Add --dns support to build command for custom DNS resolution

Sources/ContainerCommands/BuildCommand.swift

@@ -125,6 +125,9 @@ extension Application {
         @OptionGroup
         public var logOptions: Flags.Logging
 
+        @OptionGroup
+        public var dns: Flags.DNS
+
         @Argument(help: "Build directory")
         var contextDir: String = "."
 
@@ -143,12 +146,13 @@ extension Application {
 
                 progress.set(description: "Dialing builder")
 
-                let builder: Builder? = try await withThrowingTaskGroup(of: Builder.self) { [vsockPort, cpus, memory] group in
+                let dnsNameservers = self.dns.nameservers
+                let builder: Builder? = try await withThrowingTaskGroup(of: Builder.self) { [vsockPort, cpus, memory, dnsNameservers] group in
                     defer {
                         group.cancelAll()
                     }
 
-                    group.addTask { [vsockPort, cpus, memory, log] in
+                    group.addTask { [vsockPort, cpus, memory, log, dnsNameservers] in
                         while true {
                             do {
                                 let container = try await ClientContainer.get(id: "buildkit")
@@ -170,6 +174,7 @@ extension Application {
                                     cpus: cpus,
                                     memory: memory,
                                     log: log,
+                                    dnsNameservers: dnsNameservers,
                                     progressUpdate: progress.handler
                                 )
 

Sources/ContainerCommands/Builder/BuilderStart.swift

@@ -45,6 +45,9 @@ extension Application {
         )
         var memory: String = "2048MB"
 
+        @OptionGroup
+        public var dns: Flags.DNS
+
         @OptionGroup
         public var logOptions: Flags.Logging
 
@@ -61,11 +64,29 @@ extension Application {
                 progress.finish()
             }
             progress.start()
-            try await Self.start(cpus: self.cpus, memory: self.memory, log: log, progressUpdate: progress.handler)
+            try await Self.start(
+                cpus: self.cpus,
+                memory: self.memory,
+                log: log,
+                dnsNameservers: self.dns.nameservers,
+                dnsDomain: self.dns.domain,
+                dnsSearchDomains: self.dns.searchDomains,
+                dnsOptions: self.dns.options,
+                progressUpdate: progress.handler
+            )
             progress.finish()
         }
 
-        static func start(cpus: Int64?, memory: String?, log: Logger, progressUpdate: @escaping ProgressUpdateHandler) async throws {
+        static func start(
+            cpus: Int64?,
+            memory: String?,
+            log: Logger,
+            dnsNameservers: [String] = [],
+            dnsDomain: String? = nil,
+            dnsSearchDomains: [String] = [],
+            dnsOptions: [String] = [],
+            progressUpdate: @escaping ProgressUpdateHandler
+        ) async throws {
             await progressUpdate([
                 .setDescription("Fetching BuildKit image"),
                 .setItemsName("blobs"),
@@ -103,6 +124,7 @@ extension Application {
                 let existingImage = existingContainer.configuration.image.reference
                 let existingResources = existingContainer.configuration.resources
                 let existingEnv = existingContainer.configuration.initProcess.environment
+                let existingDNS = existingContainer.configuration.dns
 
                 let existingManagedEnv = existingEnv.filter { envVar in
                     envVar.hasPrefix("BUILDKIT_COLORS=") || envVar.hasPrefix("NO_COLOR=")
@@ -129,11 +151,26 @@ extension Application {
                     }
                     return false
                 }()
+                let dnsChanged = {
+                    if !dnsNameservers.isEmpty {
+                        return existingDNS?.nameservers != dnsNameservers
+                    }
+                    if dnsDomain != nil {
+                        return existingDNS?.domain != dnsDomain
+                    }
+                    if !dnsSearchDomains.isEmpty {
+                        return existingDNS?.searchDomains != dnsSearchDomains
+                    }
+                    if !dnsOptions.isEmpty {
+                        return existingDNS?.options != dnsOptions
+                    }
+                    return false
+                }()
 
                 switch existingContainer.status {
                 case .running:
-                    guard imageChanged || cpuChanged || memChanged || envChanged else {
-                        // If image, mem and cpu are the same, continue using the existing builder
+                    guard imageChanged || cpuChanged || memChanged || envChanged || dnsChanged else {
+                        // If image, mem, cpu, env, and DNS are the same, continue using the existing builder
                         return
                     }
                     // If they changed, stop and delete the existing builder
@@ -142,7 +179,7 @@ extension Application {
                 case .stopped:
                     // If the builder is stopped and matches our requirements, start it
                     // Otherwise, delete it and create a new one
-                    guard imageChanged || cpuChanged || memChanged || envChanged else {
+                    guard imageChanged || cpuChanged || memChanged || envChanged || dnsChanged else {
                         try await existingContainer.startBuildKit(progressUpdate, nil)
                         return
                     }
@@ -233,8 +270,13 @@ extension Application {
             config.networks = [AttachmentConfiguration(network: network.id, options: AttachmentOptions(hostname: id))]
             let subnet = networkStatus.ipv4Subnet
             let nameserver = IPv4Address(subnet.lower.value + 1).description
-            let nameservers = [nameserver]
-            config.dns = ContainerConfiguration.DNSConfiguration(nameservers: nameservers)
+            let nameservers = dnsNameservers.isEmpty ? [nameserver] : dnsNameservers
+            config.dns = ContainerConfiguration.DNSConfiguration(
+                nameservers: nameservers,
+                domain: dnsDomain,
+                searchDomains: dnsSearchDomains,
+                options: dnsOptions
+            )
 
             let kernel = try await {
                 await progressUpdate([

Sources/Services/ContainerAPIService/Client/Flags.swift

@@ -76,6 +76,34 @@ public struct Flags {
         public var memory: String?
     }
 
+    public struct DNS: ParsableArguments {
+        public init() {}
+
+        @Option(
+            name: .customLong("dns"),
+            help: .init("DNS nameserver IP address", valueName: "ip")
+        )
+        public var nameservers: [String] = []
+
+        @Option(
+            name: .customLong("dns-domain"),
+            help: .init("Default DNS domain", valueName: "domain")
+        )
+        public var domain: String? = nil
+
+        @Option(
+            name: .customLong("dns-option"),
+            help: .init("DNS options", valueName: "option")
+        )
+        public var options: [String] = []
+
+        @Option(
+            name: .customLong("dns-search"),
+            help: .init("DNS search domains", valueName: "domain")
+        )
+        public var searchDomains: [String] = []
+    }
+
     public struct Registry: ParsableArguments {
         public init() {}
 
@@ -99,29 +127,8 @@ public struct Flags {
         @Flag(name: .shortAndLong, help: "Run the container and detach from the process")
         public var detach = false
 
-        @Option(
-            name: .customLong("dns"),
-            help: .init("DNS nameserver IP address", valueName: "ip")
-        )
-        public var dnsNameservers: [String] = []
-
-        @Option(
-            name: .long,
-            help: .init("Default DNS domain", valueName: "domain")
-        )
-        public var dnsDomain: String? = nil
-
-        @Option(
-            name: .customLong("dns-option"),
-            help: .init("DNS options", valueName: "option")
-        )
-        public var dnsOptions: [String] = []
-
-        @Option(
-            name: .customLong("dns-search"),
-            help: .init("DNS search domains", valueName: "domain")
-        )
-        public var dnsSearchDomains: [String] = []
+        @OptionGroup
+        public var dns: Flags.DNS
 
         @Option(
             name: .long,

Sources/Services/ContainerAPIService/Client/Utility.swift

@@ -209,12 +209,12 @@ public struct Utility {
         if management.dnsDisabled {
             config.dns = nil
         } else {
-            let domain = management.dnsDomain ?? DefaultsStore.getOptional(key: .defaultDNSDomain)
+            let domain = management.dns.domain ?? DefaultsStore.getOptional(key: .defaultDNSDomain)
             config.dns = .init(
-                nameservers: management.dnsNameservers,
+                nameservers: management.dns.nameservers,
                 domain: domain,
-                searchDomains: management.dnsSearchDomains,
-                options: management.dnsOptions
+                searchDomains: management.dns.searchDomains,
+                options: management.dns.options
             )
         }