Add total history count to the index API (#1102)

Thought it would be fun to collect some cool stats, maybe put them on
atuin.sh.

atuin-common/src/api.rs

@@ -67,6 +67,7 @@ pub struct ErrorResponse<'a> {
 pub struct IndexResponse {
     pub homage: String,
     pub version: String,
+    pub total_history: i64,
 }
 
 #[derive(Debug, Serialize, Deserialize)]

atuin-server-database/src/lib.rs

@@ -52,6 +52,7 @@ pub trait Database: Sized + Clone + Send + Sync + 'static {
     async fn add_user(&self, user: &NewUser) -> DbResult<i64>;
     async fn delete_user(&self, u: &User) -> DbResult<()>;
 
+    async fn total_history(&self) -> DbResult<i64>;
     async fn count_history(&self, user: &User) -> DbResult<i64>;
     async fn count_history_cached(&self, user: &User) -> DbResult<i64>;
 

atuin-server-postgres/src/lib.rs

@@ -100,6 +100,21 @@ impl Database for Postgres {
         Ok(res.0)
     }
 
+    #[instrument(skip_all)]
+    async fn total_history(&self) -> DbResult<i64> {
+        // The cache is new, and the user might not yet have a cache value.
+        // They will have one as soon as they post up some new history, but handle that
+        // edge case.
+
+        let res: (i64,) = sqlx::query_as("select sum(total) from total_history_count_user")
+            .fetch_optional(&self.pool)
+            .await
+            .map_err(fix_error)?
+            .unwrap_or((0,));
+
+        Ok(res.0)
+    }
+
     #[instrument(skip_all)]
     async fn count_history_cached(&self, user: &User) -> DbResult<i64> {
         let res: (i32,) = sqlx::query_as(

atuin-server/src/handlers/mod.rs

@@ -1,5 +1,8 @@
 use atuin_common::api::{ErrorResponse, IndexResponse};
-use axum::{response::IntoResponse, Json};
+use atuin_server_database::Database;
+use axum::{extract::State, response::IntoResponse, Json};
+
+use crate::router::AppState;
 
 pub mod history;
 pub mod record;
@@ -8,12 +11,17 @@ pub mod user;
 
 const VERSION: &str = env!("CARGO_PKG_VERSION");
 
-pub async fn index() -> Json<IndexResponse> {
+pub async fn index<DB: Database>(state: State<AppState<DB>>) -> Json<IndexResponse> {
     let homage = r#""Through the fathomless deeps of space swims the star turtle Great A'Tuin, bearing on its back the four giant elephants who carry on their shoulders the mass of the Discworld." -- Sir Terry Pratchett"#;
 
+    // Error with a -1 response
+    // It's super unlikley this will happen
+    let count = state.database.total_history().await.unwrap_or(-1);
+
     Json(IndexResponse {
         homage: homage.to_string(),
         version: VERSION.to_string(),
+        total_history: count,
     })
 }