#102 migrations working

CHANGELOG.md

@@ -5,15 +5,15 @@ By far most changes relate to `atomic-server`, so if not specified, assume the c
 
 ## UNRELEASED
 
-- **Warning**: Various default directories have moved (see #331). Most notably the `data` directory. The location depends on your OS. Run `show-config` to see where it will be stored now. If you have data in `~/.config/atomic/db`, move it to this new directory.
-- **Warning**: Search index will have to be rebuilt. Start with `--rebuild-index`.
+- **Warning**: Various default directories have moved (see #331). Most notably the `data` directory. The location depends on your OS. Run `show-config` to see where it will be stored now. If you have data in `~/.config/atomic/db`, move it to this new directory. Also, the search index will have to be rebuilt. Start with `--rebuild-index`.
 - Updated various dependencies, and made `cargo.toml` less restrictive.
 - Remove `async-std` calls from `upload.rs`
 - Added `reset` and `show-config` commands to `atomic-server`.
 - Added `data-dir` flag
 - Replaced `awc` with `ureq` #374
 - Get rid of `.unwrap` calls in `commit_monitor` #345
 - Make process management optional #324 #334
+- Internal migration logic for inter-version compatibility of the database. Makes upgrading trivial. #102
 
 ## [v0.31.1] - 2022-03-29
 

lib/src/db.rs

@@ -61,8 +61,6 @@ pub struct Db {
     /// A list of all the Collections currently being used. Is used to update `members_index`.
     /// See [collections_index]
     watched_queries: sled::Tree,
-    /// Contains settings such as schema versions.
-    internal: sled::Tree,
     /// The address where the db will be hosted, e.g. http://localhost/
     server_url: String,
     /// Endpoints are checked whenever a resource is requested. They calculate (some properties of) the resource and return it.
@@ -79,7 +77,6 @@ impl Db {
         let reference_index = db.open_tree("reference_index")?;
         let members_index = db.open_tree("members_index")?;
         let watched_queries = db.open_tree("watched_queries")?;
-        let internal = db.open_tree("internal")?;
         let store = Db {
             db,
             default_agent: Arc::new(Mutex::new(None)),
@@ -89,7 +86,6 @@ impl Db {
             server_url,
             watched_queries,
             endpoints: default_endpoints(),
-            internal,
         };
         migrate_maybe(&store)?;
         crate::populate::populate_base_models(&store)

lib/src/db/migrations.rs

@@ -6,7 +6,7 @@ Therefore, we need migrations to convert the old schema to the new one.
 
 ## Adding a Migration
 
-- Write a function called `v{OLD}_to_v{NEW} that takes a [Db].
+- Write a function called `v{OLD}_to_v{NEW} that takes a [Db]. Make sure it removed the old `Tree`. Use [assert] to check if the process worked.
 - In [migrate_maybe] add the key of the outdated Tree
 - Add the function to the [migrate_maybe] `match` statement, select the older version of the Tree
 - Update the Tree key used in [Db::init]
@@ -30,14 +30,19 @@ pub fn migrate_maybe(store: &Db) -> AtomicResult<()> {
 fn v0_to_v1(store: &Db) -> AtomicResult<()> {
     tracing::warn!("Migrating resources schema from v0 to v1...");
     let new = store.db.open_tree("resources_v1")?;
+    let old_key = "resources";
+    let old = store.db.open_tree(old_key)?;
     let mut count = 0;
 
-    let config = sled::Config::new().temporary(true);
-    let db = config.open().unwrap();
-
-    use sled::Transactional;
+    for item in old.into_iter() {
+        let (subject, resource_bin) = item.expect("Unable to convert into iterable");
+        let subject: String =
+            bincode::deserialize(&subject).expect("Unable to deserialize subject");
+        new.insert(subject.as_bytes(), resource_bin)?;
+        count += 1;
+    }
 
-    // TODO: Let this compile!:
+    // TODO: Prefer transactional approach, but issue preventing me from compiling:
     // https://github.com/spacejam/sled/issues/1406
     // (&store.resources, &new)
     //     .transaction(|(old, new)| {
@@ -57,6 +62,12 @@ fn v0_to_v1(store: &Db) -> AtomicResult<()> {
         store.resources.len(),
         "Not all resources were migrated."
     );
+
+    assert!(
+        store.db.drop_tree(old_key)?,
+        "Old resources tree not properly removed."
+    );
+
     tracing::warn!("Finished migration of {} resources", count);
     Ok(())
 }