Confidant

Confidant is a library for storing environmental variables, secrets, feature flags and tokens so all can be easily access throughout your JavaScript/TypeScript project.

Install

yarn add @tdreyno/confidant

Basic Usage

import { SecretsManager } from "aws-sdk"
import {
  Confidant,
  AWSSecret,
  Hardcoded as _,
  LaunchDarkly,
  Inputs,
  Group,
  AWSManager,
} from "@tdreyno/confidant"

const results = await Confidant(
  {
    awsManager: new AWSManager(new SecretsManager({ region: "ap-south-1" })),
  },
  {
    ...DEV,
    url: _("/prod"),
    anotherThing: AWSSecret("MyViasat-TSUsage/PSM/serviceAccount/PROD"),

    launchDarklyKey: AWSSecret("LDKEY FROM AWS"),
    featureA: Inputs("launchDarklyKey").chain(
      LaunchDarkly("feature-a", "default-value"),
    ),

    items: Group({
      first: _(1),
      last: _(1_000_000),
    }),
  },
).initialize()

console.log(results.url)

console.log(results.featureA)

Built-in Tasks

• Hardcoded (often aliased as _): A task which always returns a hard-coded value.
• AWSSecret: A task which loads a string secret from AWS Secret Manager. Must include an instance of awsManager in the Confidant context.
• AWSJSONSecret: A task which loads a JSON secret from AWS Secret Manager. Must include an instance of awsManager in the Confidant context.
• LaunchDarkly: A task which loads a feature flag when provided a launchDarklyUser object in the Confidant context.
• Token is an abstract base class. Create custom Token tasks by inheriting from it and implementing the fetchToken method which returns a Promise<string>
• DecodedJWT is a task which takes a JWT string and a function for converting the decoded object into a typed and validated data structure.
• Inputs is a task which listens to other tasks by key name. When all those tasks are loaded (or updated), pass the values to a dependent task via .chain. Allows composition of tasks.
• Group is a task which groups a set of tasks into a single object.

Add Logger

Provide a winston logger as the 3rd parameter to Confidant. Can be accessed as this.logger in custom Tasks.

Can be used to forward logs to 3rd party logging platforms.

import { createLogger, transports } from "winston"
import { Confidant, Task } from "@tdreyno/confidant"

class MyToken extends Token<MyTokenData> {
  constructor(
    confidant: Confidant<MyTokenData, Record<string, any>>,
    public url_: string,
    public username_: string,
    public password_: string,
  ) {
    super(confidant)
  }

  fetchToken(): Promise<string> {
    this.logger.log("My message")

    return fetch(this.url_, {
      username: this.username_,
      password: this.password_,
    })
  }
}

const results = await Confidant(
  {},
  {
    myToken: c => new MyToken(c, "url", "username", "password"),
  },
  {
    logger: createLogger({
      transports: [new transports.Console()],
    }),
  },
).initialize()

console.log(results.myToken)

Invalidate JWT

import { Confidant } from "@tdreyno/confidant"

const confidant = Confidant(
  {},
  {
    myJWT: MyJWT("url", "username", "password"),
  },
)

const results = await confidant.initialize()

await confidant.invalidate("myJWT")

const newValue = await confidant.get("myJWT")