From 6449757005637a8a733040f0a028dbfe6c958269 Mon Sep 17 00:00:00 2001
From: Mike Dilger <mike@mikedilger.com>
Date: Tue, 20 Dec 2022 18:42:28 +1300
Subject: [PATCH] Globals/GLOBALS

---
 src/globals.rs | 35 +++++++++++++++++++++++++++++++++++
 src/main.rs    |  4 ++++
 2 files changed, 39 insertions(+)
 create mode 100644 src/globals.rs

diff --git a/src/globals.rs b/src/globals.rs
new file mode 100644
index 00000000..884f9f21
--- /dev/null
+++ b/src/globals.rs
@@ -0,0 +1,35 @@
+use crate::comms::BusMessage;
+use tokio::sync::{broadcast, mpsc, Mutex};
+
+/// Only one of these is ever created, via lazy_static!, and represents
+/// global state for the rust application
+pub struct Globals {
+    /// This is a broadcast channel. All Minions should listen on it.
+    /// To create a receiver, just run .subscribe() on it.
+    pub to_minions: broadcast::Sender<BusMessage>,
+
+    /// This is a mpsc channel. The Overlord listens on it.
+    /// To create a sender, just clone() it.
+    pub to_overlord: mpsc::UnboundedSender<BusMessage>,
+
+    /// This is ephemeral. It is filled during lazy_static initialization,
+    /// and stolen away when the Overlord is created.
+    pub from_minions: Mutex<Option<mpsc::UnboundedReceiver<BusMessage>>>,
+}
+
+lazy_static! {
+    pub static ref GLOBALS: Globals = {
+
+        // Setup a communications channel from the Overlord to the Minions.
+        let (to_minions, _) = broadcast::channel(16);
+
+        // Setup a communications channel from the Minions to the Overlord.
+        let (to_overlord, from_minions) = mpsc::unbounded_channel();
+
+        Globals {
+            to_minions,
+            to_overlord,
+            from_minions: Mutex::new(Some(from_minions)),
+        }
+    };
+}
diff --git a/src/main.rs b/src/main.rs
index 46e8166a..7fb960e8 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,5 +1,9 @@
+#[macro_use]
+extern crate lazy_static;
+
 mod comms;
 mod error;
+mod globals;
 
 fn main() {
     tracing_subscriber::fmt::init();