fix(major): Change KV API to indicate value for not existing key. (#10)

ordo-one · Jul 17, 2024 · f5f2330 · f5f2330
1 parent e912d47
commit f5f2330
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Showing 3 changed files with 25 additions and 8 deletions.
diff --git a/Sources/ConsulServiceDiscovery/Consul.swift b/Sources/ConsulServiceDiscovery/Consul.swift
@@ -305,18 +305,23 @@ public final class Consul: Sendable {
         /// - Parameters
         ///    - key: specifies the path of the key
         ///    - datacenter: Specifies the datacenter to query. This will default to the datacenter of the agent being queried.
-        /// - Returns: EventLoopFuture<Value> to deliver result
+        /// - Returns: EventLoopFuture<Value?> to deliver result, future will sucess with 'nil' if key does not exist
         /// [apidoc]: https://developer.hashicorp.com/consul/api-docs/kv#read-key
         ///
-        public func valueForKey(_ key: String, inDatacenter datacenter: String? = nil) -> EventLoopFuture<Value> {
+        public func valueForKey(_ key: String, inDatacenter datacenter: String? = nil) -> EventLoopFuture<Value?> {
             struct ResponseHandler: ConsulResponseHandler {
-                private let promise: EventLoopPromise<Value>
+                private let promise: EventLoopPromise<Value?>
 
-                init(_ promise: EventLoopPromise<Value>) {
+                init(_ promise: EventLoopPromise<Value?>) {
                     self.promise = promise
                 }
 
                 func processResponse(_ buffer: ByteBuffer, withIndex: Int?) {
+                    if buffer.readableBytes == 0 {
+                        promise.succeed(nil)
+                        return
+                    }
+
                     guard let bytes = buffer.getBytes(at: buffer.readerIndex, length: buffer.readableBytes) else {
                         fatalError("Internal error: bytes unexpectedly nil")
                     }
@@ -369,7 +374,7 @@ public final class Consul: Sendable {
                 components.queryItems = queryItems
             }
 
-            let promise = impl.makePromise(of: Value.self)
+            let promise = impl.makePromise(of: Value?.self)
             if let requestURI = components.string {
                 impl.request(method: .GET, uri: requestURI, body: nil, handler: ResponseHandler(promise))
             } else {

diff --git a/Sources/ConsulServiceDiscovery/Service.swift b/Sources/ConsulServiceDiscovery/Service.swift
@@ -149,7 +149,7 @@ public struct NodeService: Hashable, Decodable, Sendable {
 
 public struct Value: Hashable, Decodable, Sendable {
     public let flags: Int?
-    public let key: String?
+    public let key: String
     public let value: String?
     public let createIndex: Int?
     public let modifyIndex: Int?

diff --git a/Tests/ConsulServiceDiscoveryTests/ConsulTests.swift b/Tests/ConsulServiceDiscoveryTests/ConsulTests.swift
@@ -1,5 +1,6 @@
 @testable import ConsulServiceDiscovery
 import NIOPosix
+import class NIOCore.EventLoopFuture
 import XCTest
 
 final class ConsulTests: XCTestCase {
@@ -94,9 +95,9 @@ final class ConsulTests: XCTestCase {
         XCTAssertTrue(keys2.contains(where: { $0 == testKey }))
 
         let future3 = consul.kv.valueForKey(testKey)
-        let value = try future3.wait()
+        let value = try XCTUnwrap(future3.wait(), "value is unexpectedly empty")
 
-        let valueValue = try XCTUnwrap(value.value, "value is unexpectedly empty")
+        let valueValue = try XCTUnwrap(value.value, "value.value is unexpectedly empty")
         XCTAssertEqual(valueValue, testValue)
 
         let future4 = consul.kv.removeValue(forKey: testKey)
@@ -108,4 +109,15 @@ final class ConsulTests: XCTestCase {
 
         try consul.syncShutdown()
     }
+
+    func testKVDoesNotExist() throws {
+        let consul = Consul()
+
+        let testKey = "test-key-does-not-exist"
+        let future1 = consul.kv.valueForKey(testKey)
+        let value = try future1.wait()
+        XCTAssertEqual(value, nil)
+
+        try consul.syncShutdown()
+    }
 }