Logging + database migrations system.

src/database/migrations/scripts.rs

@@ -0,0 +1,53 @@
+use super::super::get_collection;
+
+use serde::{Serialize, Deserialize};
+use mongodb::bson::{Bson, from_bson, doc};
+use log::info;
+
+#[derive(Serialize, Deserialize)]
+struct MigrationInfo {
+    _id: i32,
+    revision: i32
+}
+
+pub const LATEST_REVISION: i32 = 1;
+
+pub fn migrate_database() {
+    let migrations = get_collection("migrations");
+    let data = migrations.find_one(None, None)
+        .expect("Failed to fetch migration data.");
+    
+    if let Some(doc) = data {
+        let info: MigrationInfo = from_bson(Bson::Document(doc))
+            .expect("Failed to read migration information.");
+        
+        let revision = run_migrations(info.revision);
+
+        migrations.update_one(
+            doc! {
+                "_id": info._id
+            },
+            doc! {
+                "$set": {
+                    "revision": revision
+                }
+            },
+            None
+        ).expect("Failed to commit migration information.");
+
+        info!("Migration complete. Currently at revision {}.", revision);
+    } else {
+        panic!("Database was configured incorrectly, possibly because initalization failed.")
+    }
+}
+
+pub fn run_migrations(revision: i32) -> i32 {
+    info!("Starting database migration.");
+
+    if revision <= 0 {
+        info!("Running migration [revision 0]: Test migration system.");
+    }
+
+    // Reminder to update LATEST_REVISION when adding new migrations.
+    LATEST_REVISION
+}