weftgraph 0.1.0

//! Composition root: probes the server, selects the store and engine
//! implementations, and publishes the in-process client.

use std::sync::{Arc, OnceLock};

use async_trait::async_trait;
use authz_resolver_sdk::pep::PolicyEnforcer;
use toolkit::api::OpenApiRegistry;
use toolkit::{
    DatabaseCapability, Gear, GearCtx, Healthcheck, HealthcheckResult, RestApiCapability,
};
use tracing::{debug, error, info, warn};

use graph_storage_sdk::GraphStorageClientV1;
use graph_storage_sdk::plugin_api::EmbeddingProviderV1;

use crate::api::rest::routes;
use crate::config::{EmbeddingProviderKind, GraphStorageConfig};
use crate::domain::embedding::SpaceState;
use crate::domain::local_client::GraphStorageLocalClient;
use crate::domain::service::GraphServices;
use crate::infra::embedding::fake::FakeEmbeddingProvider;
use crate::infra::engine::PgGraphEngine;
use crate::infra::store::{PgGraphStore, spaces};

/// The graph-storage gear.
#[toolkit::gear(name = "graph-storage", deps = [authz_resolver], capabilities = [db, rest])]
pub struct GraphStorage {
    services: OnceLock<Arc<GraphServices>>,
}

impl Default for GraphStorage {
    fn default() -> Self {
        Self {
            services: OnceLock::new(),
        }
    }
}

#[async_trait]
impl Gear for GraphStorage {
    async fn init(&self, ctx: &GearCtx) -> anyhow::Result<()> {
        let cfg = ctx.config_or_default::<GraphStorageConfig>()?.validated()?;
        debug!(
            traversal_hop = ?cfg.traversal_hop,
            ingest_max_nodes = cfg.ingest_max_nodes,
            "loaded graph-storage configuration"
        );

        // The configured vector width must be the width the schema was
        // migrated with, or every stored vector is incomparable with every
        // query vector.
        let migrated = crate::infra::store::ingest::migrated_embedding_dimension();
        if cfg.embedding_dimension != migrated {
            anyhow::bail!(
                "graph-storage.embedding_dimension is {} but the schema was migrated with {migrated}; \
                 vector search would compare incomparable vectors",
                cfg.embedding_dimension
            );
        }

        // Acquiring the database capability is what makes the platform run
        // this gear's migrations before the REST phase; declaring `db` alone
        // is silently insufficient.
        let db_raw = ctx.db_required()?;
        let db = Arc::new(db_raw.db());

        // SQL/PGQ is a probed backend capability, not a gear requirement:
        // the property-graph migration is skipped on an older server, and the
        // engine then serves every hop on the fallback backend.
        let pgq_available = crate::infra::engine::probe_pgq(&db).await;
        if !pgq_available {
            match cfg.traversal_hop {
                crate::config::HopStrategy::Auto => warn!(
                    "this server does not provide SQL/PGQ; traversal will use the two-query hop"
                ),
                crate::config::HopStrategy::Pgq => error!(
                    "traversal_hop is `pgq` and this server does not provide SQL/PGQ; the gear \
                     reports not ready and refuses traversal rather than substitute another \
                     backend"
                ),
                crate::config::HopStrategy::TwoQuery => {}
            }
        }

        let store = Arc::new(PgGraphStore::new(
            Arc::clone(&db),
            cfg.clone(),
            pgq_available,
        ));
        let engine = Arc::new(PgGraphEngine::new(Arc::clone(&store)));
        let enforcer = PolicyEnforcer::new(ctx.client_hub().get()?);

        let provider = select_embedding_provider(&cfg).await?;
        let embedding = resolve_embedding_space(&db, provider, &cfg).await?;

        let services = Arc::new(GraphServices::new(cfg, store, engine, enforcer, embedding));
        self.services
            .set(Arc::clone(&services))
            .map_err(|_| anyhow::anyhow!("{} gear already initialized", Self::MODULE_NAME))?;

        ctx.client_hub()
            .register::<dyn GraphStorageClientV1>(Arc::new(GraphStorageLocalClient::new(services)));

        info!(pgq_available, "graph-storage gear initialized");
        Ok(())
    }
}

/// Pick the deployment's one embedding provider.
///
/// One per deployment, per the single-embedding-space constraint. A
/// misconfigured choice fails the boot rather than falling back: silently
/// substituting the fake would fill the graph with vectors that rank nothing
/// meaningfully, and the deployment would look healthy the whole time.
///
/// # Errors
///
/// No provider configured at all; an `onnx` deployment whose artifacts are
/// missing or unloadable, or one built without the `onnx` feature.
async fn select_embedding_provider(
    cfg: &GraphStorageConfig,
) -> anyhow::Result<Arc<dyn EmbeddingProviderV1>> {
    let Some(kind) = cfg.embedding_provider else {
        anyhow::bail!(
            "graph-storage.embedding_provider is not set; name one of `fake`, `onnx` or \
             `remote` -- the gear does not fall back to the fake, whose vectors rank nothing \
             meaningfully"
        );
    };
    match kind {
        EmbeddingProviderKind::Fake => {
            warn!(
                "graph-storage.embedding_provider is `fake`: vector search will answer, \
                 but its ranking carries no semantics"
            );
            Ok(Arc::new(FakeEmbeddingProvider::new(
                cfg.embedding_dimension,
            )))
        }
        EmbeddingProviderKind::Onnx => onnx_provider(cfg).await,
        EmbeddingProviderKind::Remote => remote_provider(cfg),
    }
}

#[cfg(feature = "remote")]
fn remote_provider(cfg: &GraphStorageConfig) -> anyhow::Result<Arc<dyn EmbeddingProviderV1>> {
    let named = |key: &str, value: &Option<String>| -> anyhow::Result<String> {
        value.clone().ok_or_else(|| {
            anyhow::anyhow!("graph-storage.{key} is required by the `remote` embedding provider")
        })
    };
    let mut config = remote_embedding_plugin::RemoteProviderConfig::new(
        named("embedding_remote_base_url", &cfg.embedding_remote_base_url)?,
        named("embedding_remote_model", &cfg.embedding_remote_model)?,
    );
    config.dimension = cfg.embedding_dimension;
    config.request_dimensions = cfg.embedding_remote_request_dimensions;
    config.batch_size = cfg.embedding_remote_batch_size as usize;
    config.timeout = std::time::Duration::from_secs(cfg.embedding_remote_timeout_secs);

    // The credential is named, not carried: the config file (and its dump)
    // holds the variable's name, the process environment holds the value.
    if let Some(variable) = &cfg.embedding_remote_api_key_env {
        let value = std::env::var(variable).map_err(|_| {
            anyhow::anyhow!(
                "graph-storage.embedding_remote_api_key_env names {variable}, which is not set \
                 in this process's environment"
            )
        })?;
        if value.trim().is_empty() {
            anyhow::bail!(
                "graph-storage.embedding_remote_api_key_env names {variable}, which is empty"
            );
        }
        config = config.with_api_key(value);
    }

    let provider = remote_embedding_plugin::RemoteEmbeddingProvider::new(config)?;
    info!(
        endpoint = %provider.endpoint(),
        model = %provider.embedding_space().model_artifact,
        "configured the remote embedding provider"
    );
    Ok(Arc::new(provider))
}

#[cfg(not(feature = "remote"))]
fn remote_provider(_cfg: &GraphStorageConfig) -> anyhow::Result<Arc<dyn EmbeddingProviderV1>> {
    anyhow::bail!(
        "graph-storage.embedding_provider is `remote` but this binary was built without the \
         `remote` feature; rebuild with it or choose another provider"
    )
}

#[cfg(feature = "onnx")]
async fn onnx_provider(cfg: &GraphStorageConfig) -> anyhow::Result<Arc<dyn EmbeddingProviderV1>> {
    let named = |key: &str, value: &Option<String>| -> anyhow::Result<String> {
        value.clone().ok_or_else(|| {
            anyhow::anyhow!("graph-storage.{key} is required by the `onnx` embedding provider")
        })
    };
    let mut config = onnx_embedding_plugin::OnnxProviderConfig::new(
        named("embedding_model_path", &cfg.embedding_model_path)?,
        named("embedding_tokenizer_path", &cfg.embedding_tokenizer_path)?,
    );
    config.dimension = cfg.embedding_dimension;

    // A `RuntimeHung` here has leaked a thread that cannot be joined, so the
    // process must end rather than retry. Returning the error does that: the
    // platform aborts the boot.
    let provider = onnx_embedding_plugin::OnnxEmbeddingProvider::load(config).await?;
    info!(
        model = %provider.embedding_space().model_artifact,
        "loaded the in-process ONNX embedding provider"
    );
    Ok(Arc::new(provider))
}

#[cfg(not(feature = "onnx"))]
#[expect(
    clippy::unused_async,
    reason = "one signature for both builds; the feature-enabled arm is async"
)]
async fn onnx_provider(_cfg: &GraphStorageConfig) -> anyhow::Result<Arc<dyn EmbeddingProviderV1>> {
    anyhow::bail!(
        "graph-storage.embedding_provider is `onnx` but this binary was built without the \
         `onnx` feature; rebuild with it or choose another provider"
    )
}

/// Reconcile the provider against the space the stored vectors belong to.
///
/// A mismatch does not stop the gear: only the vector arm is incomparable, and
/// every other path serves the same rows it always did. It stops *that arm*,
/// loudly, which is what `fr-embedding-dim-guard` asks for — the readiness
/// surface that should also report it does not exist yet (a known gap of this iteration).
async fn resolve_embedding_space(
    db: &toolkit_db::secure::Db,
    provider: Arc<dyn EmbeddingProviderV1>,
    cfg: &GraphStorageConfig,
) -> anyhow::Result<crate::domain::embedding::EmbeddingCoordinator> {
    // The provider's own width against the migrated column, before anything
    // is written: a provider of the wrong width cannot produce one storable
    // vector, so this is a configuration error rather than a runtime one.
    if provider.dimension() != cfg.embedding_dimension {
        anyhow::bail!(
            "the embedding provider declares {} dimensions but \
             graph-storage.embedding_dimension is {}",
            provider.dimension(),
            cfg.embedding_dimension
        );
    }

    let state = match spaces::resolve(db, provider.embedding_space()).await? {
        spaces::SpaceResolution::Active { epoch } => {
            info!(
                epoch,
                identity = %provider.embedding_space().identity_hash,
                model = %provider.embedding_space().model_artifact,
                "embedding space active"
            );
            SpaceState::Active { epoch }
        }
        spaces::SpaceResolution::Mismatched {
            recorded_identity,
            recorded_epoch,
        } => {
            error!(
                recorded_epoch,
                recorded_identity = %recorded_identity,
                active_identity = %provider.embedding_space().identity_hash,
                "stored vectors belong to a different embedding space than the configured \
                 provider; vector search is blocked until the graph is re-embedded"
            );
            SpaceState::Blocked
        }
    };

    Ok(crate::domain::embedding::EmbeddingCoordinator::new(
        provider,
        state,
        cfg.embedding_input_max_bytes,
    ))
}

impl DatabaseCapability for GraphStorage {
    fn migrations(&self) -> Vec<Box<dyn sea_orm_migration::MigrationTrait>> {
        use sea_orm_migration::MigratorTrait;
        crate::infra::storage::migrations::Migrator::migrations()
    }
}

impl RestApiCapability for GraphStorage {
    fn register_rest(
        &self,
        _ctx: &GearCtx,
        router: axum::Router,
        openapi: &dyn OpenApiRegistry,
    ) -> anyhow::Result<axum::Router> {
        let services = self
            .services
            .get()
            .ok_or_else(|| anyhow::anyhow!("graph-storage services are not initialized"))?
            .clone();
        Ok(routes::register_routes(router, openapi, services))
    }

    /// Readiness through the platform's own `/readyz` and `/health`, which
    /// the gateway can serve on a listener of its own, apart from the API.
    /// One composite check, as the platform asks: the gear's aggregate, not
    /// its rows. The per-component detail stays on the gear's route.
    fn healthcheck(&self, _ctx: &GearCtx) -> Option<Arc<dyn Healthcheck>> {
        let services = self.services.get()?.clone();
        Some(Arc::new(PlatformReadiness { services }))
    }
}

struct PlatformReadiness {
    services: Arc<GraphServices>,
}

#[async_trait]
impl Healthcheck for PlatformReadiness {
    fn name(&self) -> &'static str {
        "graph-storage"
    }

    async fn check(&self) -> HealthcheckResult {
        platform_result(&self.services.readiness().await)
    }
}

/// The gear's readiness as the platform reads it.
///
/// Not ready is `unhealthy`: the pod leaves rotation. Ready with any row
/// degraded or unhealthy -- a space mismatch, an unavailable provider, a
/// preferred backend absent -- is `degraded`, which keeps it in rotation:
/// the platform asks that a dependency the gear can serve around not evict
/// every pod. A capability this build does not ship is not a fault. The
/// message names components only, never a row's text, because `/health` is
/// unauthenticated.
fn platform_result(readiness: &graph_storage_sdk::models::Readiness) -> HealthcheckResult {
    use graph_storage_sdk::models::ReadinessState;

    let named = |fatal: bool| {
        readiness
            .components
            .iter()
            .filter(|row| {
                if fatal {
                    row.fatal()
                } else {
                    matches!(
                        row.state,
                        ReadinessState::Degraded | ReadinessState::Unhealthy
                    )
                }
            })
            .map(|row| row.component.as_str())
            .collect::<Vec<_>>()
            .join(", ")
    };
    if !readiness.ready {
        return HealthcheckResult::unhealthy(format!("not ready: {}", named(true)))
            .with_code("graph_storage.not_ready");
    }
    let degraded = named(false);
    if degraded.is_empty() {
        HealthcheckResult::healthy()
    } else {
        HealthcheckResult::degraded(format!("degraded: {degraded}"))
            .with_code("graph_storage.degraded")
    }
}

#[cfg(test)]
mod platform_readiness_tests {
    use graph_storage_sdk::models::{
        ComponentReadiness, DATABASE, DYNAMIC_INDEXES, EMBEDDING_SPACE, Readiness, ReadinessState,
    };
    use toolkit::HealthcheckStatus;

    use super::platform_result;

    fn row(component: &str, state: ReadinessState) -> ComponentReadiness {
        ComponentReadiness::new(
            component,
            state,
            "a problem text the platform must not see",
            "what it blocks",
            "recovery",
        )
    }

    #[test]
    fn all_healthy_is_healthy_and_a_missing_capability_is_not_a_fault() {
        let result = platform_result(&Readiness::of(vec![
            ComponentReadiness::healthy(DATABASE),
            row(DYNAMIC_INDEXES, ReadinessState::NotImplemented),
        ]));
        assert_eq!(result.status, HealthcheckStatus::Healthy, "{result:?}");
        assert_eq!(result.code, None);
    }

    /// The row the matrix keeps ready while unhealthy stays in rotation.
    #[test]
    fn a_space_mismatch_degrades_and_names_only_the_component() {
        let result = platform_result(&Readiness::of(vec![
            ComponentReadiness::healthy(DATABASE),
            row(EMBEDDING_SPACE, ReadinessState::Unhealthy),
        ]));
        assert_eq!(result.status, HealthcheckStatus::Degraded, "{result:?}");
        assert_eq!(result.code.as_deref(), Some("graph_storage.degraded"));
        let message = result.message.unwrap_or_default();
        assert!(message.contains(EMBEDDING_SPACE), "{message}");
        assert!(!message.contains("problem text"), "{message}");
    }

    #[test]
    fn not_ready_is_unhealthy_and_names_what_blocks_it() {
        let result = platform_result(&Readiness::of(vec![
            row(DATABASE, ReadinessState::Unhealthy),
            row(EMBEDDING_SPACE, ReadinessState::Unhealthy),
        ]));
        assert_eq!(result.status, HealthcheckStatus::Unhealthy, "{result:?}");
        assert_eq!(result.code.as_deref(), Some("graph_storage.not_ready"));
        assert_eq!(result.message, Some(format!("not ready: {DATABASE}")));
    }
}

#[cfg(test)]
mod tests {
    //! The boot-time path an operator depends on to get the provider they
    //! configured: the plugins' own suites construct their providers
    //! directly, so without these nothing ever ran `select_embedding_provider`
    //! or either feature arm behind it.

    use super::{EmbeddingProviderKind, GraphStorageConfig, select_embedding_provider};

    fn with(kind: Option<EmbeddingProviderKind>) -> GraphStorageConfig {
        GraphStorageConfig {
            embedding_provider: kind,
            ..GraphStorageConfig::default()
        }
    }

    /// Unset is refused rather than quietly served by the fake, whose
    /// vectors rank nothing -- and the refusal names what to set.
    #[tokio::test]
    async fn an_unset_provider_is_refused_and_says_what_to_set() {
        let refused = select_embedding_provider(&with(None))
            .await
            .err()
            .expect("no provider is not a default");
        let message = refused.to_string();
        for named in ["embedding_provider", "fake", "onnx", "remote"] {
            assert!(message.contains(named), "{named} is named: {message}");
        }
    }

    #[tokio::test]
    async fn the_fake_is_wired_at_the_configured_dimension() {
        let config = GraphStorageConfig {
            embedding_dimension: 16,
            ..with(Some(EmbeddingProviderKind::Fake))
        };
        let provider = select_embedding_provider(&config)
            .await
            .expect("the fake needs nothing");
        assert_eq!(provider.embedding_space().dimension, 16);
    }

    /// Built with `remote`: the configuration becomes a remote provider,
    /// and each key it cannot do without is refused by name.
    #[cfg(feature = "remote")]
    #[tokio::test]
    async fn remote_is_wired_from_the_configuration() {
        let configured = GraphStorageConfig {
            // Loopback, so no credential rule applies and nothing is sent:
            // constructing the provider validates, it does not call out.
            embedding_dimension: 32,
            embedding_remote_base_url: Some("http://127.0.0.1:9/v1".to_owned()),
            embedding_remote_model: Some("wired-model".to_owned()),
            ..with(Some(EmbeddingProviderKind::Remote))
        };
        let provider = select_embedding_provider(&configured)
            .await
            .expect("a complete remote configuration boots");
        // The remote identity is the model *at* its endpoint -- the same model
        // name behind two endpoints is two spaces -- so this one comparison
        // proves both configured values reached the provider.
        assert_eq!(
            provider.embedding_space().model_artifact,
            "wired-model@http://127.0.0.1:9/v1/embeddings"
        );
        assert_eq!(provider.embedding_space().dimension, 32);

        for (missing, key) in [
            (
                GraphStorageConfig {
                    embedding_remote_base_url: None,
                    ..configured.clone()
                },
                "embedding_remote_base_url",
            ),
            (
                GraphStorageConfig {
                    embedding_remote_model: None,
                    ..configured.clone()
                },
                "embedding_remote_model",
            ),
        ] {
            let refused = select_embedding_provider(&missing)
                .await
                .err()
                .expect("a required key is required");
            assert!(refused.to_string().contains(key), "{key}: {refused}");
        }

        // A credential variable that names nothing in this environment is a
        // boot failure, not a provider that fails every request later.
        let unset = GraphStorageConfig {
            embedding_remote_api_key_env: Some(
                "GRAPH_STORAGE_TEST_CREDENTIAL_THAT_IS_NEVER_SET".to_owned(),
            ),
            ..configured
        };
        let refused = select_embedding_provider(&unset)
            .await
            .err()
            .expect("an unset credential variable stops the boot");
        assert!(
            refused.to_string().contains("not set"),
            "the refusal says why: {refused}"
        );
    }

    /// Built without `remote`, asking for it is a clear refusal rather than
    /// a silent substitution.
    #[cfg(not(feature = "remote"))]
    #[tokio::test]
    async fn remote_without_the_feature_says_so() {
        let refused = select_embedding_provider(&with(Some(EmbeddingProviderKind::Remote)))
            .await
            .err()
            .expect("a provider the binary lacks is refused");
        assert!(
            refused.to_string().contains("`remote` feature"),
            "{refused}"
        );
    }

    /// Built with `onnx`: a missing artifact is refused by name before
    /// anything is loaded. Loading real artifacts is the ONNX lane's case
    /// below, since only that lane has them.
    #[cfg(feature = "onnx")]
    #[tokio::test]
    async fn onnx_names_the_artifact_it_is_missing() {
        let refused = select_embedding_provider(&with(Some(EmbeddingProviderKind::Onnx)))
            .await
            .err()
            .expect("no artifacts, no provider");
        assert!(
            refused.to_string().contains("embedding_model_path"),
            "{refused}"
        );
    }

    /// With the artifacts the ONNX lane downloads, the configured provider
    /// is the one that loads. Skipped where they are absent, unless the
    /// lane requires it -- a green run that quietly skipped would prove
    /// nothing about the wiring.
    #[cfg(feature = "onnx")]
    #[tokio::test]
    async fn onnx_is_wired_from_the_configuration() {
        let (Ok(model), Ok(tokenizer)) = (
            std::env::var("GRAPH_STORAGE_ONNX_MODEL"),
            std::env::var("GRAPH_STORAGE_ONNX_TOKENIZER"),
        ) else {
            assert!(
                std::env::var("GRAPH_STORAGE_ONNX_REQUIRED").is_err(),
                "GRAPH_STORAGE_ONNX_REQUIRED is set but the model artifacts are not"
            );
            eprintln!("no ONNX artifacts in this environment - skipping");
            return;
        };
        let configured = GraphStorageConfig {
            embedding_model_path: Some(model),
            embedding_tokenizer_path: Some(tokenizer),
            ..with(Some(EmbeddingProviderKind::Onnx))
        };
        let provider = select_embedding_provider(&configured)
            .await
            .expect("the downloaded artifacts load");
        assert_eq!(
            provider.embedding_space().dimension,
            configured.embedding_dimension
        );
    }

    #[cfg(not(feature = "onnx"))]
    #[tokio::test]
    async fn onnx_without_the_feature_says_so() {
        let refused = select_embedding_provider(&with(Some(EmbeddingProviderKind::Onnx)))
            .await
            .err()
            .expect("a provider the binary lacks is refused");
        assert!(refused.to_string().contains("`onnx` feature"), "{refused}");
    }
}