Fix release build (#193)

PR #179 broke release builds by making it necessary for
`LiveAskQuestion` and `SEED` to both now be available regardless of
whether `debug_assertions` is set. That's unfortunate, since `SEED` in
particular would make the binary quite large. So I've instead made it so
that in release mode (or rather, without `debug_assertions`), `SEED` is
_not_ compiled in, and DynamoDB mode is _always_ used.

I've also added a CI job to check `--release --target
aarch64-unknown-linux-gnu` so that this can't happen in the future.

.github/workflows/check.yml

@@ -39,8 +39,25 @@ jobs:
         with:
           components: rustfmt
       - name: cargo fmt --check
-        run: cargo fmt --check --manifest-path server/Cargo.toml
         run: cargo fmt --check
+  in_release_mode_on_arm:
+    runs-on: ubuntu-latest
+    name: stable / release-arm
+    defaults:
+      run:
+        working-directory: ./server
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          submodules: true
+      - name: Install stable
+        uses: dtolnay/rust-toolchain@stable
+      - name: rustup target add aarch64-unknown-linux-gnu
+        run: rustup target add aarch64-unknown-linux-gnu
+      - name: Install aarch64-gcc
+        run: sudo apt-get install gcc-aarch64-linux-gnu
+      - name: cargo check --release --target aarch64-unknown-linux-gnu
+        run: cargo check --release --target aarch64-unknown-linux-gnu
   clippy:
     runs-on: ubuntu-latest
     name: ${{ matrix.toolchain }} / clippy

server/src/main.rs

@@ -167,7 +167,10 @@ async fn main() -> Result<(), Error> {
         .with_env_filter(EnvFilter::from_default_env())
         .without_time(/* cloudwatch does that */).init();
 
-    let backend = if !cfg!(debug_assertions) || std::env::var_os("USE_DYNAMODB").is_some() {
+    #[cfg(not(debug_assertions))]
+    let backend = Backend::dynamo().await;
+    #[cfg(debug_assertions)]
+    let backend = if std::env::var_os("USE_DYNAMODB").is_some() {
         Backend::dynamo().await
     } else {
         use rand::prelude::SliceRandom;