Add database layer for assigning an IP Pool to a service

- Add an enum for external networking services.
- Add a join table for associating `ip_pool` records with specific
  services.
- Add datastore methods for assigning / unassigning, with a bunch of
  tests.
- The join table is empty and the datastore methods aren't consumed.
  This is all plumbing work, to support the planned Nexus API for
  operators and letting Reconfigurator read the pools it should use to
  plan external addresses for its zones.

Author: bnaecker

nexus/db-model/src/external_service_ip_pool.rs

@@ -0,0 +1,64 @@
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at https://mozilla.org/MPL/2.0/.
+
+//! Model types for assigning IP pools to individual external services.
+
+use super::impl_enum_type;
+use diesel::Insertable;
+use diesel::Queryable;
+use diesel::Selectable;
+use nexus_db_schema::schema::external_service_ip_pool;
+use serde::Deserialize;
+use serde::Serialize;
+use uuid::Uuid;
+
+impl_enum_type!(
+    ExternalServiceKindEnum:
+
+    #[derive(
+        Copy,
+        Clone,
+        Debug,
+        PartialEq,
+        Eq,
+        Serialize,
+        Deserialize,
+        AsExpression,
+        FromSqlRow,
+    )]
+    #[serde(rename_all = "snake_case")]
+    pub enum ExternalServiceKind;
+
+    Nexus => b"nexus"
+    BoundaryNtp => b"boundary_ntp"
+    ExternalDns => b"external_dns"
+);
+
+impl std::fmt::Display for ExternalServiceKind {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        let s = match self {
+            ExternalServiceKind::Nexus => "nexus",
+            ExternalServiceKind::BoundaryNtp => "boundary_ntp",
+            ExternalServiceKind::ExternalDns => "external_dns",
+        };
+        f.write_str(s)
+    }
+}
+
+/// Assignment of an IP pool to an external service (Nexus or boundary NTP).
+//
+// NOTE: The associations here intentionally avoid any semantics like
+// exclusivity or what an assignment means for the application. Each service
+// could be different in that respect, and we haven't really fleshed out enough
+// of the system to know how to use the records here. For now, we just enforce
+// basic sanity checks, like that operators cannot delete the last pool assigned
+// to a service, or concurrent operations on the pool and this record.
+#[derive(
+    Queryable, Clone, Copy, Debug, PartialEq, Eq, Selectable, Insertable,
+)]
+#[diesel(table_name = external_service_ip_pool)]
+pub struct ExternalServiceIpPool {
+    pub service: ExternalServiceKind,
+    pub ip_pool_id: Uuid,
+}

nexus/db-model/src/lib.rs

@@ -151,6 +151,7 @@ pub mod ereport;
 mod ereporter_restart;
 mod ereporter_type;
 mod external_ip;
+mod external_service_ip_pool;
 mod external_subnet;
 pub mod fm;
 mod generation;
@@ -305,6 +306,7 @@ pub use ereport::Ereport;
 pub use ereporter_restart::*;
 pub use ereporter_type::*;
 pub use external_ip::*;
+pub use external_service_ip_pool::*;
 pub use external_subnet::*;
 pub use fm::{SitrepMetadata, SitrepVersion};
 pub use generation::*;

nexus/db-model/src/schema_versions.rs

@@ -16,7 +16,7 @@ use std::{collections::BTreeMap, sync::LazyLock};
 ///
 /// This must be updated when you change the database schema.  Refer to
 /// schema/crdb/README.adoc in the root of this repository for details.
-pub const SCHEMA_VERSION: Version = Version::new(291, 0, 0);
+pub const SCHEMA_VERSION: Version = Version::new(292, 0, 0);
 
 /// List of all past database schema versions, in *reverse* order
 ///
@@ -28,6 +28,7 @@ pub static KNOWN_VERSIONS: LazyLock<Vec<KnownVersion>> = LazyLock::new(|| {
         // |  leaving the first copy as an example for the next person.
         // v
         // KnownVersion::new(next_int, "unique-dirname-with-the-sql-files"),
+        KnownVersion::new(292, "external-service-ip-pool"),
         KnownVersion::new(291, "bgp-peer-src-addr"),
         KnownVersion::new(290, "saga-abandon-reason-orphaned"),
         KnownVersion::new(289, "normalize-service-external-ips"),