mut IndexSet,
261    memory_id: &str,
262) -> Result<(), CoreError> {
263    let memory = database.get_memory(memory_id)?;
264    let embedding = crate::persistence::extract_embeddings_from_memory(&memory)?;
265    let id_hash = crate::persistence::hash_string_to_u64(memory_id);
266    let rng_value = crate::persistence::deterministic_rng(id_hash);
267    if !indexes.contains(id_hash) {
268        indexes.insert(id_hash, memory_id, &embedding, rng_value)?;
269    }
270    database.set_memory_indexed(memory_id, true)?;
271    Ok(())
272}
273
274async fn handle_client(
275    stream: tokio::net::UnixStream,
276    state: Arc<ServerState>,
277) -> Result<(), CoreError> {
278    let (reader, mut writer) = stream.into_split();
279    let mut lines = BufReader::new(reader).lines();
280    while let Some(line) = lines
281        .next_line()
282        .await
283        .map_err(|error| CoreError::SocketError(error.to_string()))?
284    {
285        let response = process_request_line(&line, &state).await;
286        let serialized = serde_json::to_string(&response)
287            .map_err(|error| CoreError::SocketError(error.to_string()))?;
288        writer
289            .write_all(serialized.as_bytes())
290            .await
291            .map_err(|error| CoreError::SocketError(error.to_string()))?;
292        writer
293            .write_all(b"\n")
294            .await
295            .map_err(|error| CoreError::SocketError(error.to_string()))?;
296    }
297    Ok(())
298}
299
300async fn process_request_line(line: &str, state: &Arc<ServerState>) -> JsonResponse {
301    let request: JsonRequest = match serde_json::from_str(line) {
302        Ok(parsed) => parsed,
303        Err(error) => {
304            return JsonResponse::error(String::new(), 4000, format!("invalid json: {error}"));
305        }
306    };
307    let request_id = request.id.clone();
308    match dispatch::route(&request.method, state, request.params).await {
309        Ok(data) => JsonResponse::success(request_id, data),
310        Err(error) => JsonResponse::error(request_id, error_code(&error), error.to_string()),
311    }
312}
313
314fn error_code(error: &CoreError) -> u32 {
315    match error {
316        CoreError::ConfigNotFound => 6001,
317        CoreError::ConfigParseError(_) => 6002,
318        CoreError::InvalidProvider(_) => 6003,
319        CoreError::IndexCorrupted(_) => 6004,
320        CoreError::RebuildFailed(_) => 6005,
321        CoreError::SocketError(_) => 6006,
322        CoreError::DispatchError(_) => 6007,
323        CoreError::ConfigReadOnly => 6008,
324        CoreError::ExportFailed(_) => 6009,
325        CoreError::ImportVersionMismatch(_) => 6010,
326        CoreError::ImportFailed(_) => 6011,
327        CoreError::InitFailed(_) => 6012,
328        CoreError::TrainerFailed(_) => 6013,
329        CoreError::TrainerTimeout => 6014,
330        CoreError::TrainerMalformedOutput(_) => 6015,
331        CoreError::ProjectDirNotFound => 6016,
332        CoreError::LegacyDatabaseDetected { .. } => 6017,
333        CoreError::MigrationSourceNotFound => 6018,
334        CoreError::MigrationFailed(_) => 6019,
335        CoreError::EmbeddingModelMismatch { .. } => 6020,
336        CoreError::Storage(_) => 1000,
337        CoreError::Hnsw(_) => 3000,
338        CoreError::Api(_) => 2000,
339        CoreError::Consolidation(_) => 5000,
340    }
341}
342
343fn save_indexes_on_shutdown(state: &Arc<ServerState>) -> Result<(), CoreError> {
344    let index_directory = resolve_index_directory(&state.database_path);
345    let indexes = state.indexes.read().unwrap();
346    crate::persistence::save_to_disk(&index_directory, &indexes)
347}
348
349fn warn_missing_api_keys(config: &Config) {
350    let has_embedding_key = config
351        .embedding
352        .api_key
353        .as_deref()
354        .is_some_and(|k| !k.is_empty());
355    let has_llm_key = config.llm.api_key.as_deref().is_some_and(|k| !k.is_empty());
356
357    if !has_embedding_key && config.embedding.provider != "deterministic" {
358        eprintln!(
359            "warning: {} embedding provider configured without api key (set ENGRAM_VOYAGE_API_KEY)",
360            config.embedding.provider
361        );
362    }
363    if !has_llm_key && config.llm.provider != "local" {
364        eprintln!(
365            "warning: {} llm provider configured without api key (set ENGRAM_OPENAI_API_KEY)",
366            config.llm.provider
367        );
368    }
369}
370
371fn expand_tilde(path: &str) -> String {
372    if let Some(rest) = path.strip_prefix("~/")
373        && let Ok(home) = std::env::var("HOME")
374    {
375        return format!("{home}/{rest}");
376    }
377    path.to_string()
378}
engram_core/server.rs

engram_core/
server.rs
