Merge pull request #1 from phuonghuynh/dev

Separate Lambda@Edge module

Author: ronaldtse

.gitignore

@@ -0,0 +1,3 @@
+.archive*
+.idea/
+.iml

main.tf

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+resource "template_dir" "this" {
+  source_dir      = "${path.module}/src"
+  destination_dir = "${path.module}/.archive"
+
+  vars {
+    BUCKET_NAME = "${var.bucket_name}"
+    BUCKET_KEY  = "${var.bucket_key}"
+
+    BASIC_USER = "${var.basic_user}"
+    BASIC_PWD  = "${var.basic_password}"
+  }
+}
+
+data "archive_file" "this" {
+  depends_on = [
+    "template_dir.this",
+  ]
+
+  type        = "zip"
+  output_path = "${path.module}/.archive.zip"
+  source_dir  = "${template_dir.this.destination_dir}"
+}
+
+resource "aws_lambda_function" "this" {
+  description = "Basic HTTP authentication module/function"
+  role        = "${aws_iam_role.this.arn}"
+  runtime     = "nodejs8.10"
+
+  filename         = "${data.archive_file.this.output_path}"
+  source_code_hash = "${data.archive_file.this.output_base64sha256}"
+
+  function_name = "${var.name}"
+  handler       = "basic_auth.handler"
+
+  timeout     = "${var.fn_timeout}"
+  memory_size = "${var.fn_memory_size}"
+  publish     = true
+}

outputs.tf

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+output "fn_name" {
+  value = "${aws_lambda_function.this.function_name}"
+}
+
+output "arn" {
+  value = "${aws_lambda_function.this.arn}"
+}
+
+output "qualified_arn" {
+  value = "${aws_lambda_function.this.qualified_arn}"
+}
+
+output "invoke_arn" {
+  value = "${aws_lambda_function.this.invoke_arn}"
+}
+
+output "id" {
+  value = "${aws_lambda_function.this.id}"
+}
+
+output "version" {
+  value = "${aws_lambda_function.this.version}"
+}

src/basic_auth.js

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+
+const AWS = require('aws-sdk');
+const s3 = new AWS.S3();
+
+//https://medium.com/@yagonobre/automatically-invalidate-cloudfront-cache-for-site-hosted-on-s3-3c7818099868
+exports.handler = async (event, context, callback) => {
+    const request = event.Records[0].cf.request;
+    const uri = request.uri;
+
+    if (!'${BUCKET_NAME}') {
+        console.log(`Bucket not defined (key is empty) => ignore`);
+        return callback(null, request);
+    }
+
+    try {
+        const filesStr = await readRestrictedFiles();
+        if (!filesStr) {
+            throw new Error(`empty protect files => ignore`);
+        }
+
+        const rawFiles = JSON.parse(await readRestrictedFiles());
+        if (!Array.isArray(rawFiles)) {
+            throw new Error('${BUCKET_KEY} is not any array => ignore')
+        }
+        const files = rawFiles.map(f => f.startsWith('/') ? f : '/' + f);
+        if (!files.includes(uri)) {
+            throw new Error(uri + ` not protected`);
+        }
+
+        const headers = request.headers;
+
+        const authUser = '${BASIC_USER}';
+        const authPass = '${BASIC_PWD}';
+
+        const authString = 'Basic ' + new Buffer(authUser + ':' + authPass).toString('base64');
+        if (typeof headers.authorization === 'undefined' || headers.authorization[0].value !== authString) {
+            const body = 'Unauthorized';
+            const response = {
+                status: '401',
+                statusDescription: 'Unauthorized',
+                body: body,
+                headers: {
+                    'www-authenticate': [{key: 'WWW-Authenticate', value:'Basic'}]
+                },
+            };
+            return callback(null, response);
+        }
+    }
+    catch(e) {
+        console.error(e);
+    }
+    return callback(null, request);
+};
+
+async function readRestrictedFiles() {
+    const params = { Bucket: '${BUCKET_NAME}', Key: '${BUCKET_KEY}' };
+    const data =  await s3.getObject(params).promise();
+    return data.Body.toString();
+}

sts_role.tf

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+data "aws_iam_policy_document" "sts" {
+  statement {
+    effect = "Allow"
+
+    actions = [
+      "sts:AssumeRole",
+    ]
+
+    principals {
+      type = "Service"
+
+      identifiers = [
+        "lambda.amazonaws.com",
+        "edgelambda.amazonaws.com",
+      ]
+    }
+  }
+}
+
+data "aws_iam_policy_document" "this" {
+  statement {
+    effect = "Allow"
+
+    actions = [
+      "s3:GetBucketLocation",
+      "s3:ListBucket",
+      "s3:GetObject",
+      "logs:CreateLogGroup",
+      "logs:CreateLogStream",
+      "logs:DescribeLogGroups",
+      "logs:DescribeLogStreams",
+      "logs:PutLogEvents",
+      "logs:GetLogEvents",
+      "logs:FilterLogEvents",
+    ]
+
+    resources = [
+      "arn:aws:logs:*:*:*"
+    ]
+  }
+
+  statement {
+    effect = "Allow"
+
+    actions = [
+      "lambda:GetFunction",
+    ]
+
+    resources = [
+      "${aws_lambda_function.this.arn}:*",
+    ]
+  }
+}
+
+resource "aws_iam_role_policy" "this" {
+  name   = "${var.name}"
+  role   = "${aws_iam_role.this.id}"
+  policy = "${data.aws_iam_policy_document.this.json}"
+}
+
+resource "aws_iam_role" "this" {
+  name               = "${var.name}"
+  assume_role_policy = "${data.aws_iam_policy_document.sts.json}"
+}

vars.tf

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+variable "name" {
+  default = "terraform-aws-lambda-edge-authentication"
+}
+
+// Lambda limits https://docs.aws.amazon.com/AmazonCloudFront/latest/DeveloperGuide/cloudfront-limits.html
+variable "fn_timeout" {
+  default = 3
+}
+
+variable "fn_memory_size" {
+  default = 128
+}
+
+variable "bucket_name" {
+}
+
+variable "bucket_key" {
+}
+
+variable "basic_user" {
+}
+
+variable "basic_password" {
+}