Override event thread startup wait time from environment

Add `HAB_EVENT_THREAD_STARTUP_WAIT_SEC` to your environment and have
fun!

Because hard-coded magic numbers suuuuuuuuuuuuuuck!

Signed-off-by: Christopher Maier <cmaier@chef.io>

components/sup/src/event.rs

@@ -53,8 +53,11 @@ pub use error::{Error,
 use futures::sync::mpsc::UnboundedSender;
 use habitat_common::types::{AutomateAuthToken,
                             EventStreamMetadata};
+use habitat_core::env::Config as EnvConfig;
 use state::Container;
 use std::{net::SocketAddr,
+          num::ParseIntError,
+          str::FromStr,
           sync::Once,
           time::Duration};
 
@@ -254,3 +257,28 @@ impl EventStream {
         }
     }
 }
+
+////////////////////////////////////////////////////////////////////////
+
+/// How long should we for the event thread to start up before
+/// abandoning it and shutting down?
+#[derive(Clone, Debug)]
+struct EventThreadStartupWait(u64);
+
+impl Default for EventThreadStartupWait {
+    fn default() -> Self { Self(5) }
+}
+
+impl FromStr for EventThreadStartupWait {
+    type Err = ParseIntError;
+
+    fn from_str(s: &str) -> ::std::result::Result<Self, Self::Err> { Ok(Self(s.parse()?)) }
+}
+
+impl EnvConfig for EventThreadStartupWait {
+    const ENVVAR: &'static str = "HAB_EVENT_THREAD_STARTUP_WAIT_SEC";
+}
+
+impl Into<Duration> for EventThreadStartupWait {
+    fn into(self) -> Duration { Duration::from_secs(self.0) }
+}

components/sup/src/event/nitox.rs

@@ -1,17 +1,18 @@
+use super::EventThreadStartupWait;
 use crate::event::{Error,
                    EventConnectionInfo,
                    EventStream,
                    Result};
 use futures::{sync::mpsc as futures_mpsc,
               Future,
               Stream};
+use habitat_core::env::Config as _;
 use nitox::{commands::ConnectCommand,
             streaming::client::NatsStreamingClient,
             NatsClient,
             NatsClientOptions};
 use std::{sync::mpsc as std_mpsc,
-          thread,
-          time::Duration};
+          thread};
 use tokio::{executor,
             runtime::current_thread::Runtime as ThreadRuntime};
 /// All messages are published under this subject.
@@ -83,7 +84,7 @@ pub(super) fn init_stream(conn_info: EventConnectionInfo) -> Result<EventStream>
                           })
                           .map_err(Error::SpawnEventThreadError)?;
 
-    sync_rx.recv_timeout(Duration::from_secs(5))
+    sync_rx.recv_timeout(EventThreadStartupWait::configured_value().into())
            .map_err(Error::ConnectEventServerError)?;
     Ok(EventStream(event_tx))
 }

components/sup/src/event/ratsio.rs

@@ -1,17 +1,18 @@
+use super::EventThreadStartupWait;
 use crate::event::{Error,
                    EventConnectionInfo,
                    EventStream,
                    Result};
 use futures::{sync::mpsc as futures_mpsc,
               Future,
               Stream};
+use habitat_core::env::Config as _;
 use ratsio::{nats_client::NatsClientOptions,
              stan_client::{StanClient,
                            StanMessage,
                            StanOptions}};
 use std::{sync::mpsc as std_mpsc,
-          thread,
-          time::Duration};
+          thread};
 use tokio::{executor,
             runtime::current_thread::Runtime as ThreadRuntime};
 
@@ -78,7 +79,7 @@ pub(super) fn init_stream(conn_info: EventConnectionInfo) -> Result<EventStream>
                           })
                           .map_err(Error::SpawnEventThreadError)?; // TODO (CM): ratsio error variant
 
-    sync_rx.recv_timeout(Duration::from_secs(5))
+    sync_rx.recv_timeout(EventThreadStartupWait::configured_value().into())
            .map_err(Error::ConnectEventServerError)?;
     Ok(EventStream(event_tx))
 }