Make UnstableReconfiguratorState::target_blueprint non-optional (#9423)

`UnstableReconfiguratorState`s constructed from real systems always
supplied a target blueprint, because real systems are required to always
have one. We'd kept this as optional to allow for `reconfigurator-cli`'s
simulated system to not have a blueprint at all, but I'd like to make
other changes related to the `PlanningInput` that trip over this
difference.

This PR addresses the simulator side by having it claim to have a
blueprint with the nil ID and containing nothing any time it's asked for
the current list of blueprints or current target blueprint and one
hasn't otherwise been set (i.e., by loading an example system or an
existing serialized state).

Author: jgallagher

dev-tools/omdb/src/bin/omdb/reconfigurator.rs

@@ -202,14 +202,7 @@ async fn cmd_reconfigurator_archive(
     //    successfully archived some blueprints before hitting this error. We
     //    attempt to notice this and log a message for the operator in this
     //    case.
-    let target_blueprint_id = saved_state
-        .target_blueprint
-        .context(
-            "system has no current target blueprint: \
-             cannot remove non-target blueprints",
-        )?
-        .target_id;
-
+    let target_blueprint_id = saved_state.target_blueprint.target_id;
     let mut ndeleted = 0;
 
     eprintln!("removing saved, non-target blueprints ...");

dev-tools/reconfigurator-cli/src/lib.rs

@@ -2121,12 +2121,12 @@ fn cmd_blueprint_list(
     let mut rows = state.system().all_blueprints().collect::<Vec<_>>();
     rows.sort_unstable_by_key(|blueprint| blueprint.time_created);
     let rows = rows.into_iter().map(|blueprint| {
-        let (is_target, enabled) = match target_blueprint {
-            Some(t) if t.target_id == blueprint.id => {
-                let enabled = if t.enabled { "yes" } else { "no" };
-                ("*", enabled)
-            }
-            _ => ("", ""),
+        let (is_target, enabled) = if target_blueprint.target_id == blueprint.id
+        {
+            let enabled = if target_blueprint.enabled { "yes" } else { "no" };
+            ("*", enabled)
+        } else {
+            ("", "")
         };
         BlueprintRow {
             is_target,

dev-tools/reconfigurator-cli/tests/output/cmds-stdout

@@ -11,7 +11,8 @@ ID SERIAL NZPOOLS SUBNET
 ID NERRORS TIME_DONE 
 
 > blueprint-list
-T ENA ID PARENT TIME_CREATED 
+T ENA ID                                   PARENT TIME_CREATED             
+* no  00000000-0000-0000-0000-000000000000 <none> <REDACTED_TIMESTAMP> 
 
 
 > sled-show dde1c0e2-b10d-4621-b420-f179f7a7a00a
@@ -863,14 +864,12 @@ wiped system
 
 > load state.json
 loaded data from "state.json"
-warnings:
-  could not determine active Nexus generation from serialized state: no target blueprint set (using default of 1)
 result:
   system:
     using collection 6e066695-94bc-4250-bd63-fd799c166cc1 as source of sled inventory data
     loaded sleds: 04ef3330-c682-4a08-8def-fcc4bef31bcd, 90c1102a-b9f5-4d88-92a2-60d54a2d98cc, dde1c0e2-b10d-4621-b420-f179f7a7a00a
     loaded collections: 6e066695-94bc-4250-bd63-fd799c166cc1
-    loaded blueprints: (none)
+    loaded blueprints: 00000000-0000-0000-0000-000000000000
     loaded external IP policy: ExternalIpPolicy { service_pool_ipv4_ranges: [Ipv4Range { first: 192.0.2.2, last: 192.0.2.20 }], service_pool_ipv6_ranges: [], external_dns_ips: {} }
     loaded internal DNS generations: (none)
     loaded external DNS generations: (none)

nexus/reconfigurator/preparation/src/lib.rs

@@ -582,7 +582,7 @@ pub async fn reconfigurator_state_load(
     Ok(UnstableReconfiguratorState {
         planning_input,
         collections,
-        target_blueprint: Some(target_blueprint),
+        target_blueprint,
         blueprints,
         internal_dns,
         external_dns,

nexus/reconfigurator/simulation/src/config.rs

@@ -166,7 +166,7 @@ impl SimConfigBuilder {
         external_dns_zone_names: Vec<String>,
         silo_names: Vec<Name>,
         active_nexus_zones: &BTreeSet<OmicronZoneUuid>,
-        target_blueprint: Option<&BlueprintTarget>,
+        target_blueprint: &BlueprintTarget,
         all_blueprints: &[Blueprint],
         res: &mut LoadSerializedResultBuilder,
     ) -> LoadSerializedConfigResult {
@@ -301,7 +301,7 @@ impl SimConfigBuilderInner {
         external_dns_zone_names: Vec<String>,
         silo_names: Vec<Name>,
         active_nexus_zones: &BTreeSet<OmicronZoneUuid>,
-        target_blueprint: Option<&BlueprintTarget>,
+        target_blueprint: &BlueprintTarget,
         all_blueprints: &[Blueprint],
         res: &mut LoadSerializedResultBuilder,
     ) -> LoadSerializedConfigResult {
@@ -403,12 +403,17 @@ impl SimConfigBuilderInner {
 
 fn determine_active_nexus_generation(
     active_nexus_zones: &BTreeSet<OmicronZoneUuid>,
-    target_blueprint: Option<&BlueprintTarget>,
+    target_blueprint: &BlueprintTarget,
     all_blueprints: &[Blueprint],
 ) -> Result<Generation, String> {
-    let Some(target_blueprint) = target_blueprint else {
-        return Err("no target blueprint set".to_string());
-    };
+    // Real systems always have at least one active Nexus zone, but our
+    // simulated system has some cases where we have none at all. We'll never be
+    // able to find the generation matching an empty set, but because this is a
+    // weird edge case that only applies to simulation, it's also fine to
+    // default to "the initial generation".
+    if active_nexus_zones.is_empty() {
+        return Ok(Generation::new());
+    }
 
     let Some(blueprint) =
         all_blueprints.iter().find(|bp| bp.id == target_blueprint.target_id)

nexus/reconfigurator/simulation/src/errors.rs

@@ -105,10 +105,6 @@ impl KeyError {
         Self { id: ObjectId::Collection(id) }
     }
 
-    pub(crate) fn blueprint(id: BlueprintId) -> Self {
-        Self { id: ObjectId::Blueprint(id) }
-    }
-
     pub(crate) fn resolved_collection(id: ResolvedCollectionId) -> Self {
         Self { id: ObjectId::ResolvedCollection(id) }
     }

nexus/reconfigurator/simulation/src/state.rs

@@ -237,7 +237,7 @@ impl SimStateBuilder {
             state.external_dns_zone_names.clone(),
             state.silo_names.clone(),
             state.planning_input.active_nexus_zones(),
-            state.target_blueprint.as_ref(),
+            &state.target_blueprint,
             &state.blueprints,
             &mut res,
         );