feat: help for preparing sqlx query data

cli/src/db.rs

@@ -33,6 +33,8 @@ enum Command {
     Migrate,
     #[command(about = "Create a new migration")]
     NewMigration { title: String },
+    #[command(about = "Prepare sqlx query metadata for offline compile-time verification")]
+    Prepare,
 }
 
 #[async_std::main]
@@ -48,7 +50,6 @@ async fn main() {
             create_db(&db_config)
                 .await
                 .expect("Failed creating database.");
-
             migrate_db(&db_config)
                 .await
                 .expect("Failed migrating database.");
@@ -57,11 +58,9 @@ async fn main() {
             drop_db(&db_config)
                 .await
                 .expect("Failed dropping database.");
-
             create_db(&db_config)
                 .await
                 .expect("Failed creating database.");
-
             migrate_db(&db_config)
                 .await
                 .expect("Failed migrating database.");
@@ -76,6 +75,7 @@ async fn main() {
                 .await
                 .expect("Failed creating new migration.");
         }
+        Command::Prepare => prepare().await.expect("Failed preparing query metadata."),
     }
 }
 
@@ -169,6 +169,35 @@ async fn create_new_migration(title: &str) -> anyhow::Result<()> {
     Ok(())
 }
 
+async fn prepare() -> anyhow::Result<()> {
+    let cargo = std::env::var("CARGO")
+        .map_err(|_| anyhow::anyhow!("Please invoke me using Cargo, e.g.: `cargo db <ARGS>`"))
+        .expect("Existence of CARGO env var is asserted by calling `ensure_sqlx_cli_installed`");
+
+    let mut sqlx_prepare_command = {
+        let mut cmd = std::process::Command::new(&cargo);
+
+        cmd.args(["sqlx", "prepare", "--", "--all-targets", "--all-features"]);
+
+        let cmd_cwd = db_package_root().context("Error finding the root of the db package!")?;
+        cmd.current_dir(cmd_cwd);
+
+        cmd
+    };
+
+    let o = sqlx_prepare_command
+        .output()
+        .context("Could not run {cargo} sqlx prepare!")?;
+
+    if !o.status.success() {
+        let error = anyhow::anyhow!(String::from_utf8_lossy(&o.stdout).to_string()).context("Error generating query metadata. Are you sure the database is running and all migrations are applied?");
+        return Err(error);
+    }
+
+    println!("Query data written to db/.sqlx directory; please check this into version control.");
+    Ok(())
+}
+
 fn db_package_root() -> Result<PathBuf, anyhow::Error> {
     Ok(PathBuf::from(
         std::env::var("CARGO_MANIFEST_DIR").expect("This command needs to be invoked using cargo"),