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denoland-deno/log/handlers.ts
2019-08-24 10:38:18 -07:00

120 lines
2.7 KiB
TypeScript

// Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
const { open } = Deno;
type File = Deno.File;
type Writer = Deno.Writer;
import { getLevelByName, LogLevel } from "./levels.ts";
import { LogRecord } from "./logger.ts";
import { red, yellow, blue, bold } from "../fmt/colors.ts";
const DEFAULT_FORMATTER = "{levelName} {msg}";
type FormatterFunction = (logRecord: LogRecord) => string;
interface HandlerOptions {
formatter?: string | FormatterFunction;
}
export class BaseHandler {
level: number;
levelName: string;
formatter: string | FormatterFunction;
constructor(levelName: string, 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 LogLevel.INFO:
msg = blue(msg);
break;
case LogLevel.WARNING:
msg = yellow(msg);
break;
case LogLevel.ERROR:
msg = red(msg);
break;
case LogLevel.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;
private _encoder = new TextEncoder();
log(msg: string): void {
this._writer.write(this._encoder.encode(msg + "\n"));
}
}
interface FileHandlerOptions extends HandlerOptions {
filename: string;
}
export class FileHandler extends WriterHandler {
private _file!: File;
private _filename: string;
constructor(levelName: string, options: FileHandlerOptions) {
super(levelName, options);
this._filename = options.filename;
}
async setup(): Promise<void> {
// open file in append mode - write only
this._file = await open(this._filename, "a");
this._writer = this._file;
}
async destroy(): Promise<void> {
await this._file.close();
}
}