ListTables done

Author: meyertst-aws

swift/example_code/dynamodb/ListTables/Sources/DatabaseManager.swift

@@ -6,9 +6,9 @@
 /// SPDX-License-Identifier: Apache-2.0
 
 // snippet-start:[ddb.swift.databasemanager-all]
-import Foundation
 import AWSDynamoDB
 import ClientRuntime
+import Foundation
 
 /// A protocol describing the implementation of functions that allow either
 /// calling through to Amazon DynamoDB or mocking DynamoDB functions.
@@ -22,26 +22,32 @@ public protocol DatabaseSession {
     /// - Parameter input: A `ListTablesInput` object specifying the input
     ///   parameters for the call to `listTables()`.
     ///
-    /// - Returns: A `ListTablesOutput` structure with the results.
-    func listTables(input: ListTablesInput) async throws -> ListTablesOutput
+    /// - Returns: A `[String]` list of table names..
+    func listTables(input: ListTablesInput) async throws -> [String]
 }
 
 // snippet-start:[ddb.swift.dynamodbsession]
 /// An implementation of the `DatabaseSession` protocol that calls through to
 /// DynamoDB for its operations.
 public struct DynamoDBSession: DatabaseSession {
-    let awsRegion: String
     let client: DynamoDBClient
 
     // snippet-start:[ddb.swift.dynamodbsession.init]
     /// Initialize the `DatabaseSession`.
     ///
     /// - Parameter region: The AWS Region to use for DynamoDB.
     ///
-    init(region: String = "us-east-2") throws {
-        self.awsRegion = region
-        self.client = try DynamoDBClient(region: awsRegion)
+    init(region: String? = nil) async throws {
+        do {
+            let config = try await DynamoDBClient.DynamoDBClientConfiguration()
+            if let region = region {
+                config.region = region
+            }
+
+            self.client = DynamoDBClient(config: config)
+        }
     }
+
     // snippet-end:[ddb.swift.dynamodbsession.init]
 
     // snippet-start:[ddb.swift.dynamodbsession.listtables]
@@ -52,13 +58,31 @@ public struct DynamoDBSession: DatabaseSession {
     ///   `ListTablesInput` object.
     ///
     /// - Returns: The `ListTablesOutput` returned by `listTables()`.
-    /// 
+    ///
     /// - Throws: Errors from DynamoDB are thrown as usual.
-    public func listTables(input: ListTablesInput) async throws -> ListTablesOutput {
-        return try await client.listTables(input: input)
+    public func listTables(input: ListTablesInput) async throws -> [String] {
+        do {
+            // Use "Paginated" to get all the tables.
+            // This lets the SDK handle the 'lastEvaluatedTableName' property in "ListTablesOutput".
+            let pages = client.listTablesPaginated(input: input)
+
+            var allTableNames: [String] = []
+            for try await page in pages {
+                guard let tableNames = page.tableNames else {
+                    print("Error: no table names returned.")
+                    continue
+                }
+                allTableNames += tableNames
+            }
+            return allTableNames
+        } catch {
+            print("ERROR: listTables:", dump(error))
+            throw error
+        }
     }
     // snippet-end:[ddb.swift.dynamodbsession.listtables]
 }
+
 // snippet-end:[ddb.swift.dynamodbsession]
 
 // snippet-start:[ddb.swift.databasemanager]
@@ -77,6 +101,7 @@ public class DatabaseManager {
     init(session: DatabaseSession) {
         self.session = session
     }
+
     // snippet-end:[ddb.swift.databasemanager.init]
 
     // snippet-start:[ddb.swift.databasemanager.gettablelist]
@@ -85,29 +110,12 @@ public class DatabaseManager {
     /// - Returns: An array of strings listing all of the tables available
     ///   in the Region specified when the session was created.
     public func getTableList() async throws -> [String] {
-        var tableList: [String] = []
-        var lastEvaluated: String? = nil
-
-        // Iterate over the list of tables, 25 at a time, until we have the
-        // names of every table. Add each group to the `tableList` array.
-        // Iteration is complete when `output.lastEvaluatedTableName` is `nil`.
-
-        repeat {
-            let input = ListTablesInput(
-                exclusiveStartTableName: lastEvaluated,
-                limit: 25
-            )
-            let output = try await self.session.listTables(input: input)
-            guard let tableNames = output.tableNames else {
-                return tableList
-            }
-            tableList.append(contentsOf: tableNames)
-            lastEvaluated = output.lastEvaluatedTableName
-        } while lastEvaluated != nil
-
-        return tableList
+        let input = ListTablesInput(
+        )
+        return try await session.listTables(input: input)
     }
     // snippet-end:[ddb.swift.databasemanager.gettablelist]
 }
+
 // snippet-end:[ddb.swift.databasemanager]
 // snippet-end:[ddb.swift.databasemanager-all]

swift/example_code/dynamodb/ListTables/Sources/listtables.swift

@@ -7,14 +7,14 @@
 /// SPDX-License-Identifier: Apache-2.0
 
 // snippet-start:[ddb.swift.listtables]
-import Foundation
 import ArgumentParser
 import AWSDynamoDB
 import ClientRuntime
+import Foundation
 
 struct ExampleCommand: ParsableCommand {
     @Option(help: "The AWS Region to run AWS API calls in.")
-    var awsRegion = "us-east-2"
+    var awsRegion: String?
 
     @Option(
         help: ArgumentHelp("The level of logging for the Swift SDK to perform."),
@@ -45,7 +45,7 @@ struct ExampleCommand: ParsableCommand {
 
     /// Called by ``main()`` to asynchronously run the AWS example.
     func runAsync() async throws {
-        let session = try DynamoDBSession(region: awsRegion)
+        let session = try await DynamoDBSession(region: awsRegion)
         let dbManager = DatabaseManager(session: session)
 
         let tableList = try await dbManager.getTableList()
@@ -72,4 +72,5 @@ struct Main {
         }
     }
 }
+
 // snippet-end:[ddb.swift.listtables]

swift/example_code/dynamodb/ListTables/Tests/ListTablesTests.swift

@@ -80,54 +80,19 @@ public struct MockDBSession: DatabaseSession {
     /// Mock version of the DynamoDB client's `listTables()` function. Returns
     /// values from the string array `fakeTableNames` or the one specified as
     /// an optional input when creating the `MockDBSession`.
-    public func listTables(input: ListTablesInput) async throws -> ListTablesOutput {
-        var output = ListTablesOutput(
-            lastEvaluatedTableName: nil,
-            tableNames: nil
-        )
-
-        // Stop at once if there are no table names in the list.
-        
-        if testTableNames.count == 0 {
-            return output
+    public func listTables(input: ListTablesInput) async throws -> [String] {
+         var maxTables = testTableNames.count
+        if let limit = input.limit {
+            maxTables = Swift.min(limit, maxTables)
         }
 
-        var startIndex: Int
-
-        // Get the starting point in the list using the input's
-        // `exclusiveStartTableName` property. If it's `nil` or the string
-        // isn't found in the list, use 0 for the index.
-
-        if input.exclusiveStartTableName != nil {
-            startIndex = testTableNames.firstIndex(of: input.exclusiveStartTableName!) ?? 0
-        } else {
-            startIndex = 0
-        }
-
-        // Split the full list of table names into the number of parts
-        // specified by the `limit` parameter, or 100 parts if `limit` is not
-        // specified.
-
-        let chunkSize = input.limit ?? 100
-        let chunks: [[String]] = stride(from: startIndex, to: testTableNames.count, by: chunkSize).map {
-            Array(testTableNames[$0 ..< Swift.min($0 + chunkSize, testTableNames.count)])
-        }
-
-        output.tableNames = chunks[0]
-        if chunks.count == 1 {
-            output.lastEvaluatedTableName = nil
-        } else {
-            output.lastEvaluatedTableName = chunks[1].first
-        }
-
-        return output
+        return Array(testTableNames[0..<maxTables])
     }
 }
 
 /// Perform tests on the `getTableList()` function.
 final class ListTablesTests: XCTestCase {
-    static let region = "us-east-2"
-
+ 
     /// Class-wide setup function for the test case, which is run *once*
     /// before any tests are run.
     ///
@@ -165,4 +130,4 @@ final class ListTablesTests: XCTestCase {
         let list = try await dbManager.getTableList()
         XCTAssertEqual(list, testNames, "Returned list of table names doesn't match original list.")
     }
-}
+}