Have ipx add, rm and import tell a running daemon to read the catalogue again (#120)

`docker exec iPX ipx rm make` printed "removed make" and took it out of the catalogue table, but
the web UI went on listing it. add, rm and import run in a process of their own and write the
whole catalogue there; the daemon kept its own copy in memory, and its next change of its own --
an admin's edit, a feed categorised (#117), a moved feed followed (#115) -- wrote the removed
feed back and dropped any the command line had added.

A new socket command, reload, has the daemon read the catalogue and settings again from the
database. The socket answers it at once, as it answers status, with the counts after it: queued
behind a scan, the web UI could write the old copy back in the meantime. add, rm and import send
it when a daemon is live, and say so if it does not answer. User commands need nothing: the
daemon reads accounts from the database on every request.

A browser test runs the real `ipx add --list` and `ipx rm` against the test daemon, with an
admin's edit after each, and fails without this.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/main.rs

@@ -249,9 +249,13 @@ async fn main() -> Result<()> {
         return ipc::proxy(&cfg.general.socket, cmd).await;
     }
 
+    let socket = cfg.general.socket.clone();
     let cfg = assemble_config(&db, cfg, &config_path).await?;
 
     let is_daemon = matches!(cli.command, Command::Daemon { .. });
+    // These write the catalogue from a process of their own, which a running daemon, holding its
+    // own copy, would write over at its next change (#120).
+    let changes_catalogue = matches!(cli.command, Command::Add { .. } | Command::Rm { .. } | Command::Import { .. });
     let (events, _) = broadcast::channel(1024);
     let ctx = Arc::new(Ctx {
         cfg: std::sync::RwLock::new(std::sync::Arc::new(cfg)),
@@ -285,6 +289,11 @@ async fn main() -> Result<()> {
         Command::Export { file } => export(&ctx, &file).await,
         _ => run(&ctx, wire_cmd.expect("only List and Daemon have no wire form")).await,
     };
+    if result.is_ok() && changes_catalogue && ipc::daemon_is_live(&socket).await {
+        if let Err(e) = ipc::reload(&socket).await {
+            eprintln!("the running daemon did not take the change ({e:#}); restart it, or it may undo it");
+        }
+    }
     // The batch exporter holds the last few seconds of spans; without this they are lost.
     if let Some(p) = otel {
         let _ = p.shutdown();
@@ -452,9 +461,19 @@ async fn run(ctx: &Arc<Ctx>, cmd: Cmd) -> Result<()> {
             ctx.out.emit(status(ctx).await);
             Ok(())
         }
+        Cmd::Reload => reload(ctx).await,
     }
 }
 
+/// The catalogue and server settings as the database now has them, in place of the copy in
+/// memory, for a daemon told another ipx changed them (#120); config.toml, read again, for where
+/// things are and who gets in.
+async fn reload(ctx: &Ctx) -> Result<()> {
+    let cfg = assemble_config(&ctx.db, config::Config::load(&ctx.config_path)?, &ctx.config_path).await?;
+    ctx.set_cfg(cfg);
+    Ok(())
+}
+
 /// The counts `ipx status` prints, and /api/status serves. A running daemon's socket answers with
 /// this directly rather than through the job queue.
 pub(crate) async fn status(ctx: &Ctx) -> Event {
@@ -511,12 +530,20 @@ async fn daemon(
     let (tx_cmd, mut rx_cmd) = mpsc::channel::<Cmd>(64);
 
     let web = start_web(&ctx, &config_path, web_addr, &tx_cmd, &events).await?;
-    // status is answered by the socket itself; everything else waits its turn in the queue.
+    // status and reload are answered by the socket itself; everything else waits its turn in the
+    // queue.
     let answer: ipc::StatusFn = {
         let ctx = ctx.clone();
-        Arc::new(move || {
+        Arc::new(move |cmd| {
             let ctx = ctx.clone();
-            Box::pin(async move { status(&ctx).await })
+            Box::pin(async move {
+                if matches!(cmd, Cmd::Reload)
+                    && let Err(e) = reload(&ctx).await
+                {
+                    return Event::Error { msg: format!("reading the catalogue again: {e:#}") };
+                }
+                status(&ctx).await
+            })
         })
     };
     let server = tokio::spawn(ipc::serve(socket.clone(), events.clone(), tx_cmd, answer));
@@ -2255,6 +2282,23 @@ mod tests {
         }
     }
 
+    #[tokio::test]
+    async fn a_reload_takes_the_catalogue_another_ipx_wrote() {
+        let with = |id: &str| {
+            let mut cfg = config::Config::default();
+            cfg.feeds.insert(id.into(), config::Feed { url: format!("http://x/{id}.xml"), ..feed() });
+            cfg
+        };
+        let held = with("kept-in-memory");
+        let ctx = test_ctx(held.clone()).await;
+        ctx.db.store_config(&held).await.unwrap();
+        // `ipx add` and `ipx rm`, from a process of their own (#120).
+        ctx.db.store_config(&with("added-by-the-cli")).await.unwrap();
+        reload(&ctx).await.unwrap();
+        let urls: Vec<String> = ctx.cfg().feeds.values().map(|f| f.url.clone()).collect();
+        assert_eq!(urls, vec!["http://x/added-by-the-cli.xml".to_string()]);
+    }
+
     /// Answers /empty with a 200 and nothing, anything else with a feed of one item.
     async fn empty_or_feed_server() -> String {
         use tokio::io::{AsyncReadExt, AsyncWriteExt};