universe-log

Universal javascript log for node and browser. Suitable for libraries and microservices. Configurable via env and window. Extendable

Main aim of universe log is the easiness of configuration via ENV variables. Universe log main goals:

• Configuration via portable env variables: window.LOG_FORMAT works as well as process.env.LOG_FORMAT

• Pluggable configuration via scoped env variables: choose WISE_LOG_LEVEL to set log level across all wise libraries, or use WISE_HUB_CORE_LEVEL to tune log level of wise-core library solely. Importance stack is specified in abstract class sonstructor

• log format is configurable via LOG_FORMAT field. When you set it to json it will produce logs with extra metadata: error stacks, custom errors (with cause), timestamps, and project specific metadata.

Install

$ npm install --save universe-log

Use in your project (typescript)

Best practice to use universe-log is to create a singleton Log class in your project that extends AbstractUniverseLog.

import { AbstractUniverseLog, PortableEnv } from "universe-log";

export class Log extends AbstractUniverseLog {
    public static log(): Log {
        if (!Log.INSTANCE) {
            Log.INSTANCE = new Log();
        }

        return Log.INSTANCE;
    }

    private static INSTANCE: Log;

    public constructor() {
        super({
            metadata: {
                project: "wise-hub",
                environment: PortableEnv("WISE_ENVIRONMENT_TYPE"),
                service: "monitoring",
                /** This metadata could be merged (and overriden) by LOG_METADATA env. Here is an example:
                 * LOG_METADATA={ "module": "publisher" }
                 * With this env, json log will produce output that contains merged instance metadata and the metadata from env LOG_METADATA.
                 */
            },
            levelEnvs: ["WISE_LOG_LEVEL", "WISE_SUBPROJECT_LOG_LEVEL"],
        });
    }
}

Across your project:

Log.log().info("Info");
Log.log().infoGen(() => "costly log generation");

Configuration

Format:

• Configurable via LOG_FORMAT env. Available formats are: json, json_pretty, oneline. The default is oneline.

Level:

• Configurable via envs specified in level_envs field of super() call. Universe-log chooses the most verbose level supplied. When no configurable envs are present, universe-log looks for LOG_LEVEL env. If it is also not present, a default info level is used.

Metadata:

• metadata field in super() call is merged with the value of LOG_METADATA env (if a field exists in both, it is overriden by LOG_METADATA env). LOG_METADATA should contain stringified JSON.