feat(cdk-dasm): generate cdk code from cloudformation

packages/cdk-dasm/.gitignore

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+*.js
+*.d.ts
+!deps.js
+test/fixture/.jsii
+cdk.schema.json

packages/cdk-dasm/README.md

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+# CDK CloudFormation Disassembler
+
+[![experimental](http://badges.github.io/stability-badges/dist/experimental.svg)](http://github.com/badges/stability-badges)
+
+----
+
+## __WIP__ - this module is still not fully functional:
+
+- [ ] Does not handle intrinsic functions
+- [ ] Only handles the "Resources" section (parameters, outputs, mappings,
+  conditions, ...)
+- [ ] Keys in JSON blobs (such as IAM policies) are converted to camel case
+  (instead of remain as pascal case).
+- [ ] Only TypeScript is supported
+
+-----
+
+Converts an AWS CloudFormation template into AWS CDK code which synthesizes the
+same exact template.
+
+## Why you should not use this tool?
+
+Generally, this is not a recommended approach when using the AWS CDK, but some
+people may find this useful as a means to get started or migrate an existing
+template.
+
+Using this method means that you will have to use the low-level resources (e.g.
+`s3.CfnBucket` instead of `s3.Bucket`). This means that you lose a substantial
+portion of the value of the CDK, which abstracts away much of the boilerplate
+and glue logic required to work with AWS resources.
+
+For example, this is how you would define an S3 bucket encrypted with a KMS key
+with high-level resources:
+
+```ts
+new s3.Bucket(this, 'MyBucket', {
+  encryption: s3.BucketEncryption.Kms
+});
+```
+
+And this is how the same exact configuration will be defined using low-level
+resources:
+
+```ts
+new kms.CfnKey(this, 'MyBucketKeyC17130CF', {
+    keyPolicy: {
+      "statement": [
+        {
+          "action": [ "kms:Create*", "kms:Describe*", "kms:Enable*", "kms:List*", "kms:Put*", "kms:Update*", "kms:Revoke*", "kms:Disable*", "kms:Get*", "kms:Delete*", "kms:ScheduleKeyDeletion", "kms:CancelKeyDeletion" ],
+          "effect": "Allow",
+          "principal": {
+            "aws": { "Fn::Join": [ "", [ "arn:", { "Ref": "AWS::Partition" }, ":iam::", { "Ref": "AWS::AccountId" }, ":root" ] ] }
+          },
+          "resource": "*"
+        }
+      ],
+      "version": "2012-10-17"
+    }
+});
+
+new s3.CfnBucket(this, 'MyBucketF68F3FF0', {
+    bucketEncryption: {
+      "serverSideEncryptionConfiguration": [
+        {
+          "serverSideEncryptionByDefault": {
+            "kmsMasterKeyId": Fn.getAtt('MyBucketKeyC17130CF', 'Arn').toString(),
+            "sseAlgorithm": "aws:kms"
+          }
+        }
+      ]
+    },
+});
+```
+As you can see, there are a lot of details here that you really don't want to
+care about (like the value to put under `sseAlgorithm` or which actions are
+required in the key policy so the key can be managed by administrators. Also,
+this is actually one of the more simple examples we have in the CDK.
+
+The AWS Construct Library includes a very large amount of "undifferentiated
+heavy lifting" that you can only enjoy if you use the high level resources which
+encapsulate all this goodness for you behind a nice clean object-oriented API.
+
+Therefore, we encourage you to use the high-level constructs in the AWS
+Construct Library as much as possible. If you encounter a gap or missing
+capability or resource, take a look at the [Escape
+Hatches](https://docs.aws.amazon.com/CDK/latest/userguide/cfn_layer.html)
+section of the User Guide.
+
+## Usage
+
+```console
+$ cdk-dasm < my-stack-template.json > my-stack.ts
+```
+
+For example, given:
+
+```json
+{
+  "Resources": {
+    "MyTopic": {
+      "Type": "AWS::SNS::Topic",
+      "Properties": {
+        "DisplayName": "YoTopic"
+      }
+    }
+  }
+}
+```
+
+The output will be:
+
+```ts
+
+```

packages/cdk-dasm/bin/cdk-dasm

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+#!/usr/bin/env node
+require('./cdk-dasm.js');

packages/cdk-dasm/bin/cdk-dasm.ts

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+import YAML = require('yaml');
+import { dasmTypeScript } from '../lib';
+
+let s = '';
+process.stdin.resume();
+process.stdin.on('data', data => {
+  s += data.toString('utf-8');
+});
+
+process.stdin.on('end', () => {
+  dasmTypeScript(YAML.parse(s)).then(out => {
+    process.stdout.write(out);
+  });
+});

packages/cdk-dasm/lib/dasm.ts

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+import { CodeMaker, toCamelCase } from 'codemaker';
+import fs = require('fs');
+import os = require('os');
+import path = require('path');
+import { promisify, deprecate } from 'util';
+
+const mkdtemp = promisify(fs.mkdtemp);
+const readFile = promisify(fs.readFile);
+
+interface ConstructDefinition {
+  namespace: string;
+  className: string;
+  id: string;
+  props: { [key: string]: any };
+}
+
+export async function dasmTypeScript(template: Template) {
+  const definitions = new Array<ConstructDefinition>();
+
+  for (const [ id, resource ] of Object.entries(template.Resources || {})) {
+    const type = resource.Type;
+    const props = resource.Properties || {};
+
+    definitions.push({
+      id,
+      ...toCfnClassName(type),
+      props: capitalizeKeys(props)
+    });
+  }
+
+  const code = new CodeMaker();
+
+  const outFile = 'out.ts';
+
+  code.openFile(outFile);
+
+  code.line(`// generated by cdk-dasm at ${new Date().toISOString()}`);
+  code.line();
+
+  //
+  // imports
+  //
+
+  code.line(`import { Stack, StackProps, Construct, Fn } from '@aws-cdk/cdk';`);
+
+  for (const def of definitions) {
+    const importName = `@aws-cdk/aws-${def.namespace}`;
+    code.line(`import ${def.namespace} = require('${importName}');`);
+  }
+
+  code.line();
+
+  //
+  // stack
+  //
+
+  code.openBlock(`export class MyStack extends Stack`);
+  code.openBlock(`constructor(scope: Construct, id: string, props: StackProps = {})`);
+  code.line(`super(scope, id, props);`);
+
+  for (const def of definitions) {
+
+    // no props
+    if (Object.keys(def.props).length === 0) {
+      code.line(`new ${def.className}(this, '${def.id}');`);
+      continue;
+    }
+
+    code.indent(`new ${def.className}(this, '${def.id}', {`);
+
+    for (const [key, value] of Object.entries(def.props)) {
+      const json = JSON.stringify(value, undefined, 2);
+      const [ first, ...rest ] = json.split('\n');
+
+      if (rest.length === 0) {
+        code.line(`${key}: ${first},`); // single line
+      } else {
+        code.line(`${key}: ${first}`);
+        rest.forEach((r, i) => {
+          code.line(r + ((i === rest.length - 1) ? ',' : ''));
+        });
+      }
+    }
+
+    code.unindent('});');
+  }
+
+  code.closeBlock();
+
+  code.closeBlock(' // MyStack');
+
+  code.closeFile(outFile);
+
+  const workdir = await mkdtemp(path.join(os.tmpdir(), 'cdk-dasm-typescript'));
+  await code.save(workdir);
+
+  return (await readFile(path.join(workdir, outFile))).toString();
+}
+
+function capitalizeKeys(x: any): any {
+  if (typeof(x) === 'function') {
+    throw new Error(`function?`);
+  }
+
+  if (Array.isArray(x)) {
+    return x.map(i => capitalizeKeys(i));
+  }
+
+  if (typeof(x) === 'object') {
+    const ret: { [key: string]: any } = {};
+    for (const [ key, value ] of Object.entries(x)) {
+      let newKey;
+      if (key === 'Ref' || key.startsWith('Fn::')) {
+        newKey = key;
+      } else {
+        newKey = toCamelCase(key);
+      }
+
+      ret[newKey] = capitalizeKeys(value);
+    }
+    return ret;
+  }
+
+  // primitive
+  return x;
+}
+
+function toCfnClassName(resourceType: string) {
+  const [ , namespace, type ] = resourceType.split('::');
+  const className = `${namespace.toLocaleLowerCase()}.Cfn${type}`;
+  return { namespace: namespace.toLocaleLowerCase(), className };
+}
+
+interface Template {
+  Resources: { [id: string]: Resource };
+}
+
+interface Resource {
+  Type: string;
+  Properties?: { [prop: string]: any }
+}

packages/cdk-dasm/lib/index.ts

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+export * from './dasm';