Merge pull request #1373 from LukasKorba/1153-Allow-runtime-switch-of-lightwalletd-servers

[#1153] Allow runtime switch of lightwalletd servers

CHANGELOG.md

@@ -11,6 +11,14 @@ and this library adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### [#1363] Account balances in the SynchronizerState
 `shieldedBalance: WalletBalance` has been replaced with `accountBalances: AccountBalance`. `AccountBalance` provides the same values as `shieldedBalance` but adds up a pending changes. Under the hood this calls rust's `getWalletSummary` which improved also the syncing initial values of % and balances.
 
+## Added
+
+### [#1153] Allow runtime switch of lightwalletd servers
+New API implemented that allows clients to change the `mainnet` endpoint. Use `func switchTo(endpoint: LightWalletEndpoint) async throws`. 
+Possible errors:
+- `ZcashError.synchronizerServerSwitch`: endpoint fails, check the address, port and format address:port,
+- Some `ZcashError` related to `synchronizer.Start()`: the switch calls `start()` at the end and that is the only throwing function except the validation.
+
 # 2.0.8 - 2024-01-30
 
 Adopt `zcash-light-client-ffi 0.5.1`. This fixes a serialization problem 

Example/ZcashLightClientSample/ZcashLightClientSample/Base.lproj/Main.storyboard

@@ -1,9 +1,9 @@
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     <dependencies>
         <deployment identifier="iOS"/>
-        <plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="21679"/>
+        <plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="22504"/>
         <capability name="Safe area layout guides" minToolsVersion="9.0"/>
         <capability name="System colors in document resources" minToolsVersion="11.0"/>
         <capability name="documents saved in the Xcode 8 format" minToolsVersion="8.0"/>
@@ -959,16 +959,16 @@
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@@ -979,28 +979,28 @@
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                                     </stackView>
                                     <label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" ambiguous="YES" text="Progress" textAlignment="center" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="JPx-ol-2nc">
-                                        <rect key="frame" x="0.0" y="280.33333333333331" width="366" height="43"/>
+                                        <rect key="frame" x="0.0" y="343" width="366" height="43"/>
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+                                        <rect key="frame" x="0.0" y="410" width="366" height="2.6666666666666856"/>
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                                     <label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" ambiguous="YES" text="0%" textAlignment="center" lineBreakMode="tailTruncation" numberOfLines="0" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="kXE-5z-HN2">
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+                                        <rect key="frame" x="0.0" y="435.66666666666663" width="374" height="39.666666666666686"/>
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                                     <label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" ambiguous="YES" text="" lineBreakMode="tailTruncation" numberOfLines="0" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="x3B-hR-coo" userLabel="ProgressDataLabel">
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                                         <state key="normal" title="Start"/>
                                         <connections>
@@ -1008,19 +1008,19 @@
                                         </connections>
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                                     <label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" ambiguous="YES" text="Label" textAlignment="natural" lineBreakMode="tailTruncation" numberOfLines="0" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="XK2-GA-Ufv">
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@@ -1399,7 +1399,7 @@
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         <systemColor name="labelColor">
-            <color red="0.0" green="0.0" blue="0.0" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
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@@ -1408,10 +1408,10 @@
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         </systemColor>
         <systemColor name="systemGray2Color">
-            <color red="0.68235294117647061" green="0.68235294117647061" blue="0.69803921568627447" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
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         </systemColor>
         <systemColor name="systemRedColor">
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+            <color red="1" green="0.23137254900000001" blue="0.18823529410000001" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
         </systemColor>
     </resources>
 </document>

Example/ZcashLightClientSample/ZcashLightClientSample/DemoAppConfig.swift

@@ -21,15 +21,15 @@ enum DemoAppConfig {
     static let host = ZcashSDK.isMainnet ? "mainnet.lightwalletd.com" : "lightwalletd.testnet.electriccoin.co"
     static let port: Int = 9067
 
-//    static let defaultBirthdayHeight: BlockHeight = ZcashSDK.isMainnet ? 935000 : 1386000
+    static let defaultBirthdayHeight: BlockHeight = ZcashSDK.isMainnet ? 935000 : 1386000
-//    static let defaultSeed = try! Mnemonic.deterministicSeedBytes(from: """
+
-//    live combine flight accident slow soda mind bright absent bid hen shy decade biology amazing mix enlist ensure biology rhythm snap duty soap armor
+//    static let defaultSeed = try! Mnemonic.deterministicSeedBytes(from: """
-//    """)
+//        wish puppy smile loan doll curve hole maze file ginger hair nose key relax knife witness cannon grab despair throw review deal slush frame
+//        """)
 
-    static let defaultBirthdayHeight: BlockHeight = ZcashSDK.isMainnet ? 1935000 : 2170000
     static let defaultSeed = try! Mnemonic.deterministicSeedBytes(from: """
-    wish puppy smile loan doll curve hole maze file ginger hair nose key relax knife witness cannon grab despair throw review deal slush frame
+        live combine flight accident slow soda mind bright absent bid hen shy decade biology amazing mix enlist ensure biology rhythm snap duty soap armor
-    """)
+        """)
 
     static let otherSynchronizers: [SynchronizerInitData] = [
         SynchronizerInitData(
@@ -53,7 +53,7 @@ enum DemoAppConfig {
     static var address: String {
         "\(host):\(port)"
     }
-    
+
     static var endpoint: LightWalletEndpoint {
         return LightWalletEndpoint(address: self.host, port: self.port, secure: true, streamingCallTimeoutInMillis: 10 * 60 * 60 * 1000)
     }

Sources/ZcashLightClientKit/Block/Actions/DownloadAction.swift

@@ -9,7 +9,7 @@ import Foundation
 
 final class DownloadAction {
     let configProvider: CompactBlockProcessor.ConfigProvider
-    let downloader: BlockDownloader
+    var downloader: BlockDownloader
     let transactionRepository: TransactionRepository
     let logger: Logger
 

Sources/ZcashLightClientKit/Block/Actions/EnhanceAction.swift

@@ -8,7 +8,7 @@
 import Foundation
 
 final class EnhanceAction {
-    let blockEnhancer: BlockEnhancer
+    var blockEnhancer: BlockEnhancer
     let configProvider: CompactBlockProcessor.ConfigProvider
     let logger: Logger
     

Sources/ZcashLightClientKit/Block/Actions/FetchUTXOsAction.swift

@@ -8,7 +8,7 @@
 import Foundation
 
 final class FetchUTXOsAction {
-    let utxoFetcher: UTXOFetcher
+    var utxoFetcher: UTXOFetcher
     let logger: Logger
 
     init(container: DIContainer) {

Sources/ZcashLightClientKit/Block/Actions/ProcessSuggestedScanRangesAction.swift

@@ -9,7 +9,7 @@ import Foundation
 
 final class ProcessSuggestedScanRangesAction {
     let rustBackend: ZcashRustBackendWelding
-    let service: LightWalletService
+    var service: LightWalletService
     let logger: Logger
     let metrics: SDKMetrics
     

Sources/ZcashLightClientKit/Block/Actions/RewindAction.swift

@@ -8,9 +8,9 @@
 import Foundation
 
 final class RewindAction {
-    let downloader: BlockDownloader
+    var downloader: BlockDownloader
     let rustBackend: ZcashRustBackendWelding
-    let downloaderService: BlockDownloaderService
+    var downloaderService: BlockDownloaderService
     let logger: Logger
 
     init(container: DIContainer) {

Sources/ZcashLightClientKit/Block/Actions/ScanAction.swift

@@ -15,7 +15,7 @@ final class ScanAction {
     let configProvider: CompactBlockProcessor.ConfigProvider
     let blockScanner: BlockScanner
     let rustBackend: ZcashRustBackendWelding
-    let latestBlocksDataProvider: LatestBlocksDataProvider
+    var latestBlocksDataProvider: LatestBlocksDataProvider
     let logger: Logger
     var progressReportReducer = 0
 

Sources/ZcashLightClientKit/Block/Actions/UpdateChainTipAction.swift

@@ -9,9 +9,9 @@ import Foundation
 
 final class UpdateChainTipAction {
     let rustBackend: ZcashRustBackendWelding
-    let downloader: BlockDownloader
+    var downloader: BlockDownloader
-    let service: LightWalletService
+    var service: LightWalletService
-    let latestBlocksDataProvider: LatestBlocksDataProvider
+    var latestBlocksDataProvider: LatestBlocksDataProvider
     let logger: Logger
     
     init(container: DIContainer) {

Sources/ZcashLightClientKit/Block/Actions/UpdateSubtreeRootsAction.swift

@@ -10,7 +10,7 @@ import Foundation
 final class UpdateSubtreeRootsAction {
     let configProvider: CompactBlockProcessor.ConfigProvider
     let rustBackend: ZcashRustBackendWelding
-    let service: LightWalletService
+    var service: LightWalletService
     let logger: Logger
     
     init(container: DIContainer, configProvider: CompactBlockProcessor.ConfigProvider) {

Sources/ZcashLightClientKit/Block/Actions/ValidateServerAction.swift

@@ -10,7 +10,7 @@ import Foundation
 final class ValidateServerAction {
     let configProvider: CompactBlockProcessor.ConfigProvider
     let rustBackend: ZcashRustBackendWelding
-    let service: LightWalletService
+    var service: LightWalletService
 
     init(container: DIContainer, configProvider: CompactBlockProcessor.ConfigProvider) {
         self.configProvider = configProvider

Sources/ZcashLightClientKit/Block/CompactBlockProcessor.swift

@@ -29,12 +29,12 @@ actor CompactBlockProcessor {
     private var afterSyncHooksManager = AfterSyncHooksManager()
 
     private let accountRepository: AccountRepository
-    let blockDownloaderService: BlockDownloaderService
+    var blockDownloaderService: BlockDownloaderService
-    private let latestBlocksDataProvider: LatestBlocksDataProvider
+    private var latestBlocksDataProvider: LatestBlocksDataProvider
     private let logger: Logger
     private let metrics: SDKMetrics
     private let rustBackend: ZcashRustBackendWelding
-    let service: LightWalletService
+    var service: LightWalletService
     let storage: CompactBlockRepository
     private let transactionRepository: TransactionRepository
     private let fileManager: ZcashFileManager
@@ -412,6 +412,52 @@ extension CompactBlockProcessor {
     }
 }
 
+// MARK: - Switch server
+
+extension CompactBlockProcessor {
+    func updateService(_ container: DIContainer) {
+        // LightWalletGRPCService
+        let updatedLWDService = container.resolve(LightWalletService.self)
+        
+        (actions[.processSuggestedScanRanges] as? ProcessSuggestedScanRangesAction)?.service = updatedLWDService
+        (actions[.updateChainTip] as? UpdateChainTipAction)?.service = updatedLWDService
+        (actions[.updateSubtreeRoots] as? UpdateSubtreeRootsAction)?.service = updatedLWDService
+        (actions[.validateServer] as? ValidateServerAction)?.service = updatedLWDService
+        self.service = updatedLWDService
+        
+        // BlockDownloaderService
+        let updatedDownloaderService = container.resolve(BlockDownloaderService.self)
+
+        (actions[.rewind] as? RewindAction)?.downloaderService = updatedDownloaderService
+        self.blockDownloaderService = updatedDownloaderService
+        
+        // LatestBlocksDataProvider
+        let updatedLBDProvider = container.resolve(LatestBlocksDataProvider.self)
+
+        (actions[.scan] as? ScanAction)?.latestBlocksDataProvider = updatedLBDProvider
+        (actions[.updateChainTip] as? UpdateChainTipAction)?.latestBlocksDataProvider = updatedLBDProvider
+        self.latestBlocksDataProvider = updatedLBDProvider
+        
+        // BlockDownloader
+        let updatedBlockDownloader = container.resolve(BlockDownloader.self)
+
+        (actions[.download] as? DownloadAction)?.downloader = updatedBlockDownloader
+        (actions[.updateChainTip] as? UpdateChainTipAction)?.downloader = updatedBlockDownloader
+        (actions[.rewind] as? RewindAction)?.downloader = updatedBlockDownloader
+        self.blockDownloaderService = updatedDownloaderService
+        
+        // BlockEnhancer
+        let updatedEnhancer = container.resolve(BlockEnhancer.self)
+
+        (actions[.enhance] as? EnhanceAction)?.blockEnhancer = updatedEnhancer
+
+        // UTXOFetcher
+        let updatedUTXOFetcher = container.resolve(UTXOFetcher.self)
+
+        (actions[.fetchUTXO] as? FetchUTXOsAction)?.utxoFetcher = updatedUTXOFetcher
+    }
+}
+
 // MARK: - Events
 
 extension CompactBlockProcessor {

Sources/ZcashLightClientKit/Error/Sourcery/generateErrorCode.sh

@@ -3,7 +3,7 @@
 scriptDir=${0:a:h}
 cd "${scriptDir}"
 
-sourcery_version=2.0.3
+sourcery_version=2.1.7
 
 if which sourcery >/dev/null; then
     if [[ $(sourcery --version) != $sourcery_version ]]; then

Sources/ZcashLightClientKit/Error/ZcashError.swift

@@ -1,4 +1,4 @@
-// Generated using Sourcery 2.0.3 — https://github.com/krzysztofzablocki/Sourcery
+// Generated using Sourcery 2.1.7 — https://github.com/krzysztofzablocki/Sourcery
 // DO NOT EDIT
 
 /*
@@ -121,6 +121,11 @@ public enum ZcashError: Equatable, Error {
     /// - `rustError` contains error generated by the rust layer.
     /// ZRUST0003
     case rustDecryptAndStoreTransaction(_ rustError: String)
+    /// Error from rust layer when calling ZcashRustBackend.getBalance
+    /// - `account` is account passed to ZcashRustBackend.getBalance.
+    /// - `rustError` contains error generated by the rust layer.
+    /// ZRUST0004
+    case rustGetBalance(_ account: Int, _ rustError: String)
     /// Error from rust layer when calling ZcashRustBackend.getCurrentAddress
     /// - `rustError` contains error generated by the rust layer.
     /// ZRUST0005
@@ -148,6 +153,11 @@ public enum ZcashError: Equatable, Error {
     /// - `rustError` contains error generated by the rust layer.
     /// ZRUST0011
     case rustGetTransparentBalance(_ account: Int, _ rustError: String)
+    /// Error from rust layer when calling ZcashRustBackend.getVerifiedBalance
+    /// - `account` is account passed to ZcashRustBackend.getVerifiedBalance.
+    /// - `rustError` contains error generated by the rust layer.
+    /// ZRUST0012
+    case rustGetVerifiedBalance(_ account: Int, _ rustError: String)
     /// account parameter is lower than 0 when calling ZcashRustBackend.getVerifiedTransparentBalance
     /// - `account` is account passed to ZcashRustBackend.getVerifiedTransparentBalance.
     /// ZRUST0013
@@ -287,6 +297,10 @@ public enum ZcashError: Equatable, Error {
     /// Invalid transaction ID length when calling ZcashRustBackend.getMemo. txId must be 32 bytes.
     /// ZRUST0050
     case rustGetMemoInvalidTxIdLength
+    /// Error from rust layer when calling ZcashRustBackend.getScanProgress
+    /// - `rustError` contains error generated by the rust layer.
+    /// ZRUST0051
+    case rustGetScanProgress(_ rustError: String)
     /// Error from rust layer when calling ZcashRustBackend.fullyScannedHeight
     /// - `rustError` contains error generated by the rust layer.
     /// ZRUST0052
@@ -570,6 +584,9 @@ public enum ZcashError: Equatable, Error {
     /// Indicates that this Synchronizer is disconnected from its lightwalletd server.
     /// ZSYNCO0006
     case synchronizerDisconnected
+    /// The attempt to switch endpoints failed. Check that the hostname and port are correct, and are formatted as <hostname>:<port>.
+    /// ZSYNCO0007
+    case synchronizerServerSwitch
 
     public var message: String {
         switch self {
@@ -604,6 +621,7 @@ public enum ZcashError: Equatable, Error {
         case .rustCreateAccount: return "Error from rust layer when calling ZcashRustBackend.createAccount"
         case .rustCreateToAddress: return "Error from rust layer when calling ZcashRustBackend.createToAddress"
         case .rustDecryptAndStoreTransaction: return "Error from rust layer when calling ZcashRustBackend.decryptAndStoreTransaction"
+        case .rustGetBalance: return "Error from rust layer when calling ZcashRustBackend.getBalance"
         case .rustGetCurrentAddress: return "Error from rust layer when calling ZcashRustBackend.getCurrentAddress"
         case .rustGetCurrentAddressInvalidAddress: return "Unified address generated by rust layer is invalid when calling ZcashRustBackend.getCurrentAddress"
         case .rustGetNearestRewindHeight: return "Error from rust layer when calling ZcashRustBackend.getNearestRewindHeight"
@@ -611,6 +629,7 @@ public enum ZcashError: Equatable, Error {
         case .rustGetNextAvailableAddressInvalidAddress: return "Unified address generated by rust layer is invalid when calling ZcashRustBackend.getNextAvailableAddress"
         case .rustGetTransparentBalanceNegativeAccount: return "account parameter is lower than 0 when calling ZcashRustBackend.getTransparentBalance"
         case .rustGetTransparentBalance: return "Error from rust layer when calling ZcashRustBackend.getTransparentBalance"
+        case .rustGetVerifiedBalance: return "Error from rust layer when calling ZcashRustBackend.getVerifiedBalance"
         case .rustGetVerifiedTransparentBalanceNegativeAccount: return "account parameter is lower than 0 when calling ZcashRustBackend.getVerifiedTransparentBalance"
         case .rustGetVerifiedTransparentBalance: return "Error from rust layer when calling ZcashRustBackend.getVerifiedTransparentBalance"
         case .rustInitDataDb: return "Error from rust layer when calling ZcashRustBackend.initDataDb"
@@ -648,6 +667,7 @@ public enum ZcashError: Equatable, Error {
         case .rustUpdateChainTip: return "Error from rust layer when calling ZcashRustBackend.updateChainTip"
         case .rustSuggestScanRanges: return "Error from rust layer when calling ZcashRustBackend.suggestScanRanges"
         case .rustGetMemoInvalidTxIdLength: return "Invalid transaction ID length when calling ZcashRustBackend.getMemo. txId must be 32 bytes."
+        case .rustGetScanProgress: return "Error from rust layer when calling ZcashRustBackend.getScanProgress"
         case .rustFullyScannedHeight: return "Error from rust layer when calling ZcashRustBackend.fullyScannedHeight"
         case .rustMaxScannedHeight: return "Error from rust layer when calling ZcashRustBackend.maxScannedHeight"
         case .rustLatestCachedBlockHeight: return "Error from rust layer when calling ZcashRustBackend.latestCachedBlockHeight"
@@ -737,6 +757,7 @@ public enum ZcashError: Equatable, Error {
         case .synchronizerLatestUTXOsInvalidTAddress: return "LatestUTXOs for the address failed, invalid t-address."
         case .synchronizerRewindUnknownArchorHeight: return "Rewind failed, unknown archor height"
         case .synchronizerDisconnected: return "Indicates that this Synchronizer is disconnected from its lightwalletd server."
+        case .synchronizerServerSwitch: return "The attempt to switch endpoints failed. Check that the hostname and port are correct, and are formatted as <hostname>:<port>."
         }
     }
 
@@ -773,6 +794,7 @@ public enum ZcashError: Equatable, Error {
         case .rustCreateAccount: return .rustCreateAccount
         case .rustCreateToAddress: return .rustCreateToAddress
         case .rustDecryptAndStoreTransaction: return .rustDecryptAndStoreTransaction
+        case .rustGetBalance: return .rustGetBalance
         case .rustGetCurrentAddress: return .rustGetCurrentAddress
         case .rustGetCurrentAddressInvalidAddress: return .rustGetCurrentAddressInvalidAddress
         case .rustGetNearestRewindHeight: return .rustGetNearestRewindHeight
@@ -780,6 +802,7 @@ public enum ZcashError: Equatable, Error {
         case .rustGetNextAvailableAddressInvalidAddress: return .rustGetNextAvailableAddressInvalidAddress
         case .rustGetTransparentBalanceNegativeAccount: return .rustGetTransparentBalanceNegativeAccount
         case .rustGetTransparentBalance: return .rustGetTransparentBalance
+        case .rustGetVerifiedBalance: return .rustGetVerifiedBalance
         case .rustGetVerifiedTransparentBalanceNegativeAccount: return .rustGetVerifiedTransparentBalanceNegativeAccount
         case .rustGetVerifiedTransparentBalance: return .rustGetVerifiedTransparentBalance
         case .rustInitDataDb: return .rustInitDataDb
@@ -817,6 +840,7 @@ public enum ZcashError: Equatable, Error {
         case .rustUpdateChainTip: return .rustUpdateChainTip
         case .rustSuggestScanRanges: return .rustSuggestScanRanges
         case .rustGetMemoInvalidTxIdLength: return .rustGetMemoInvalidTxIdLength
+        case .rustGetScanProgress: return .rustGetScanProgress
         case .rustFullyScannedHeight: return .rustFullyScannedHeight
         case .rustMaxScannedHeight: return .rustMaxScannedHeight
         case .rustLatestCachedBlockHeight: return .rustLatestCachedBlockHeight
@@ -906,6 +930,7 @@ public enum ZcashError: Equatable, Error {
         case .synchronizerLatestUTXOsInvalidTAddress: return .synchronizerLatestUTXOsInvalidTAddress
         case .synchronizerRewindUnknownArchorHeight: return .synchronizerRewindUnknownArchorHeight
         case .synchronizerDisconnected: return .synchronizerDisconnected
+        case .synchronizerServerSwitch: return .synchronizerServerSwitch
         }
     }
 

Sources/ZcashLightClientKit/Error/ZcashErrorCode.swift

@@ -1,4 +1,4 @@
-// Generated using Sourcery 2.0.3 — https://github.com/krzysztofzablocki/Sourcery
+// Generated using Sourcery 2.1.7 — https://github.com/krzysztofzablocki/Sourcery
 // DO NOT EDIT
 
 /*
@@ -71,6 +71,8 @@ public enum ZcashErrorCode: String {
     case rustCreateToAddress = "ZRUST0002"
     /// Error from rust layer when calling ZcashRustBackend.decryptAndStoreTransaction
     case rustDecryptAndStoreTransaction = "ZRUST0003"
+    /// Error from rust layer when calling ZcashRustBackend.getBalance
+    case rustGetBalance = "ZRUST0004"
     /// Error from rust layer when calling ZcashRustBackend.getCurrentAddress
     case rustGetCurrentAddress = "ZRUST0005"
     /// Unified address generated by rust layer is invalid when calling ZcashRustBackend.getCurrentAddress
@@ -85,6 +87,8 @@ public enum ZcashErrorCode: String {
     case rustGetTransparentBalanceNegativeAccount = "ZRUST0010"
     /// Error from rust layer when calling ZcashRustBackend.getTransparentBalance
     case rustGetTransparentBalance = "ZRUST0011"
+    /// Error from rust layer when calling ZcashRustBackend.getVerifiedBalance
+    case rustGetVerifiedBalance = "ZRUST0012"
     /// account parameter is lower than 0 when calling ZcashRustBackend.getVerifiedTransparentBalance
     case rustGetVerifiedTransparentBalanceNegativeAccount = "ZRUST0013"
     /// Error from rust layer when calling ZcashRustBackend.getVerifiedTransparentBalance
@@ -159,6 +163,8 @@ public enum ZcashErrorCode: String {
     case rustSuggestScanRanges = "ZRUST0049"
     /// Invalid transaction ID length when calling ZcashRustBackend.getMemo. txId must be 32 bytes.
     case rustGetMemoInvalidTxIdLength = "ZRUST0050"
+    /// Error from rust layer when calling ZcashRustBackend.getScanProgress
+    case rustGetScanProgress = "ZRUST0051"
     /// Error from rust layer when calling ZcashRustBackend.fullyScannedHeight
     case rustFullyScannedHeight = "ZRUST0052"
     /// Error from rust layer when calling ZcashRustBackend.maxScannedHeight
@@ -337,4 +343,6 @@ public enum ZcashErrorCode: String {
     case synchronizerRewindUnknownArchorHeight = "ZSYNCO0005"
     /// Indicates that this Synchronizer is disconnected from its lightwalletd server.
     case synchronizerDisconnected = "ZSYNCO0006"
+    /// The attempt to switch endpoints failed. Check that the hostname and port are correct, and are formatted as <hostname>:<port>.
+    case synchronizerServerSwitch = "ZSYNCO0007"
 }

Sources/ZcashLightClientKit/Error/ZcashErrorCodeDefinition.swift

@@ -344,7 +344,11 @@ enum ZcashErrorDefinition {
     /// - `progress` value reported
     // sourcery: code="ZRUST0055"
     case rustScanProgressOutOfRange(_ progress: String)
-
+    /// Error from rust layer when calling ZcashRustBackend.getWalletSummary
+    /// - `rustError` contains error generated by the rust layer.
+    // sourcery: code="ZRUST0056"
+    case rustGetWalletSummary(_ rustError: String)
+    
     // MARK: - Account DAO
 
     /// SQLite query failed when fetching all accounts from the database.
@@ -659,4 +663,7 @@ enum ZcashErrorDefinition {
     /// Indicates that this Synchronizer is disconnected from its lightwalletd server.
     // sourcery: code="ZSYNCO0006"
     case synchronizerDisconnected
+    /// The attempt to switch endpoints failed. Check that the hostname and port are correct, and are formatted as <hostname>:<port>.
+    // sourcery: code="ZSYNCO0007"
+    case synchronizerServerSwitch
 }

Sources/ZcashLightClientKit/Initializer.swift

@@ -111,18 +111,18 @@ public class Initializer {
 
     let container: DIContainer
     let alias: ZcashSynchronizerAlias
-    let endpoint: LightWalletEndpoint
+    var endpoint: LightWalletEndpoint
     let fsBlockDbRoot: URL
     let generalStorageURL: URL
     let dataDbURL: URL
     let spendParamsURL: URL
     let outputParamsURL: URL
     let saplingParamsSourceURL: SaplingParamsSourceURL
-    let lightWalletService: LightWalletService
+    var lightWalletService: LightWalletService
     let transactionRepository: TransactionRepository
     let accountRepository: AccountRepository
     let storage: CompactBlockRepository
-    let blockDownloaderService: BlockDownloaderService
+    var blockDownloaderService: BlockDownloaderService
     let network: ZcashNetwork
     let logger: Logger
     let rustBackend: ZcashRustBackendWelding
@@ -286,10 +286,6 @@ public class Initializer {
         self.logger = container.resolve(Logger.self)
     }
     
-    private static func makeLightWalletServiceFactory(endpoint: LightWalletEndpoint) -> LightWalletServiceFactory {
-        return LightWalletServiceFactory(endpoint: endpoint)
-    }
-    
     // swiftlint:disable:next function_parameter_count
     private static func setup(
         container: DIContainer,

Sources/ZcashLightClientKit/Synchronizer.swift

@@ -295,6 +295,12 @@ public protocol Synchronizer: AnyObject {
     /// this happens it means that some path passed to `Initializer` is invalid. The SDK can't recover from this and this instance won't do anything.
     /// 
     func wipe() -> AnyPublisher<Void, Error>
+    
+    /// This API stops the synchronization and re-initalizes everything according to the new endpoint provided.
+    /// It can be called anytime.
+    /// - Throws: ZcashError when failures occur and related to `synchronizer.start(retry: Bool)`, it's the only throwing operation
+    /// during the whole endpoint change.
+    func switchTo(endpoint: LightWalletEndpoint) async throws
 }
 
 public enum SyncStatus: Equatable {

Sources/ZcashLightClientKit/Synchronizer/Dependencies.swift

@@ -18,7 +18,7 @@ enum Dependencies {
         enableBackendTracing: Bool = false
     ) {
         container.register(type: CheckpointSource.self, isSingleton: true) { _ in
-            return CheckpointSourceFactory.fromBundle(for: networkType)
+            CheckpointSourceFactory.fromBundle(for: networkType)
         }
 
         container.register(type: Logger.self, isSingleton: true) { _ in
@@ -36,7 +36,7 @@ enum Dependencies {
         }
 
         container.register(type: ZcashRustBackendWelding.self, isSingleton: true) { _ in
-            return ZcashRustBackend(
+            ZcashRustBackend(
                 dbData: urls.dataDbURL,
                 fsBlockDbRoot: urls.fsBlockDbRoot,
                 spendParamsPath: urls.spendParamsURL,
@@ -47,7 +47,7 @@ enum Dependencies {
         }
 
         container.register(type: LightWalletService.self, isSingleton: true) { _ in
-            return LightWalletGRPCService(endpoint: endpoint)
+            LightWalletGRPCService(endpoint: endpoint)
         }
 
         container.register(type: TransactionRepository.self, isSingleton: true) { _ in

Sources/ZcashLightClientKit/Synchronizer/SDKSynchronizer.swift

@@ -44,7 +44,7 @@ public class SDKSynchronizer: Synchronizer {
     private let syncSessionIDGenerator: SyncSessionIDGenerator
     private let syncSession: SyncSession
     private let syncSessionTicker: SessionTicker
-    let latestBlocksDataProvider: LatestBlocksDataProvider
+    var latestBlocksDataProvider: LatestBlocksDataProvider
 
     /// Creates an SDKSynchronizer instance
     /// - Parameter initializer: a wallet Initializer object
@@ -532,6 +532,90 @@ public class SDKSynchronizer: Synchronizer {
         return subject.eraseToAnyPublisher()
     }
     
+    // MARK: Server switch
+
+    public func switchTo(endpoint: LightWalletEndpoint) async throws {
+        // Stop synchronization
+        let status = await self.status
+        if status != .stopped && status != .disconnected {
+            await blockProcessor.stop()
+        }
+
+        // Validation of the server is first because any custom endpoint can be passed here
+        // Extra instance of the service is created with lower timeout ofr a single call
+        initializer.container.register(type: LightWalletService.self, isSingleton: true) { _ in
+            LightWalletGRPCService(
+                host: endpoint.host,
+                port: endpoint.port,
+                secure: endpoint.secure,
+                singleCallTimeout: 5000,
+                streamingCallTimeout: endpoint.streamingCallTimeoutInMillis
+            )
+        }
+
+        let validateSever = ValidateServerAction(
+            container: initializer.container,
+            configProvider: CompactBlockProcessor.ConfigProvider(config: await blockProcessor.config)
+        )
+ 
+        do {
+            _ = try await validateSever.run(with: ActionContextImpl(state: .idle)) { _ in }
+        } catch {
+            throw ZcashError.synchronizerServerSwitch
+        }
+        
+        // The `ValidateServerAction` confirmed the server is ok and we can continue
+        // final instance of the service will be instantiated and propagated to the all parties
+
+        // SWITCH TO NEW ENDPOINT
+        
+        // LightWalletService dependency update
+        initializer.container.register(type: LightWalletService.self, isSingleton: true) { _ in
+            LightWalletGRPCService(endpoint: endpoint)
+        }
+
+        // DEPENDENCIES
+
+        // BlockDownloaderService dependency update
+        initializer.container.register(type: BlockDownloaderService.self, isSingleton: true) { di in
+            let service = di.resolve(LightWalletService.self)
+            let storage = di.resolve(CompactBlockRepository.self)
+
+            return BlockDownloaderServiceImpl(service: service, storage: storage)
+        }
+
+        // LatestBlocksDataProvider dependency update
+        initializer.container.register(type: LatestBlocksDataProvider.self, isSingleton: true) { di in
+            let service = di.resolve(LightWalletService.self)
+            let rustBackend = di.resolve(ZcashRustBackendWelding.self)
+
+            return LatestBlocksDataProviderImpl(service: service, rustBackend: rustBackend)
+        }
+        
+        // CompactBlockProcessor dependency update
+        Dependencies.setupCompactBlockProcessor(
+            in: initializer.container,
+            config: await blockProcessor.config,
+            accountRepository: initializer.accountRepository
+        )
+        
+        // INITIALIZER
+        initializer.lightWalletService = initializer.container.resolve(LightWalletService.self)
+        initializer.blockDownloaderService = initializer.container.resolve(BlockDownloaderService.self)
+        initializer.endpoint = endpoint
+
+        // SELF
+        self.latestBlocksDataProvider = initializer.container.resolve(LatestBlocksDataProvider.self)
+        
+        // COMPACT BLOCK PROCESSOR
+        await blockProcessor.updateService(initializer.container)
+        
+        // Start synchronization
+        if status != .unprepared {
+            try await start(retry: true)
+        }
+    }
+
     // MARK: notify state
 
     private func snapshotState(status: InternalSyncStatus) async -> SynchronizerState {

Tests/TestUtils/Sourcery/GeneratedMocks/AutoMockable.generated.swift

@@ -1733,6 +1733,25 @@ class SynchronizerMock: Synchronizer {
         }
     }
 
+    // MARK: - switchTo
+
+    var switchToEndpointThrowableError: Error?
+    var switchToEndpointCallsCount = 0
+    var switchToEndpointCalled: Bool {
+        return switchToEndpointCallsCount > 0
+    }
+    var switchToEndpointReceivedEndpoint: LightWalletEndpoint?
+    var switchToEndpointClosure: ((LightWalletEndpoint) async throws -> Void)?
+
+    func switchTo(endpoint: LightWalletEndpoint) async throws {
+        if let error = switchToEndpointThrowableError {
+            throw error
+        }
+        switchToEndpointCallsCount += 1
+        switchToEndpointReceivedEndpoint = endpoint
+        try await switchToEndpointClosure!(endpoint)
+    }
+
 }
 class TransactionRepositoryMock: TransactionRepository {