SWIFT-587 Retryable Reads (#341)

Author: patrickfreed

Sources/MongoSwift/MongoClient.swift

@@ -32,11 +32,10 @@ public struct ClientOptions: CodingStrategyProvider, Decodable {
     /// Specifies a ReadPreference to use for the client.
     public var readPreference: ReadPreference? = nil
 
-    /// Determines whether the client should retry supported read operations.
-    // TODO: SWIFT-587 make this public.
-    internal var retryReads: Bool?
+    /// Determines whether the client should retry supported read operations (on by default).
+    public var retryReads: Bool?
 
-    /// Determines whether the client should retry supported write operations.
+    /// Determines whether the client should retry supported write operations (on by default).
     public var retryWrites: Bool?
 
     /**
@@ -67,7 +66,7 @@ public struct ClientOptions: CodingStrategyProvider, Decodable {
     public var writeConcern: WriteConcern?
 
     private enum CodingKeys: CodingKey {
-        case retryWrites, readConcern, writeConcern
+        case retryWrites, retryReads, readConcern, writeConcern
     }
 
     /// Convenience initializer allowing any/all to be omitted or optional.
@@ -78,6 +77,7 @@ public struct ClientOptions: CodingStrategyProvider, Decodable {
         notificationCenter: NotificationCenter? = nil,
         readConcern: ReadConcern? = nil,
         readPreference: ReadPreference? = nil,
+        retryReads: Bool? = nil,
         retryWrites: Bool? = nil,
         serverMonitoring: Bool = false,
         tlsOptions: TLSOptions? = nil,
@@ -91,6 +91,7 @@ public struct ClientOptions: CodingStrategyProvider, Decodable {
         self.readConcern = readConcern
         self.readPreference = readPreference
         self.retryWrites = retryWrites
+        self.retryReads = retryReads
         self.serverMonitoring = serverMonitoring
         self.tlsOptions = tlsOptions
         self.uuidCodingStrategy = uuidCodingStrategy

Sources/MongoSwift/MongoCollection.swift

@@ -17,7 +17,7 @@ public struct SyncMongoCollection<T: Codable> {
     internal let _client: SyncMongoClient
 
     /// The namespace for this collection.
-    private let namespace: MongoNamespace
+    internal let namespace: MongoNamespace
 
     /// Encoder used by this collection for BSON conversions. (e.g. converting `CollectionType`s, indexes, and options
     /// to documents).

Tests/LinuxMain.swift

@@ -276,6 +276,12 @@ extension ReadWriteConcernTests {
     ]
 }
 
+extension RetryableReadsTests {
+    static var allTests = [
+        ("testRetryableReads", testRetryableReads),
+    ]
+}
+
 extension RetryableWritesTests {
     static var allTests = [
         ("testRetryableWrites", testRetryableWrites),
@@ -310,6 +316,7 @@ XCTMain([
     testCase(OptionsTests.allTests),
     testCase(ReadPreferenceTests.allTests),
     testCase(ReadWriteConcernTests.allTests),
+    testCase(RetryableReadsTests.allTests),
     testCase(RetryableWritesTests.allTests),
     testCase(SDAMTests.allTests),
 ])

Tests/MongoSwiftTests/ChangeStreamTests.swift

@@ -69,7 +69,7 @@ internal struct ChangeStreamTestOperation: Decodable {
     internal func execute(using client: SyncMongoClient) throws -> TestOperationResult? {
         let db = client.db(self.database)
         let coll = db.collection(self.collection)
-        return try self.operation.op.execute(client: client, database: db, collection: coll, session: nil)
+        return try self.operation.execute(on: .collection(coll), session: nil)
     }
 }
 

Tests/MongoSwiftTests/RetryableReadsTests.swift

@@ -0,0 +1,72 @@
+import Foundation
+import MongoSwift
+import Nimble
+import XCTest
+
+/// Struct representing a single test within a spec test JSON file.
+private struct RetryableReadsTest: SpecTest {
+    let description: String
+
+    let operations: [TestOperationDescription]
+
+    let clientOptions: ClientOptions?
+
+    let useMultipleMongoses: Bool?
+
+    let skipReason: String?
+
+    let failPoint: FailPoint?
+
+    let expectations: [TestCommandStartedEvent]?
+}
+
+/// Struct representing a single retryable-writes spec test JSON file.
+private struct RetryableReadsTestFile: Decodable, SpecTestFile {
+    private enum CodingKeys: String, CodingKey {
+        case name, runOn, databaseName = "database_name", collectionName = "collection_name", data, tests
+    }
+
+    let name: String
+
+    let runOn: [TestRequirement]?
+
+    let databaseName: String
+
+    let collectionName: String?
+
+    let data: TestData
+
+    let tests: [RetryableReadsTest]
+}
+
+final class RetryableReadsTests: MongoSwiftTestCase, FailPointConfigured {
+    var activeFailPoint: FailPoint?
+
+    override func tearDown() {
+        self.disableActiveFailPoint()
+    }
+
+    override func setUp() {
+        self.continueAfterFailure = false
+    }
+
+    func testRetryableReads() throws {
+        let skippedTestKeywords = [
+            "findOne", // TODO: SWIFT-643: Unskip this test
+            "changeStream", // TODO: SWIFT-648: Unskip this test
+            "gridfs",
+            "count.",
+            "count-",
+            "mapReduce"
+        ]
+
+        let tests = try retrieveSpecTestFiles(specName: "retryable-reads", asType: RetryableReadsTestFile.self)
+        for (_, testFile) in tests {
+            guard skippedTestKeywords.allSatisfy({ !testFile.name.contains($0) }) else {
+                fileLevelLog("Skipping tests from file \(testFile.name)...")
+                continue
+            }
+            try testFile.runTests(parent: self)
+        }
+    }
+}

Tests/MongoSwiftTests/RetryableWritesTests.swift

@@ -3,10 +3,15 @@ import Foundation
 import Nimble
 import XCTest
 
-/// Struct representing a single test within a spec test JSON file.
-private struct RetryableWritesTest: Decodable, SpecTest {
+/// Struct representing a single test within a retryable-writes spec test JSON file.
+private struct RetryableWritesTest: Decodable {
+    /// Description of the test.
     let description: String
+
+    /// The expected outcome of executing the operation.
     let outcome: TestOutcome
+
+    /// The operation to execute as part of this test case.
     let operation: AnyTestOperation
 
     /// Options used to configure the `SyncMongoClient` used for this test.
@@ -67,12 +72,12 @@ final class RetryableWritesTests: MongoSwiftTestCase, FailPointConfigured {
 
             if let requirements = testFile.runOn {
                 guard requirements.contains(where: { $0.isMet(by: version, MongoSwiftTestCase.topologyType) }) else {
-                    print("Skipping tests from file \(fileName), deployment requirements not met.")
+                    fileLevelLog("Skipping tests from file \(fileName), deployment requirements not met.")
                     continue
                 }
             }
 
-            print("\n------------\nExecuting tests from file \(fileName)...\n")
+            fileLevelLog("Executing tests from file \(fileName)...\n")
             for test in testFile.tests {
                 print("Executing test: \(test.description)")
 
@@ -90,7 +95,35 @@ final class RetryableWritesTests: MongoSwiftTestCase, FailPointConfigured {
                 }
                 defer { self.disableActiveFailPoint() }
 
-                try test.run(client: client, db: db, collection: collection, session: nil)
+                var result: TestOperationResult?
+                var seenError: Error?
+
+                do {
+                    result = try test.operation.execute(on: .collection(collection), session: nil)
+                } catch {
+                    if case let ServerError.bulkWriteError(_, _, _, bulkResult, _) = error {
+                        result = TestOperationResult(from: bulkResult)
+                    }
+                    seenError = error
+                }
+
+                if test.outcome.error ?? false {
+                    expect(seenError).toNot(beNil(), description: test.description)
+                } else {
+                    expect(seenError).to(beNil(), description: test.description)
+                }
+
+                if let expectedResult = test.outcome.result {
+                    expect(result).toNot(beNil())
+                    expect(result).to(equal(expectedResult))
+                }
+
+                let verifyColl = db.collection(test.outcome.collection.name ?? collection.name)
+                let foundDocs = try Array(verifyColl.find())
+                expect(foundDocs.count).to(equal(test.outcome.collection.data.count))
+                zip(foundDocs, test.outcome.collection.data).forEach {
+                    expect($0).to(sortedEqual($1), description: test.description)
+                }
             }
         }
     }

Tests/MongoSwiftTests/SpecTestRunner/Match.swift

@@ -90,6 +90,9 @@ extension BSON: Matchable {
         case let (.array(actual), .array(expected)):
             return actual.matches(expected: expected)
         default:
+            if let selfInt = self.asInt(), let expectedInt = expected.asInt() {
+                return selfInt == expectedInt
+            }
             return self == expected
         }
     }