From ef298f59e539466d8ca53ef77ee73efa31626cc9 Mon Sep 17 00:00:00 2001
From: David Pacheco <dap@oxidecomputer.com>
Date: Fri, 23 Feb 2024 11:07:34 -0800
Subject: [PATCH 1/2] trigger inventory collection after blueprint execution

---
 .../src/app/background/blueprint_execution.rs | 13 ++++-
 nexus/src/app/background/init.rs              | 56 +++++++++++--------
 2 files changed, 44 insertions(+), 25 deletions(-)

diff --git a/nexus/src/app/background/blueprint_execution.rs b/nexus/src/app/background/blueprint_execution.rs
index 32797facbf..5ceff5d717 100644
--- a/nexus/src/app/background/blueprint_execution.rs
+++ b/nexus/src/app/background/blueprint_execution.rs
@@ -20,6 +20,8 @@ pub struct BlueprintExecutor {
     datastore: Arc<DataStore>,
     rx_blueprint: watch::Receiver<Option<Arc<(BlueprintTarget, Blueprint)>>>,
     nexus_label: String,
+    tx: watch::Sender<usize>,
+    count: usize,
 }
 
 impl BlueprintExecutor {
@@ -30,7 +32,12 @@ impl BlueprintExecutor {
         >,
         nexus_label: String,
     ) -> BlueprintExecutor {
-        BlueprintExecutor { datastore, rx_blueprint, nexus_label }
+        let (tx, _) = watch::channel(0);
+        BlueprintExecutor { datastore, rx_blueprint, nexus_label, tx, count: 0 }
+    }
+
+    pub fn watcher(&self) -> watch::Receiver<usize> {
+        self.tx.subscribe()
     }
 }
 
@@ -71,6 +78,10 @@ impl BackgroundTask for BlueprintExecutor {
             )
             .await;
 
+            // Trigger anybody waiting for this to finish.
+            self.count = self.count + 1;
+            self.tx.send(self.count);
+
             // Return the result as a `serde_json::Value`
             match result {
                 Ok(()) => json!({}),
diff --git a/nexus/src/app/background/init.rs b/nexus/src/app/background/init.rs
index 846051a068..9ba30bab64 100644
--- a/nexus/src/app/background/init.rs
+++ b/nexus/src/app/background/init.rs
@@ -170,30 +170,6 @@ impl BackgroundTasks {
             )
         };
 
-        // Background task: inventory collector
-        let task_inventory_collection = {
-            let collector = inventory_collection::InventoryCollector::new(
-                datastore.clone(),
-                resolver,
-                &nexus_id.to_string(),
-                config.inventory.nkeep,
-                config.inventory.disable,
-            );
-            let task = driver.register(
-                String::from("inventory_collection"),
-                String::from(
-                    "collects hardware and software inventory data from the \
-                    whole system",
-                ),
-                config.inventory.period_secs,
-                Box::new(collector),
-                opctx.child(BTreeMap::new()),
-                vec![],
-            );
-
-            task
-        };
-
         // Background task: phantom disk detection
         let task_phantom_disks = {
             let detector =
@@ -230,6 +206,7 @@ impl BackgroundTasks {
             rx_blueprint.clone(),
             nexus_id.to_string(),
         );
+        let rx_blueprint_exec = blueprint_executor.watcher();
         let task_blueprint_executor = driver.register(
             String::from("blueprint_executor"),
             String::from("Executes the target blueprint"),
@@ -239,6 +216,37 @@ impl BackgroundTasks {
             vec![Box::new(rx_blueprint)],
         );
 
+        // Background task: inventory collector
+        //
+        // This currently depends on the "output" of the blueprint executor in
+        // order to automatically trigger inventory collection whenever the
+        // blueprint executor runs.  In the limit, this could become a problem
+        // because the blueprint executor might also depend indirectly on the
+        // inventory collector.  In that case, we may need to do something more
+        // complicated.  But for now, this works.
+        let task_inventory_collection = {
+            let collector = inventory_collection::InventoryCollector::new(
+                datastore.clone(),
+                resolver,
+                &nexus_id.to_string(),
+                config.inventory.nkeep,
+                config.inventory.disable,
+            );
+            let task = driver.register(
+                String::from("inventory_collection"),
+                String::from(
+                    "collects hardware and software inventory data from the \
+                    whole system",
+                ),
+                config.inventory.period_secs,
+                Box::new(collector),
+                opctx.child(BTreeMap::new()),
+                vec![Box::new(rx_blueprint_exec)],
+            );
+
+            task
+        };
+
         let task_service_zone_nat_tracker = {
             driver.register(
                 "service_zone_nat_tracker".to_string(),

From 70dfed3dff440d3f0c168c492a064216b4eccbf9 Mon Sep 17 00:00:00 2001
From: David Pacheco <dap@oxidecomputer.com>
Date: Fri, 23 Feb 2024 11:36:58 -0800
Subject: [PATCH 2/2] fix

---
 nexus/src/app/background/blueprint_execution.rs | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/nexus/src/app/background/blueprint_execution.rs b/nexus/src/app/background/blueprint_execution.rs
index 5ceff5d717..2ad82e8c68 100644
--- a/nexus/src/app/background/blueprint_execution.rs
+++ b/nexus/src/app/background/blueprint_execution.rs
@@ -21,7 +21,6 @@ pub struct BlueprintExecutor {
     rx_blueprint: watch::Receiver<Option<Arc<(BlueprintTarget, Blueprint)>>>,
     nexus_label: String,
     tx: watch::Sender<usize>,
-    count: usize,
 }
 
 impl BlueprintExecutor {
@@ -33,7 +32,7 @@ impl BlueprintExecutor {
         nexus_label: String,
     ) -> BlueprintExecutor {
         let (tx, _) = watch::channel(0);
-        BlueprintExecutor { datastore, rx_blueprint, nexus_label, tx, count: 0 }
+        BlueprintExecutor { datastore, rx_blueprint, nexus_label, tx }
     }
 
     pub fn watcher(&self) -> watch::Receiver<usize> {
@@ -79,8 +78,7 @@ impl BackgroundTask for BlueprintExecutor {
             .await;
 
             // Trigger anybody waiting for this to finish.
-            self.count = self.count + 1;
-            self.tx.send(self.count);
+            self.tx.send_modify(|count| *count = *count + 1);
 
             // Return the result as a `serde_json::Value`
             match result {