Change the default config when creating a JSONLogger

Author: Frizlab

Sources/JSONLogger.swift

@@ -13,25 +13,24 @@ import Logging
 /**
  A logger that logs it’s messages to stdout in the JSON format, one log per line.
 
- The line separator is actually customizable, and can be any sequence of bytes.
+ The end of line separator is actually customizable, and can be any sequence of bytes.
  By default it’s “`\n`”.
 
  The separator customization allows you to choose 
   a prefix for the JSON payload (defaults to `[]`),
-  a suffix too (defaults to `[]` too),
-  and an inter-JSON separator (defaults to `[0x0a]`, which is a UNIX newline).
+  a suffix too (defaults to `[0x0a]`, aka. a single UNIX newline),
+  and an inter-JSON separator (defaults to `[]`, same as the prefix).
  For instance if there are two messages logged, you’ll get the following written to the fd:
  ```
  prefix JSON1 suffix separator prefix JSON2 suffix
  ```
 
- This configuration is interesting mostly to generate `json-seq` stream.
- To do this, set the inter-JSON separator to `[]`, the prefix to `[0x1e]` and the suffix to `[0x0a]`,
-  or use the convenience ``forJSONSeq(on:label:metadataProvider:)``.
+ An interesting configuration is setting the prefix to `[0x1e]` and the suffix to `[0x0a]`, which generates a `json-seq` stream.
+ You can use the ``forJSONSeq(on:label:metadataProvider:)`` convenience to get this configuration directly.
 
- Finally, another interesting configuration is to set the separator to `[0xff]` or `[0xfe]`.
+ Another interesting configuration is to set the inter-JSON separator to `[0xff]` or `[0xfe]` (or both).
  These bytes should not appear in valid UTF-8 strings and should be able to be used to separate JSON payloads.
- (Note I’m not sure why `json-seq` does not do that; there must be a good reason, though.
+ (Note I’m not sure why `json-seq` does not do that but there must be a good reason.
  Probably because the resulting output would not be valid UTF-8 anymore.)
 
  The output file descriptor is also customizable and is `stdout` by default. */
@@ -113,7 +112,7 @@ public struct JSONLogger : LogHandler {
 	public init(
 		label: String,
 		fd: FileDescriptor = .standardOutput,
-		lineSeparator: Data = Data("\n".utf8), prefix: Data = Data(), suffix: Data = Data(),
+		lineSeparator: Data = Data(), prefix: Data = Data(), suffix: Data = Data("\n".utf8),
 		jsonEncoder: JSONEncoder = Self.defaultJSONEncoder,
 		jsonCodersForStringConvertibles: (JSONEncoder, JSONDecoder) = Self.defaultJSONCodersForStringConvertibles,
 		metadataProvider: Logger.MetadataProvider? = LoggingSystem.metadataProvider

Tests/JSONLoggerTests.swift

@@ -49,12 +49,12 @@ final class JSONLoggerTests: XCTestCase {
 		XCTAssertEqual("second", logger2[metadataKey: "only-on"])
 	}
 
-	/* Must be the first test. */
+	/* ⚠️ Must be the first test. */
 	func test0NoSeparatorForFirstLog() throws {
 		/* We do not init the JSONLogger using Logger because we want to test multiple configurations
 		 *  which is not possible using LoggingSystem as the bootstrap can only be done once. */
 		let pipe = Pipe()
-		let jsonLogger = JSONLogger(label: "best-logger", fd: FileDescriptor(rawValue: pipe.fileHandleForWriting.fileDescriptor))
+		let jsonLogger = JSONLogger(label: "best-logger", fd: FileDescriptor(rawValue: pipe.fileHandleForWriting.fileDescriptor), lineSeparator: Data([0x0a]), prefix: Data(), suffix: Data())
 		jsonLogger.log(level: .info, message: "First log message", metadata: nil, source: "dummy-source", file: "dummy-file", function: "dummy-function", line: 42)
 		try pipe.fileHandleForWriting.close()
 		let data = try pipe.fileHandleForReading.readToEnd() ?? Data()
@@ -63,7 +63,7 @@ final class JSONLoggerTests: XCTestCase {
 
 	func testSeparatorForNotFirstLog() throws {
 		let pipe = Pipe()
-		let jsonLogger = JSONLogger(label: "best-logger", fd: FileDescriptor(rawValue: pipe.fileHandleForWriting.fileDescriptor))
+		let jsonLogger = JSONLogger(label: "best-logger", fd: FileDescriptor(rawValue: pipe.fileHandleForWriting.fileDescriptor), lineSeparator: Data([0x0a]), prefix: Data(), suffix: Data())
 		jsonLogger.log(level: .info, message: "Not first log message", metadata: nil, source: "dummy-source", file: "dummy-file", function: "dummy-function", line: 42)
 		try pipe.fileHandleForWriting.close()
 		let data = try pipe.fileHandleForReading.readToEnd() ?? Data()