chore: improve dfx start messages.

CHANGELOG.md

@@ -37,6 +37,14 @@ How to resolve the error:
 Run the command with '--ic' flag if you want to manage the cycles on the mainnet.
 ```
 
+### chore: improve `dfx start` messages.
+
+For `dfx start`, show below messages to users to indicate what to do next.
+```
+Success! The dfx server is running.
+You must open a new terminal to continue developing. If you'd prefer to stop, quit with 'Ctrl-C'.
+```
+
 # 0.24.2
 
 ### feat: Support canister log allowed viewer list

e2e/tests-dfx/start.bash

@@ -60,7 +60,8 @@ teardown() {
 }
 
 @test "start and stop outside project" {
-  dfx_start
+  assert_command dfx_start
+  assert_contains "Success! The dfx server is running in the background."
 
   mkdir subdir
   cd subdir || exit 1

src/dfx/src/actors/mod.rs

@@ -13,6 +13,7 @@ use dfx_core::config::model::replica_config::ReplicaConfig;
 use fn_error_context::context;
 use pocketic_proxy::signals::PortReadySubscribe;
 use pocketic_proxy::{PocketIcProxy, PocketIcProxyConfig};
+use post_start::PostStart;
 use std::fs;
 use std::path::PathBuf;
 
@@ -22,6 +23,7 @@ pub mod btc_adapter;
 pub mod canister_http_adapter;
 pub mod pocketic;
 pub mod pocketic_proxy;
+pub mod post_start;
 pub mod replica;
 mod shutdown;
 pub mod shutdown_controller;
@@ -214,3 +216,17 @@ pub fn start_pocketic_actor(
     };
     Ok(pocketic::PocketIc::new(actor_config).start())
 }
+
+#[context("Failed to start PostStart actor.")]
+pub fn start_post_start_actor(
+    env: &dyn Environment,
+    background: bool,
+    pocketic_proxy: Option<Addr<PocketIcProxy>>,
+) -> DfxResult<Addr<PostStart>> {
+    let config = post_start::Config {
+        logger: env.get_logger().clone(),
+        background,
+        pocketic_proxy,
+    };
+    Ok(PostStart::new(config).start())
+}

src/dfx/src/actors/pocketic_proxy.rs

@@ -1,4 +1,5 @@
 use crate::actors::pocketic_proxy::signals::{PortReadySignal, PortReadySubscribe};
+use crate::actors::post_start::signals::{PocketIcProxyReadySignal, PocketIcProxyReadySubscribe};
 use crate::actors::shutdown::{wait_for_child_or_receiver, ChildOrReceiver};
 use crate::actors::shutdown_controller::signals::outbound::Shutdown;
 use crate::actors::shutdown_controller::signals::ShutdownSubscribe;
@@ -70,6 +71,9 @@ pub struct PocketIcProxy {
 
     stop_sender: Option<Sender<()>>,
     thread_join: Option<JoinHandle<()>>,
+
+    /// Ready Signal subscribers.
+    ready_subscribers: Vec<Recipient<PocketIcProxyReadySignal>>,
 }
 
 impl PocketIcProxy {
@@ -81,10 +85,11 @@ impl PocketIcProxy {
             stop_sender: None,
             thread_join: None,
             logger,
+            ready_subscribers: Vec::new(),
         }
     }
 
-    fn start_pocketic_proxy(&mut self, replica_url: Url) -> DfxResult {
+    fn start_pocketic_proxy(&mut self, replica_url: Url, addr: Addr<Self>) -> DfxResult {
         let logger = self.logger.clone();
         let config = &self.config.pocketic_proxy_config;
         let pocketic_proxy_path = self.config.pocketic_proxy_path.clone();
@@ -100,6 +105,7 @@ impl PocketIcProxy {
                 pocketic_proxy_path,
                 pocketic_proxy_pid_path,
                 pocketic_proxy_port_path,
+                addr,
                 receiver,
                 config.verbose,
                 config.domains.clone(),
@@ -164,7 +170,7 @@ impl Actor for PocketIcProxy {
             .do_send(ShutdownSubscribe(ctx.address().recipient::<Shutdown>()));
 
         if let Some(replica_url) = &self.config.pocketic_proxy_config.replica_url {
-            self.start_pocketic_proxy(replica_url.clone())
+            self.start_pocketic_proxy(replica_url.clone(), ctx.address())
                 .expect("Could not start PocketIC HTTP gateway");
         }
     }
@@ -179,7 +185,7 @@ impl Actor for PocketIcProxy {
 impl Handler<PortReadySignal> for PocketIcProxy {
     type Result = ();
 
-    fn handle(&mut self, msg: PortReadySignal, _ctx: &mut Self::Context) {
+    fn handle(&mut self, msg: PortReadySignal, ctx: &mut Self::Context) {
         debug!(
             self.logger,
             "replica ready on {}, so re/starting HTTP gateway", msg.url
@@ -189,11 +195,29 @@ impl Handler<PortReadySignal> for PocketIcProxy {
 
         let replica_url = Url::parse(&msg.url).unwrap();
 
-        self.start_pocketic_proxy(replica_url)
+        self.start_pocketic_proxy(replica_url, ctx.address())
             .expect("Could not start PocketIC HTTP gateway");
     }
 }
 
+impl Handler<PocketIcProxyReadySubscribe> for PocketIcProxy {
+    type Result = ();
+
+    fn handle(&mut self, msg: PocketIcProxyReadySubscribe, _ctx: &mut Self::Context) {
+        self.ready_subscribers.push(msg.0);
+    }
+}
+
+impl Handler<PocketIcProxyReadySignal> for PocketIcProxy {
+    type Result = ();
+
+    fn handle(&mut self, _msg: PocketIcProxyReadySignal, _ctx: &mut Self::Context) {
+        for sub in &self.ready_subscribers {
+            sub.do_send(PocketIcProxyReadySignal);
+        }
+    }
+}
+
 impl Handler<Shutdown> for PocketIcProxy {
     type Result = ResponseActFuture<Self, Result<(), ()>>;
 
@@ -217,6 +241,7 @@ fn pocketic_proxy_start_thread(
     pocketic_proxy_path: PathBuf,
     pocketic_proxy_pid_path: PathBuf,
     pocketic_proxy_port_path: PathBuf,
+    addr: Addr<PocketIcProxy>,
     receiver: Receiver<()>,
     verbose: bool,
     domains: Option<Vec<String>>,
@@ -277,6 +302,9 @@ fn pocketic_proxy_start_thread(
             }
             info!(logger, "Replica API running on {address}");
 
+            // Send PocketIcProxyReadySignal to PocketIcProxy.
+            addr.do_send(PocketIcProxyReadySignal);
+
             // This waits for the child to stop, or the receiver to receive a message.
             // We don't restart pocket-ic if done = true.
             match wait_for_child_or_receiver(&mut child, &receiver) {

src/dfx/src/actors/post_start.rs

@@ -0,0 +1,62 @@
+use crate::actors::pocketic_proxy::PocketIcProxy;
+use crate::actors::post_start::signals::{PocketIcProxyReadySignal, PocketIcProxyReadySubscribe};
+use actix::{Actor, Addr, AsyncContext, Context, Handler};
+use slog::{info, Logger};
+
+pub mod signals {
+    use actix::prelude::*;
+
+    #[derive(Message)]
+    #[rtype(result = "()")]
+    pub struct PocketIcProxyReadySignal;
+
+    #[derive(Message)]
+    #[rtype(result = "()")]
+    pub struct PocketIcProxyReadySubscribe(pub Recipient<PocketIcProxyReadySignal>);
+}
+
+pub struct Config {
+    pub logger: Logger,
+    pub background: bool,
+    pub pocketic_proxy: Option<Addr<PocketIcProxy>>,
+}
+
+pub struct PostStart {
+    config: Config,
+}
+
+impl PostStart {
+    pub fn new(config: Config) -> Self {
+        Self { config }
+    }
+}
+
+impl Actor for PostStart {
+    type Context = Context<Self>;
+
+    fn started(&mut self, ctx: &mut Self::Context) {
+        // Register the PostStart recipent to PocketIcProxy.
+        if let Some(pocketic_proxy) = &self.config.pocketic_proxy {
+            pocketic_proxy.do_send(PocketIcProxyReadySubscribe(ctx.address().recipient()));
+        }
+    }
+}
+
+impl Handler<PocketIcProxyReadySignal> for PostStart {
+    type Result = ();
+
+    fn handle(&mut self, _msg: PocketIcProxyReadySignal, _ctx: &mut Self::Context) -> Self::Result {
+        let logger = &self.config.logger;
+        if self.config.background {
+            info!(
+                logger,
+                "Success! The dfx server is running in the background."
+            )
+        } else {
+            info!(
+                logger,
+                "Success! The dfx server is running.\nYou must open a new terminal to continue developing. If you'd prefer to stop, quit with 'Ctrl-C'."
+            )
+        }
+    }
+}

src/dfx/src/commands/start.rs

@@ -1,7 +1,8 @@
 use crate::actors::pocketic_proxy::{signals::PortReadySubscribe, PocketIcProxyConfig};
 use crate::actors::{
     start_btc_adapter_actor, start_canister_http_adapter_actor, start_pocketic_actor,
-    start_pocketic_proxy_actor, start_replica_actor, start_shutdown_controller,
+    start_pocketic_proxy_actor, start_post_start_actor, start_replica_actor,
+    start_shutdown_controller,
 };
 use crate::config::dfx_version_str;
 use crate::error_invalid_argument;
@@ -49,6 +50,10 @@ pub struct StartOpts {
     #[arg(long)]
     background: bool,
 
+    /// Indicates if the actual dfx process is running in the background.
+    #[arg(long, env = "DFX_RUNNING_IN_BACKGROUND", hide = true)]
+    running_in_background: bool,
+
     /// Cleans the state of the current project.
     #[arg(long)]
     clean: bool,
@@ -138,6 +143,7 @@ pub fn exec(
     StartOpts {
         host,
         background,
+        running_in_background,
         clean,
         force,
         bitcoin_node,
@@ -413,7 +419,10 @@ pub fn exec(
             pocketic_proxy_pid_file_path,
             pocketic_proxy_port_file_path,
         )?;
-        Ok::<_, Error>(proxy)
+
+        let post_start = start_post_start_actor(env, running_in_background, Some(proxy))?;
+
+        Ok::<_, Error>(post_start)
     })?;
     system.run()?;
 
@@ -574,7 +583,8 @@ fn send_background() -> DfxResult<()> {
             .skip(1)
             .filter(|a| !a.eq("--background"))
             .filter(|a| !a.eq("--clean")),
-    );
+    )
+    .env("DFX_RUNNING_IN_BACKGROUND", "true"); // Set the `DFX_RUNNING_IN_BACKGROUND` environment variable which will be used by the second start.
 
     cmd.spawn().context("Failed to spawn child process.")?;
     Ok(())