APIServer: Add support for filtering to list rpc (#1175)

This is not intended to be used to support `--filter` or similar on the
CLIs list yet, it's solely to clean up our rather awkward use of
`ContainerClient.list()` today in the CLI. The list RPC simply returns
all of the containers we have created. Because of this, for a LOT of our
commands we filter to what we need client side, which feels like a
waste.. This change introduces a filter struct that we can provide an
array of container IDs, labels, and the status of the containers to
filter the `list()` output from.

This additionally, because it was killing (pun not intended) me and I
was already having to change this area for the `list()` additions,
changes container kill slightly to return an error if you try and kill a
container that doesn't exist.

Sources/Services/ContainerAPIService/Client/ContainerClient.swift

@@ -75,10 +75,12 @@ public struct ContainerClient: Sendable {
         }
     }
 
-    /// List all containers.
-    public func list() async throws -> [ContainerSnapshot] {
+    /// List containers matching the given filters.
+    public func list(filters: ContainerListFilters = .all) async throws -> [ContainerSnapshot] {
         do {
             let request = XPCMessage(route: .containerList)
+            let filterData = try JSONEncoder().encode(filters)
+            request.set(key: .listFilters, value: filterData)
 
             let response = try await xpcSend(
                 message: request,
@@ -100,8 +102,8 @@ public struct ContainerClient: Sendable {
 
     /// Get the container for the provided id.
     public func get(id: String) async throws -> ContainerSnapshot {
-        let containers = try await list()
-        guard let container = containers.first(where: { $0.configuration.id == id }) else {
+        let containers = try await list(filters: ContainerListFilters(ids: [id]))
+        guard let container = containers.first else {
             throw ContainerizationError(
                 .notFound,
                 message: "get failed: container \(id) not found"

Sources/Services/ContainerAPIService/Client/XPC+.swift

@@ -124,6 +124,9 @@ public enum XPCKeys: String {
     case statistics
     case containerSize
 
+    /// Container list filters
+    case listFilters
+
     /// Disk usage
     case diskUsageStats
 }

Sources/Services/ContainerAPIService/Server/Containers/ContainersHarness.swift

@@ -33,7 +33,11 @@ public struct ContainersHarness: Sendable {
 
     @Sendable
     public func list(_ message: XPCMessage) async throws -> XPCMessage {
-        let containers = try await service.list()
+        var filters = ContainerListFilters.all
+        if let filterData = message.dataNoCopy(key: .listFilters) {
+            filters = try JSONDecoder().decode(ContainerListFilters.self, from: filterData)
+        }
+        let containers = try await service.list(filters: filters)
         let data = try JSONEncoder().encode(containers)
 
         let reply = message.reply()

Sources/Services/ContainerAPIService/Server/Containers/ContainersService.swift

@@ -106,10 +106,33 @@ public actor ContainersService {
         return results
     }
 
-    /// List all containers registered with the service.
-    public func list() async throws -> [ContainerSnapshot] {
+    /// List containers matching the given filters.
+    public func list(filters: ContainerListFilters = .all) async throws -> [ContainerSnapshot] {
         self.log.debug("\(#function)")
-        return self.containers.values.map { $0.snapshot }
+
+        return self.containers.values.compactMap { state -> ContainerSnapshot? in
+            let snapshot = state.snapshot
+
+            if !filters.ids.isEmpty {
+                guard filters.ids.contains(snapshot.id) else {
+                    return nil
+                }
+            }
+
+            if let status = filters.status {
+                guard snapshot.status == status else {
+                    return nil
+                }
+            }
+
+            for (key, value) in filters.labels {
+                guard snapshot.configuration.labels[key] == value else {
+                    return nil
+                }
+            }
+
+            return snapshot
+        }
     }
 
     /// Execute an operation with the current container list while maintaining atomicity