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// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
const { open, openSync, close, renameSync, statSync } = Deno;
type File = Deno.File;
type Writer = Deno.Writer;
type OpenOptions = Deno.OpenOptions;
import { getLevelByName, LevelName, LogLevels } from "./levels.ts";
import { LogRecord } from "./logger.ts";
import { red, yellow, blue, bold } from "../fmt/colors.ts";
import { existsSync, exists } from "../fs/exists.ts";
const DEFAULT_FORMATTER = "{levelName} {msg}";
type FormatterFunction = (logRecord: LogRecord) => string;
type LogMode = "a" | "w" | "x";
interface HandlerOptions {
formatter?: string | FormatterFunction;
}
export class BaseHandler {
level: number;
levelName: LevelName;
formatter: string | FormatterFunction;
constructor(levelName: LevelName, options: HandlerOptions = {}) {
this.level = getLevelByName(levelName);
this.levelName = levelName;
this.formatter = options.formatter || DEFAULT_FORMATTER;
}
handle(logRecord: LogRecord): void {
if (this.level > logRecord.level) return;
const msg = this.format(logRecord);
return this.log(msg);
}
format(logRecord: LogRecord): string {
if (this.formatter instanceof Function) {
return this.formatter(logRecord);
}
return this.formatter.replace(/{(\S+)}/g, (match, p1): string => {
const value = logRecord[p1 as keyof LogRecord];
// do not interpolate missing values
if (!value) {
return match;
}
return String(value);
});
}
log(_msg: string): void {}
async setup(): Promise<void> {}
async destroy(): Promise<void> {}
}
export class ConsoleHandler extends BaseHandler {
format(logRecord: LogRecord): string {
let msg = super.format(logRecord);
switch (logRecord.level) {
case LogLevels.INFO:
msg = blue(msg);
break;
case LogLevels.WARNING:
msg = yellow(msg);
break;
case LogLevels.ERROR:
msg = red(msg);
break;
case LogLevels.CRITICAL:
msg = bold(red(msg));
break;
default:
break;
}
return msg;
}
log(msg: string): void {
console.log(msg);
}
}
export abstract class WriterHandler extends BaseHandler {
protected _writer!: Writer;
#encoder = new TextEncoder();
abstract log(msg: string): void;
}
interface FileHandlerOptions extends HandlerOptions {
filename: string;
mode?: LogMode;
}
export class FileHandler extends WriterHandler {
protected _file!: File;
protected _filename: string;
protected _mode: LogMode;
protected _openOptions: OpenOptions;
#encoder = new TextEncoder();
constructor(levelName: LevelName, options: FileHandlerOptions) {
super(levelName, options);
this._filename = options.filename;
// default to append mode, write only
this._mode = options.mode ? options.mode : "a";
this._openOptions = {
createNew: this._mode === "x",
create: this._mode !== "x",
append: this._mode === "a",
truncate: this._mode !== "a",
write: true,
};
}
async setup(): Promise<void> {
this._file = await open(this._filename, this._openOptions);
this._writer = this._file;
}
log(msg: string): void {
Deno.writeSync(this._file.rid, this.#encoder.encode(msg + "\n"));
}
destroy(): Promise<void> {
this._file.close();
return Promise.resolve();
}
}
interface RotatingFileHandlerOptions extends FileHandlerOptions {
maxBytes: number;
maxBackupCount: number;
}
export class RotatingFileHandler extends FileHandler {
#maxBytes: number;
#maxBackupCount: number;
constructor(levelName: LevelName, options: RotatingFileHandlerOptions) {
super(levelName, options);
this.#maxBytes = options.maxBytes;
this.#maxBackupCount = options.maxBackupCount;
}
async setup(): Promise<void> {
if (this.#maxBytes < 1) {
throw new Error("maxBytes cannot be less than 1");
}
if (this.#maxBackupCount < 1) {
throw new Error("maxBackupCount cannot be less than 1");
}
await super.setup();
if (this._mode === "w") {
// Remove old backups too as it doesn't make sense to start with a clean
// log file, but old backups
for (let i = 1; i <= this.#maxBackupCount; i++) {
if (await exists(this._filename + "." + i)) {
await Deno.remove(this._filename + "." + i);
}
}
} else if (this._mode === "x") {
// Throw if any backups also exist
for (let i = 1; i <= this.#maxBackupCount; i++) {
if (await exists(this._filename + "." + i)) {
Deno.close(this._file.rid);
throw new Deno.errors.AlreadyExists(
"Backup log file " + this._filename + "." + i + " already exists"
);
}
}
}
}
handle(logRecord: LogRecord): void {
if (this.level > logRecord.level) return;
const msg = this.format(logRecord);
const currentFileSize = statSync(this._filename).size;
if (currentFileSize + msg.length > this.#maxBytes) {
this.rotateLogFiles();
}
return this.log(msg);
}
rotateLogFiles(): void {
close(this._file.rid);
for (let i = this.#maxBackupCount - 1; i >= 0; i--) {
const source = this._filename + (i === 0 ? "" : "." + i);
const dest = this._filename + "." + (i + 1);
if (existsSync(source)) {
renameSync(source, dest);
}
}
this._file = openSync(this._filename, this._openOptions);
this._writer = this._file;
}
}
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