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::lock_helpers;
18use crate::protocol::{JsonRequest, JsonResponse};
19
20const PROJECT_DB_RELATIVE: &str = ".engram/engram.db";
21const PROJECT_SOCKET_RELATIVE: &str = ".engram/engram.sock";
22
23const ROUTER_DEFAULT_ALPHA: f32 = 0.1;
24const ROUTER_DEFAULT_EPSILON: f32 = 0.15;
25
26pub struct ServerState {
27    pub database: Mutex<Database>,
28    pub indexes: RwLock<IndexSet>,
29    pub embedder: Embedder,
30    pub router: Mutex<Router>,
31    pub config: Config,
32    pub database_path: String,
33    pub embedding_provider: Arc<dyn EmbeddingProvider + Send + Sync>,
34    pub text_generator: Option<Arc<dyn TextGenerator + Send + Sync>>,
35}
36
37pub async fn run(config: Config) -> Result<(), CoreError> {
38    let cwd = std::env::current_dir()
39        .map_err(|error| CoreError::SocketError(format!("cwd unavailable: {error}")))?;
40    let home = home_dir_or_error()?;
41    let project_dir = config::resolve_project_dir(&cwd, None)?;
42    // See execute_command in main.rs for why this construction has to run on
43    // the blocking pool. reqwest::blocking::ClientBuilder::build internally
44    // spins up and drops a current-thread tokio runtime; doing that on the
45    // outer multi-threaded runtime's worker panics.
46    let state = {
47        let config = config.clone();
48        let project_dir = project_dir.clone();
49        let home = home.clone();
50        tokio::task::spawn_blocking(move || initialize_state(&config, &project_dir, &home))
51            .await
52            .map_err(|error| CoreError::SocketError(error.to_string()))??
53    };
54    {
55        let database = lock_helpers::lock_db(&state);
56        let configured_model = config
57            .embedding
58            .model
59            .as_deref()
60            .unwrap_or(config::DEFAULT_EMBEDDING_MODEL);
61        crate::migrations::embedding_model_v1::check(&database, configured_model)?;
62    }
63    warn_missing_api_keys(&config);
64    let shared_state = Arc::new(state);
65    let socket_path = resolve_socket_path(&project_dir, &config)?;
66    cleanup_stale_socket(&socket_path);
67    let listener = bind_listener(&socket_path)?;
68    accept_loop(listener, shared_state).await
69}
70
71pub fn check_legacy_database(project_dir: &Path, home_dir: &Path) -> Result<(), CoreError> {
72    let project_db = project_dir.join(PROJECT_DB_RELATIVE);
73    let home_db = home_dir.join(PROJECT_DB_RELATIVE);
74    if !project_db.exists() && home_db.exists() {
75        return Err(CoreError::LegacyDatabaseDetected {
76            legacy_path: home_db.to_string_lossy().to_string(),
77            project_path: project_dir.to_string_lossy().to_string(),
78        });
79    }
80    Ok(())
81}
82
83pub(crate) fn initialize_state(
84    config: &Config,
85    project_dir: &Path,
86    home_dir: &Path,
87) -> Result<ServerState, CoreError> {
88    crate::config::validate_dedup_threshold(config.deduplication.threshold)?;
89    crate::config::validate_search_config(&config.search)?;
90    check_legacy_database(project_dir, home_dir)?;
91    let database_path = resolve_database_path(project_dir);
92    let database = Database::open(&database_path)?;
93    crate::migrations::run_pending(&database)?;
94    let embedding_provider: Arc<dyn EmbeddingProvider + Send + Sync> =
95        Arc::from(config.build_embedding_provider()?);
96    let text_generator: Option<Arc<dyn TextGenerator + Send + Sync>> =
97        match config.build_text_generator() {
98            Ok(generator) => Some(Arc::from(generator)),
99            Err(error) => {
100                eprintln!("warning: text generator unavailable, running in degraded mode: {error}");
101                None
102            }
103        };
104    let hnsw_config = config.clone();
105    let indexes = crate::persistence::load_or_rebuild(
106        &resolve_index_directory(&database_path),
107        &database,
108        || hnsw_config.build_hnsw_params(),
109    )?;
110    let embedder = Embedder::new(config.embedding.hyde_threshold);
111    let router = Router::new(ROUTER_DEFAULT_ALPHA, ROUTER_DEFAULT_EPSILON);
112    Ok(ServerState {
113        database: Mutex::new(database),
114        indexes: RwLock::new(indexes),
115        embedder,
116        router: Mutex::new(router),
117        config: config.clone(),
118        database_path,
119        embedding_provider,
120        text_generator,
121    })
122}
123
124fn resolve_database_path(project_dir: &Path) -> String {
125    if let Ok(value) = std::env::var("ENGRAM_DB_PATH") {
126        return value;
127    }
128    project_dir
129        .join(PROJECT_DB_RELATIVE)
130        .to_string_lossy()
131        .to_string()
132}
133
134fn resolve_socket_path(project_dir: &Path, config: &Config) -> Result<String, CoreError> {
135    if let Ok(value) = std::env::var("ENGRAM_SOCKET_PATH") {
136        return Ok(value);
137    }
138    // Prefer project socket when the `.engram/` dir exists (walk-up already validated this).
139    if project_dir.join(".engram").is_dir() {
140        return Ok(project_dir
141            .join(PROJECT_SOCKET_RELATIVE)
142            .to_string_lossy()
143            .to_string());
144    }
145    match config.server.socket_path.as_deref() {
146        Some(fallback) => Ok(expand_tilde(fallback)),
147        None => Err(CoreError::SocketError(
148            "no socket path available: no project .engram/ marker found, \
149             ENGRAM_SOCKET_PATH not set, and server.socket_path not configured"
150                .into(),
151        )),
152    }
153}
154
155fn home_dir_or_error() -> Result<PathBuf, CoreError> {
156    match std::env::var("HOME") {
157        Ok(value) if !value.is_empty() => Ok(PathBuf::from(value)),
158        _ => Err(CoreError::InitFailed(
159            "HOME environment variable not set".into(),
160        )),
161    }
162}
163
164pub(crate) fn resolve_index_directory(database_path: &str) -> String {
165    std::path::Path::new(database_path)
166        .parent()
167        .map(|parent| parent.to_string_lossy().to_string())
168        .unwrap_or_else(|| ".".to_string())
169}
170
171fn cleanup_stale_socket(socket_path: &str) {
172    let _ = std::fs::remove_file(socket_path);
173}
174
175fn bind_listener(socket_path: &str) -> Result<UnixListener, CoreError> {
176    if let Some(parent) = std::path::Path::new(socket_path).parent() {
177        std::fs::create_dir_all(parent)
178            .map_err(|error| CoreError::SocketError(error.to_string()))?;
179    }
180    UnixListener::bind(socket_path).map_err(|error| CoreError::SocketError(error.to_string()))
181}
182
183async fn accept_loop(listener: UnixListener, state: Arc<ServerState>) -> Result<(), CoreError> {
184    let mut sigterm =
185        signal(SignalKind::terminate()).map_err(|e| CoreError::SocketError(e.to_string()))?;
186    spawn_background_reindex(Arc::clone(&state));
187    loop {
188        tokio::select! {
189            accept_result = listener.accept() => {
190                let (stream, _address) = accept_result
191                    .map_err(|error| CoreError::SocketError(error.to_string()))?;
192                let client_state = Arc::clone(&state);
193                tokio::spawn(async move {
194                    if let Err(error) = handle_client(stream, client_state).await {
195                        eprintln!("client error: {error}");
196                    }
197                });
198            }
199            _ = sigterm.recv() => {
200                return save_indexes_on_shutdown(&state);
201            }
202        }
203    }
204}
205
206fn spawn_background_reindex(state: Arc<ServerState>) {
207    let interval_secs = state.config.server.reindex_interval_secs;
208    if interval_secs == 0 {
209        return;
210    }
211    tokio::spawn(async move {
212        let mut interval = tokio::time::interval(std::time::Duration::from_secs(interval_secs));
213        interval.tick().await; // skip first immediate tick
214        loop {
215            interval.tick().await;
216            let reindex_state = Arc::clone(&state);
217            let _ = tokio::task::spawn_blocking(move || {
218                reindex_unindexed_memories(&reindex_state);
219            })
220            .await;
221        }
222    });
223}
224
225/// Reindex unindexed memories from SQLite into the HNSW index.
226///
227/// **Unstable:** exposed for latency benchmarking only
228/// (`crates/engram-core/tests/search_latency_bench.rs`). Not part of the public
229/// API contract; may change or be removed without notice.
230#[doc(hidden)]
231pub fn reindex_unindexed_memories(state: &ServerState) {
232    let database = lock_helpers::lock_db(state);
233    let unindexed = match query_unindexed_ids(&database) {
234        Ok(ids) => ids,
235        Err(_) => return,
236    };
237    if unindexed.is_empty() {
238        return;
239    }
240    let mut indexes = lock_helpers::write_indexes(state);
241    for memory_id in &unindexed {
242        let _ = reindex_single_memory(&database, &mut indexes, memory_id);
243    }
244}
245
246fn query_unindexed_ids(database: &Database) -> Result<Vec<String>, CoreError> {
247    let mut statement = database
248        .connection()
249        .prepare(
250            "SELECT id FROM memories WHERE indexed = 0 \
251             AND embedding_context IS NOT NULL LIMIT 100",
252        )
253        .map_err(|e| CoreError::Storage(engram_storage::StorageError::from(e)))?;
254    let rows = statement
255        .query_map([], |row| row.get::<_, String>(0))
256        .map_err(|e| CoreError::Storage(engram_storage::StorageError::from(e)))?;
257    let ids: Vec<String> = rows.flatten().collect();
258    Ok(ids)
259}
260
261fn reindex_single_memory(
262    database: &Database,
263    indexes: &mut IndexSet,
264    memory_id: &str,
265) -> Result<(), CoreError> {
266    let memory = database.get_memory(memory_id)?;
267    let embedding = crate::persistence::extract_embeddings_from_memory(&memory)?;
268    let id_hash = crate::persistence::hash_string_to_u64(memory_id);
269    let rng_value = crate::persistence::deterministic_rng(id_hash);
270    if !indexes.contains(id_hash) {
271        indexes.insert_atomic(id_hash, memory_id, &embedding, rng_value)?;
272    }
273    database.set_memory_indexed(memory_id, true)?;
274    Ok(())
275}
276
277async fn handle_client(
278    stream: tokio::net::UnixStream,
279    state: Arc<ServerState>,
280) -> Result<(), CoreError> {
281    let (reader, mut writer) = stream.into_split();
282    let mut lines = BufReader::new(reader).lines();
283    while let Some(line) = lines
284        .next_line()
285        .await
286        .map_err(|error| CoreError::SocketError(error.to_string()))?
287    {
288        let response = process_request_line(&line, &state).await;
289        let serialized = serde_json::to_string(&response)
290            .map_err(|error| CoreError::SocketError(error.to_string()))?;
291        writer
292            .write_all(serialized.as_bytes())
293            .await
294            .map_err(|error| CoreError::SocketError(error.to_string()))?;
295        writer
296            .write_all(b"\n")
297            .await
298            .map_err(|error| CoreError::SocketError(error.to_string()))?;
299    }
300    Ok(())
301}
302
303async fn process_request_line(line: &str, state: &Arc<ServerState>) -> JsonResponse {
304    let request: JsonRequest = match serde_json::from_str(line) {
305        Ok(parsed) => parsed,
306        Err(error) => {
307            return JsonResponse::error(String::new(), 4000, format!("invalid json: {error}"));
308        }
309    };
310    let request_id = request.id.clone();
311    match dispatch::route(&request.method, state, request.params).await {
312        Ok(data) => JsonResponse::success(request_id, data),
313        Err(error) => JsonResponse::error(request_id, error_code(&error), error.to_string()),
314    }
315}
316
317fn error_code(error: &CoreError) -> u32 {
318    match error {
319        CoreError::ConfigNotFound => 6001,
320        CoreError::ConfigParseError(_) => 6002,
321        CoreError::InvalidProvider(_) => 6003,
322        CoreError::IndexCorrupted(_) => 6004,
323        CoreError::RebuildFailed(_) => 6005,
324        CoreError::SocketError(_) => 6006,
325        CoreError::DispatchError(_) => 6007,
326        CoreError::ConfigReadOnly => 6008,
327        CoreError::ExportFailed(_) => 6009,
328        CoreError::ImportVersionMismatch(_) => 6010,
329        CoreError::ImportFailed(_) => 6011,
330        CoreError::InitFailed(_) => 6012,
331        CoreError::TrainerFailed(_) => 6013,
332        CoreError::TrainerTimeout => 6014,
333        CoreError::TrainerMalformedOutput(_) => 6015,
334        CoreError::ProjectDirNotFound => 6016,
335        CoreError::LegacyDatabaseDetected { .. } => 6017,
336        CoreError::MigrationSourceNotFound => 6018,
337        CoreError::MigrationFailed(_) => 6019,
338        CoreError::EmbeddingModelMismatch { .. } => 6020,
339        CoreError::IndexHashCollision { .. } => 6021,
340        CoreError::ConfigValidation(_) => 6022,
341        CoreError::Storage(_) => 1000,
342        CoreError::Hnsw(_) => 3000,
343        CoreError::Api(_) => 2000,
344        CoreError::Consolidation(_) => 5000,
345    }
346}
347
348fn save_indexes_on_shutdown(state: &Arc<ServerState>) -> Result<(), CoreError> {
349    let index_directory = resolve_index_directory(&state.database_path);
350    let indexes = lock_helpers::read_indexes(state);
351    crate::persistence::save_to_disk(&index_directory, &indexes)
352}
353
354fn warn_missing_api_keys(config: &Config) {
355    let has_embedding_key = config
356        .embedding
357        .api_key
358        .as_deref()
359        .is_some_and(|k| !k.is_empty());
360    let has_llm_key = config.llm.api_key.as_deref().is_some_and(|k| !k.is_empty());
361
362    if !has_embedding_key && config.embedding.provider != "deterministic" {
363        eprintln!(
364            "warning: {} embedding provider configured without api key (set ENGRAM_VOYAGE_API_KEY)",
365            config.embedding.provider
366        );
367    }
368    if !has_llm_key && config.llm.provider != "local" {
369        eprintln!(
370            "warning: {} llm provider configured without api key (set ENGRAM_OPENAI_API_KEY)",
371            config.llm.provider
372        );
373    }
374}
375
376fn expand_tilde(path: &str) -> String {
377    if let Some(rest) = path.strip_prefix("~/")
378        && let Ok(home) = std::env::var("HOME")
379    {
380        return format!("{home}/{rest}");
381    }
382    path.to_string()
383}
engram_core/server.rs

engram_core/
server.rs
