Add basic resolvers for session and sessions

Cargo.toml

@@ -4,4 +4,7 @@ members = ["models", "sessions"]
 resolver = "2"
 
 [workspace.dependencies]
-sea-orm = { version = "0.12.14", features = ["sqlx-mysql"] }
+sea-orm = { version = "0.12.14", features = [
+    "runtime-tokio-rustls",
+    "sqlx-mysql",
+] }

sessions/Cargo.toml

@@ -6,11 +6,13 @@ edition = "2021"
 [dependencies]
 anyhow = "1.0.81"
 async-graphql = { version = "7.0.2", default-features = false, features = [
+    "chrono",
     "graphiql",
     "tracing",
 ] }
 async-graphql-axum = { version = "7.0.2" }
 axum = { version = "0.7.4", features = ["ws"] }
+chrono = { version = "0.4.35" }
 clap = { version = "4.5.2", features = ["derive", "env"] }
 dotenvy = { version = "0.15.7" }
 models = { path = "../models" }

sessions/src/graphql.rs

@@ -1,4 +1,9 @@
-use async_graphql::{EmptyMutation, EmptySubscription, MergedObject, Schema, SchemaBuilder};
+use async_graphql::{
+    Context, EmptyMutation, EmptySubscription, Object, Schema, SchemaBuilder, SimpleObject,
+};
+use chrono::{DateTime, Utc};
+use models::bl_session;
+use sea_orm::{DatabaseConnection, EntityTrait};
 
 /// The GraphQL schema exposed by the service
 pub type RootSchema = Schema<RootQuery, EmptyMutation, EmptySubscription>;
@@ -8,8 +13,57 @@ pub fn root_schema_builder() -> SchemaBuilder<RootQuery, EmptyMutation, EmptySub
     Schema::build(RootQuery, EmptyMutation, EmptySubscription)
 }
 
+/// A Beamline Session
+#[derive(Debug, SimpleObject)]
+struct Session {
+    /// An opaque unique identifier for the session
+    session_id: u32,
+    /// The number of session within the Proposal
+    visit_number: Option<u32>,
+    /// The date and time at which the Session began
+    start: Option<DateTime<Utc>>,
+    /// The date and time at which the Session ended
+    end: Option<DateTime<Utc>>,
+}
+
+impl From<bl_session::Model> for Session {
+    fn from(value: bl_session::Model) -> Self {
+        Self {
+            session_id: value.session_id,
+            visit_number: value.visit_number,
+            start: value.start_date.map(|date| date.and_utc()),
+            end: value.end_date.map(|date| date.and_utc()),
+        }
+    }
+}
+
 /// The root query of the service
-#[derive(Debug, Clone, MergedObject, Default)]
+#[derive(Debug, Clone, Default)]
 pub struct RootQuery;
 
-impl RootQuery {}
+#[Object]
+impl RootQuery {
+    /// Retrieves all Beamline Sessions
+    async fn sessions(&self, ctx: &Context<'_>) -> Result<Vec<Session>, async_graphql::Error> {
+        let database = ctx.data::<DatabaseConnection>()?;
+        Ok(bl_session::Entity::find()
+            .all(database)
+            .await?
+            .into_iter()
+            .map(Session::from)
+            .collect())
+    }
+
+    /// Retrieves a Beamline Session
+    async fn session(
+        &self,
+        ctx: &Context<'_>,
+        session_id: u32,
+    ) -> Result<Option<Session>, async_graphql::Error> {
+        let database = ctx.data::<DatabaseConnection>()?;
+        Ok(bl_session::Entity::find_by_id(session_id)
+            .one(database)
+            .await?
+            .map(Session::from))
+    }
+}