slightly improved http error status codes and db health check (#154)

* use 500 instead of 401 on connect errors

* set max connections at 100

* add simple db connection check

kepler-core/src/db.rs

@@ -142,6 +142,17 @@ where
     }
 }
 
+impl<C, B, K> OrbitDatabase<C, B, K>
+where
+    C: TransactionTrait,
+{
+    pub async fn check_db_connection(&self) -> Result<(), DbErr> {
+        // there's a `ping` method on the connection, but we can't access it from here
+        // but starting a transaction should be enough to check the connection
+        self.conn.begin().await.map(|_| ())
+    }
+}
+
 pub type InvocationInputs<W> = HashMap<(OrbitId, String), (Metadata, HashBuffer<W>)>;
 
 impl<C, B, K> OrbitDatabase<C, B, K>

src/lib.rs

@@ -22,7 +22,7 @@ mod tracing;
 use config::{BlockStorage, Config, Keys, StagingStorage};
 use kepler_core::{
     keys::{SecretsSetup, StaticSecret},
-    sea_orm::{Database, DatabaseConnection},
+    sea_orm::{ConnectOptions, Database, DatabaseConnection},
     storage::{either::Either, memory::MemoryStaging, StorageConfig},
     OrbitDatabase,
 };
@@ -86,8 +86,11 @@ pub async fn app(config: &Figment) -> Result<Rocket<Build>> {
         Keys::Static(s) => s.try_into()?,
     };
 
+    let mut connect_opts = ConnectOptions::from(&kepler_config.storage.database);
+    connect_opts.max_connections(100);
+
     let kepler = Kepler::new(
-        Database::connect(&kepler_config.storage.database).await?,
+        Database::connect(connect_opts).await?,
         kepler_config.storage.blocks.open().await?,
         key_setup.setup(()).await?,
     )

src/routes/mod.rs

@@ -12,22 +12,31 @@ use crate::{
     BlockStage, BlockStores, Kepler,
 };
 use kepler_core::{
+    sea_orm::DbErr,
     storage::{ImmutableReadStore, ImmutableStaging},
     types::Resource,
     util::{DelegationInfo, InvocationInfo},
-    TxError,
+    TxError, TxStoreError,
 };
 
 pub mod util;
 use util::LimitedReader;
 
 #[allow(clippy::let_unit_value)]
 pub mod util_routes {
+    use super::*;
+
     #[options("/<_s..>")]
     pub async fn cors(_s: std::path::PathBuf) {}
 
     #[get("/healthz")]
-    pub fn healthcheck() {}
+    pub async fn healthcheck(s: &State<Kepler>) -> Status {
+        if s.check_db_connection().await.is_ok() {
+            Status::Ok
+        } else {
+            Status::InternalServerError
+        }
+    }
 }
 
 #[get("/peer/generate/<orbit>")]
@@ -69,6 +78,7 @@ pub async fn delegate(
                 (
                     match e {
                         TxError::OrbitNotFound => Status::NotFound,
+                        TxError::Db(DbErr::ConnectionAcquire) => Status::InternalServerError,
                         _ => Status::Unauthorized,
                     },
                     e.to_string(),
@@ -183,7 +193,18 @@ pub async fn invoke(
                     _ => unreachable!(),
                 },
             )
-            .map_err(|e| (Status::Unauthorized, e.to_string()));
+            .map_err(|e| {
+                (
+                    match e {
+                        TxStoreError::Tx(TxError::OrbitNotFound) => Status::NotFound,
+                        TxStoreError::Tx(TxError::Db(DbErr::ConnectionAcquire)) => {
+                            Status::InternalServerError
+                        }
+                        _ => Status::Unauthorized,
+                    },
+                    e.to_string(),
+                )
+            });
 
         timer.observe_duration();
         res