feat: config file support

README.md

@@ -13,6 +13,8 @@ The goal for this project is to be _Good Enough_ for local development use, and
 - [x] Initiate Auth (Login)
 - [x] Forgot Password
 - [x] Confirm Forgot Password
+- [x] User Migration lambda trigger (Authentication)
+- [ ] User Migration lambda trigger (Forgot Password)
 
 ## Installation
 
@@ -42,6 +44,61 @@ new CognitoUserPool({
 
 You likely only want to do this when you're running locally on your development machine.
 
+## Configuration
+
+You do not need to supply a config unless you need to customise the behaviour of Congito Local. If you are using Lambda triggers, you will definitely need to override `LambdaClient.endpoint` at a minimum.
+
+Before starting Cognito Local, create a config file:
+
+    mkdir .cognito && echo '{}' > .cognito/config.json
+
+You can edit that `.cognito/config.json` and add any of the following settings:
+
+| Setting                                    | Type       | Default     | Description                                                 |
+| ------------------------------------------ | ---------- | ----------- | ----------------------------------------------------------- |
+| `LambdaClient`                             | `object`   |             | Any setting you would pass to the AWS.Lambda Node.js client |
+| `LambdaClient.credentials.accessKeyId`     | `string`   | `local`     |                                                             |
+| `LambdaClient.credentials.secretAccessKey` | `string`   | `local`     |                                                             |
+| `LambdaClient.endpoint`                    | `string`   | `local`     |                                                             |
+| `LambdaClient.region`                      | `string`   | `local`     |                                                             |
+| `TriggerFunctions`                         | `object`   | `{}`        | Trigger name to Function name mapping                       |
+| `TriggerFunctions.UserMigration`           | `string`   |             | User Migration lambda name                                  |
+| `UserPoolDefaults`                         | `object`   |             | Default behaviour to use for the User Pool                  |
+| `UserPoolDefaults.UserPoolId`              | `string`   | `local`     | Default User Pool Id                                        |
+| `UserPoolDefaults.UsernameAttributes`      | `string[]` | `["email"]` | Username alias attributes                                   |
+
+The default config is:
+
+```json
+{
+  "LambdaClient": {
+    "credentials": {
+      "accessKeyId": "local",
+      "secretAccessKey": "local"
+    },
+    "region": "local"
+  },
+  "TriggerFunctions": {},
+  "UserPoolDefaults": {
+    "UserPoolId": "local",
+    "UsernameAttributes": ["email"]
+  }
+}
+```
+
+## Known Limitations
+
+Many. Cognito Local only works for my exact use-case.
+
+Issues I know about:
+
+- The database is shared for all User Pools, if you use different User Pool IDs they will all access the same database.
+- Client IDs are ignored and all connect to the same User Pool.
+- Users can't be disabled
+- Only `USER_PASSWORD_AUTH` flow is supported
+- You can't reset your password
+- Not all Lambda triggers (yet, watch this space)
+
 ## Confirmation codes
 
 If you register a new user and they need to confirm their account, Cognito Local will write a message to the console with their confirmation code instead of emailing it to the user.
@@ -59,16 +116,3 @@ For example:
 │                                                       │
 ╰───────────────────────────────────────────────────────╯
 ```
-
-## Known Limitations
-
-Many. Cognito Local only works for my exact use-case.
-
-Issues I know about:
-
-- The database is shared for all User Pools, if you use different User Pool IDs they will all access the same database.
-- Client IDs are ignored and all connect to the same User Pool.
-- Users can't be disabled
-- Only `USER_PASSWORD_AUTH` flow is supported
-- You can't reset your password
-- No Lambda triggers (yet, watch this space)

integration-tests/dataStore.test.ts

@@ -94,6 +94,20 @@ describe("Data Store", () => {
   });
 
   describe("get", () => {
+    it("returns entire db if no key used", async () => {
+      const dataStore = await createDataStore(
+        "example",
+        { DefaultValue: true },
+        path
+      );
+
+      await dataStore.set("key", "value");
+
+      const result = await dataStore.get();
+
+      expect(result).toEqual({ DefaultValue: true, key: "value" });
+    });
+
     it("returns a default", async () => {
       const dataStore = await createDataStore(
         "example",

package.json

@@ -56,6 +56,7 @@
     "body-parser": "^1.19.0",
     "boxen": "^4.2.0",
     "cors": "^2.8.5",
+    "deepmerge": "^4.2.2",
     "express": "^4.17.1",
     "jsonwebtoken": "^8.5.1",
     "stormdb": "^0.3.0",

src/server/config.ts

@@ -0,0 +1,33 @@
+import deepmerge from "deepmerge";
+import { createDataStore } from "../services/dataStore";
+import { FunctionConfig } from "../services/lambda";
+import { UserPoolOptions } from "../services/userPool";
+
+export interface Config {
+  LambdaClient: AWS.Lambda.ClientConfiguration;
+  TriggerFunctions: FunctionConfig;
+  UserPoolDefaults: UserPoolOptions;
+}
+
+const defaults: Config = {
+  LambdaClient: {
+    credentials: {
+      accessKeyId: "local",
+      secretAccessKey: "local",
+    },
+    region: "local",
+  },
+  TriggerFunctions: {},
+  UserPoolDefaults: {
+    UserPoolId: "local",
+    UsernameAttributes: ["email"],
+  },
+};
+
+export const loadConfig = async (): Promise<Config> => {
+  const dataStore = await createDataStore("config", defaults, ".cognito");
+
+  const config = await dataStore.get<Config>();
+
+  return deepmerge(defaults, config ?? {});
+};

src/server/defaults.ts

@@ -6,19 +6,21 @@ import { createLambda } from "../services/lambda";
 import { createTriggers } from "../services/triggers";
 import { createUserPool } from "../services/userPool";
 import { Router } from "../targets/router";
+import { loadConfig } from "./config";
 import { createServer, Server } from "./server";
 import * as AWS from "aws-sdk";
 
 export const createDefaultServer = async (): Promise<Server> => {
+  const config = await loadConfig();
+
+  console.log("Loaded config:", config);
+
   const userPool = await createUserPool(
-    {
-      UserPoolId: "local",
-      UsernameAttributes: ["email"],
-    },
+    config.UserPoolDefaults,
     createDataStore
   );
-  const lambdaClient = new AWS.Lambda({});
-  const lambda = createLambda({}, lambdaClient);
+  const lambdaClient = new AWS.Lambda(config.LambdaClient);
+  const lambda = createLambda(config.TriggerFunctions, lambdaClient);
   const triggers = createTriggers({
     lambda,
     userPool,

src/services/dataStore.ts

@@ -5,7 +5,7 @@ import { promisify } from "util";
 const mkdir = promisify(fs.mkdir);
 
 export interface DataStore {
-  get<T>(key: string): Promise<T | null>;
+  get<T>(key?: string): Promise<T | null>;
   set<T>(key: string, value: T): Promise<void>;
 }
 
@@ -30,7 +30,11 @@ export const createDataStore: CreateDataStore = async (
   db.default(defaults);
 
   return {
-    async get(key: string) {
+    async get(key?: string) {
+      if (!key) {
+        return db.value();
+      }
+
       const result = await db.get(key).value();
 
       return result ?? null;

src/services/lambda.ts

@@ -1,5 +1,6 @@
 import { CognitoUserPoolEvent } from "aws-lambda";
 import * as AWS from "aws-sdk";
+import { InvocationResponse } from "aws-sdk/clients/lambda";
 import { UnexpectedLambdaExceptionError } from "../errors";
 
 interface UserMigrationEvent {
@@ -57,13 +58,19 @@ export const createLambda: CreateLambda = (config, lambdaClient) => ({
       `Invoking "${lambdaName}" with event`,
       JSON.stringify(lambdaEvent, undefined, 2)
     );
-    const result = await lambdaClient
-      .invoke({
-        FunctionName: lambdaName,
-        InvocationType: "RequestResponse",
-        Payload: JSON.stringify(lambdaEvent),
-      })
-      .promise();
+    let result: InvocationResponse;
+    try {
+      result = await lambdaClient
+        .invoke({
+          FunctionName: lambdaName,
+          InvocationType: "RequestResponse",
+          Payload: JSON.stringify(lambdaEvent),
+        })
+        .promise();
+    } catch (ex) {
+      console.log(ex);
+      throw new UnexpectedLambdaExceptionError();
+    }
 
     console.log(
       `Lambda completed with StatusCode=${result.StatusCode} and FunctionError=${result.FunctionError}`

src/services/userPool.ts

@@ -24,16 +24,16 @@ export interface UserPool {
 
 type UsernameAttribute = "email" | "phone_number";
 
-interface UserPoolOptions {
-  UserPoolId: string;
-  UsernameAttributes: UsernameAttribute[];
+export interface UserPoolOptions {
+  UserPoolId?: string;
+  UsernameAttributes?: UsernameAttribute[];
 }
 
 export const createUserPool = async (
   options: UserPoolOptions,
   createDataStore: CreateDataStore
 ): Promise<UserPool> => {
-  const dataStore = await createDataStore(options.UserPoolId, {
+  const dataStore = await createDataStore(options.UserPoolId ?? "local", {
     Users: {},
     Options: options,
   });
@@ -61,8 +61,8 @@ export const createUserPool = async (
       console.log("getUserByUsername", username);
 
       const options = await dataStore.get<UserPoolOptions>("Options");
-      const aliasEmailEnabled = options?.UsernameAttributes.includes("email");
-      const aliasPhoneNumberEnabled = options?.UsernameAttributes.includes(
+      const aliasEmailEnabled = options?.UsernameAttributes?.includes("email");
+      const aliasPhoneNumberEnabled = options?.UsernameAttributes?.includes(
         "phone_number"
       );