Do not require db url for prepare

sqlx-cli/src/database.rs

@@ -17,14 +17,14 @@ pub async fn create(connect_opts: &ConnectOpts) -> anyhow::Result<()> {
             std::sync::atomic::Ordering::Release,
         );
 
-        Any::create_database(&connect_opts.database_url).await?;
+        Any::create_database(connect_opts.required_db_url()?).await?;
     }
 
     Ok(())
 }
 
 pub async fn drop(connect_opts: &ConnectOpts, confirm: bool) -> anyhow::Result<()> {
-    if confirm && !ask_to_continue(connect_opts) {
+    if confirm && !ask_to_continue_drop(connect_opts.required_db_url()?) {
         return Ok(());
     }
 
@@ -33,7 +33,7 @@ pub async fn drop(connect_opts: &ConnectOpts, confirm: bool) -> anyhow::Result<(
     let exists = crate::retry_connect_errors(connect_opts, Any::database_exists).await?;
 
     if exists {
-        Any::drop_database(&connect_opts.database_url).await?;
+        Any::drop_database(connect_opts.required_db_url()?).await?;
     }
 
     Ok(())
@@ -53,12 +53,10 @@ pub async fn setup(migration_source: &str, connect_opts: &ConnectOpts) -> anyhow
     migrate::run(migration_source, connect_opts, false, false, None).await
 }
 
-fn ask_to_continue(connect_opts: &ConnectOpts) -> bool {
+fn ask_to_continue_drop(db_url: &str) -> bool {
     loop {
-        let r: Result<String, ReadlineError> = prompt(format!(
-            "Drop database at {}? (y/n)",
-            style(&connect_opts.database_url).cyan()
-        ));
+        let r: Result<String, ReadlineError> =
+            prompt(format!("Drop database at {}? (y/n)", style(db_url).cyan()));
         match r {
             Ok(response) => {
                 if response == "n" || response == "N" {

sqlx-cli/src/lib.rs

@@ -101,7 +101,7 @@ pub async fn run(opt: Opt) -> Result<()> {
 }
 
 /// Attempt to connect to the database server, retrying up to `ops.connect_timeout`.
-async fn connect(opts: &ConnectOpts) -> sqlx::Result<AnyConnection> {
+async fn connect(opts: &ConnectOpts) -> anyhow::Result<AnyConnection> {
     retry_connect_errors(opts, AnyConnection::connect).await
 }
 
@@ -112,32 +112,34 @@ async fn connect(opts: &ConnectOpts) -> sqlx::Result<AnyConnection> {
 async fn retry_connect_errors<'a, F, Fut, T>(
     opts: &'a ConnectOpts,
     mut connect: F,
-) -> sqlx::Result<T>
+) -> anyhow::Result<T>
 where
     F: FnMut(&'a str) -> Fut,
     Fut: Future<Output = sqlx::Result<T>> + 'a,
 {
     sqlx::any::install_default_drivers();
 
+    let db_url = opts.required_db_url()?;
+
     backoff::future::retry(
         backoff::ExponentialBackoffBuilder::new()
             .with_max_elapsed_time(Some(Duration::from_secs(opts.connect_timeout)))
             .build(),
         || {
-            connect(&opts.database_url).map_err(|e| -> backoff::Error<sqlx::Error> {
+            connect(db_url).map_err(|e| -> backoff::Error<anyhow::Error> {
                 match e {
                     sqlx::Error::Io(ref ioe) => match ioe.kind() {
                         io::ErrorKind::ConnectionRefused
                         | io::ErrorKind::ConnectionReset
                         | io::ErrorKind::ConnectionAborted => {
-                            return backoff::Error::transient(e);
+                            return backoff::Error::transient(e.into());
                         }
                         _ => (),
                     },
                     _ => (),
                 }
 
-                backoff::Error::permanent(e)
+                backoff::Error::permanent(e.into())
             })
         },
     )

sqlx-cli/src/opt.rs

@@ -229,9 +229,9 @@ impl Deref for Source {
 /// Argument for the database URL.
 #[derive(Args, Debug)]
 pub struct ConnectOpts {
-    /// Location of the DB, by default will be read from the DATABASE_URL env var
+    /// Location of the DB, by default will be read from the DATABASE_URL env var or `.env` files.
     #[clap(long, short = 'D', env)]
-    pub database_url: String,
+    pub database_url: Option<String>,
 
     /// The maximum time, in seconds, to try connecting to the database server before
     /// returning an error.
@@ -251,6 +251,18 @@ pub struct ConnectOpts {
     pub sqlite_create_db_wal: bool,
 }
 
+impl ConnectOpts {
+    /// Require a database URL to be provided, otherwise
+    /// return an error.
+    pub fn required_db_url(&self) -> anyhow::Result<&str> {
+        self.database_url.as_deref().ok_or_else(
+            || anyhow::anyhow!(
+                "the `--database-url` option the or `DATABASE_URL` environment variable must be provided"
+            )
+        )
+    }
+}
+
 /// Argument for automatic confirmation.
 #[derive(Args, Copy, Clone, Debug)]
 pub struct Confirmation {

sqlx-cli/src/prepare.rs

@@ -8,8 +8,6 @@ use std::process::Command;
 use anyhow::{bail, Context};
 use console::style;
 
-use sqlx::Connection;
-
 use crate::metadata::{manifest_dir, Metadata};
 use crate::opt::ConnectOpts;
 
@@ -64,8 +62,6 @@ hint: This command only works in the manifest directory of a Cargo package or wo
 }
 
 async fn prepare(ctx: &PrepareCtx) -> anyhow::Result<()> {
-    check_backend(&ctx.connect_opts).await?;
-
     let prepare_dir = ctx.prepare_dir()?;
     run_prepare_step(ctx, &prepare_dir)?;
 
@@ -90,8 +86,6 @@ async fn prepare(ctx: &PrepareCtx) -> anyhow::Result<()> {
 }
 
 async fn prepare_check(ctx: &PrepareCtx) -> anyhow::Result<()> {
-    let _ = check_backend(&ctx.connect_opts).await?;
-
     // Re-generate and store the queries in a separate directory from both the prepared
     // queries and the ones generated by `cargo check`, to avoid conflicts.
     let prepare_dir = ctx.prepare_dir()?;
@@ -172,10 +166,13 @@ fn run_prepare_step(ctx: &PrepareCtx, cache_dir: &Path) -> anyhow::Result<()> {
             .arg("check")
             .args(&ctx.cargo_args)
             .env("SQLX_TMP", tmp_dir)
-            .env("DATABASE_URL", &ctx.connect_opts.database_url)
             .env("SQLX_OFFLINE", "false")
             .env("SQLX_OFFLINE_DIR", cache_dir);
 
+        if let Some(database_url) = &ctx.connect_opts.database_url {
+            check_command.env("DATABASE_URL", database_url);
+        }
+
         // `cargo check` recompiles on changed rust flags which can be set either via the env var
         // or through the `rustflags` field in `$CARGO_HOME/config` when the env var isn't set.
         // Because of this we only pass in `$RUSTFLAGS` when present.
@@ -320,12 +317,6 @@ fn minimal_project_recompile_action(metadata: &Metadata) -> ProjectRecompileActi
     }
 }
 
-/// Ensure the database server is available.
-async fn check_backend(opts: &ConnectOpts) -> anyhow::Result<()> {
-    crate::connect(opts).await?.close().await?;
-    Ok(())
-}
-
 /// Find all `query-*.json` files in a directory.
 fn glob_query_files(path: impl AsRef<Path>) -> anyhow::Result<Vec<PathBuf>> {
     let path = path.as_ref();