manifest.ts

import * as fs from 'fs';
import * as jsonschema from 'jsonschema';
import * as semver from 'semver';
import * as assets from './assets';
import * as assembly from './cloud-assembly';

/* eslint-disable @typescript-eslint/no-var-requires */
/* eslint-disable @typescript-eslint/no-require-imports */

// this prefix is used by the CLI to identify this specific error.
// in which case we want to instruct the user to upgrade his CLI.
// see exec.ts#createAssembly
export const VERSION_MISMATCH: string = 'Cloud assembly schema version mismatch';

const ASSETS_SCHEMA = require('../schema/assets.schema.json');

const ASSEMBLY_SCHEMA = require('../schema/cloud-assembly.schema.json');

/**
 * Version is shared for both manifests
 */
const SCHEMA_VERSION = require('../schema/cloud-assembly.version.json').version;

/**
 * Protocol utility class.
 */
export class Manifest {
  /**
   * Validates and saves the cloud assembly manifest to file.
   *
   * @param manifest - manifest.
   * @param filePath - output file path.
   */
  public static saveAssemblyManifest(manifest: assembly.AssemblyManifest, filePath: string) {
    Manifest.saveManifest(manifest, filePath, ASSEMBLY_SCHEMA, Manifest.patchStackTagsOnWrite);
  }

  /**
   * Load and validates the cloud assembly manifest from file.
   *
   * @param filePath - path to the manifest file.
   */
  public static loadAssemblyManifest(filePath: string): assembly.AssemblyManifest {
    return Manifest.loadManifest(filePath, ASSEMBLY_SCHEMA, Manifest.patchStackTagsOnRead);
  }

  /**
   * Validates and saves the asset manifest to file.
   *
   * @param manifest - manifest.
   * @param filePath - output file path.
   */
  public static saveAssetManifest(manifest: assets.AssetManifest, filePath: string) {
    Manifest.saveManifest(manifest, filePath, ASSETS_SCHEMA, Manifest.patchStackTagsOnRead);
  }

  /**
   * Load and validates the asset manifest from file.
   *
   * @param filePath - path to the manifest file.
   */
  public static loadAssetManifest(filePath: string): assets.AssetManifest {
    return this.loadManifest(filePath, ASSETS_SCHEMA);
  }

  /**
   * Fetch the current schema version number.
   */
  public static version(): string {
    return SCHEMA_VERSION;
  }

  /**
   * Deprecated
   * @deprecated use `saveAssemblyManifest()`
   */
  public static save(manifest: assembly.AssemblyManifest, filePath: string) { return this.saveAssemblyManifest(manifest, filePath); }

  /**
   * Deprecated
   * @deprecated use `loadAssemblyManifest()`
   */
  public static load(filePath: string): assembly.AssemblyManifest { return this.loadAssemblyManifest(filePath); }

  private static validate(manifest: { version: string }, schema: jsonschema.Schema) {

    function parseVersion(version: string) {
      const ver = semver.valid(version);
      if (!ver) {
        throw new Error(`Invalid semver string: "${version}"`);
      }
      return ver;
    }

    const maxSupported = parseVersion(Manifest.version());
    const actual = parseVersion(manifest.version);

    // first validate the version should be accepted.
    if (semver.gt(actual, maxSupported)) {
      // we use a well known error prefix so that the CLI can identify this specific error
      // and print some more context to the user.
      throw new Error(`${VERSION_MISMATCH}: Maximum schema version supported is ${maxSupported}, but found ${actual}`);
    }

    // now validate the format is good.
    const validator = new jsonschema.Validator();
    const result = validator.validate(manifest, schema, {

      // does exist but is not in the TypeScript definitions
      nestedErrors: true,

      allowUnknownAttributes: false,

    } as any);
    if (!result.valid) {
      throw new Error(`Invalid assembly manifest:\n${result}`);
    }

  }

  private static saveManifest(manifest: any, filePath: string, schema: jsonschema.Schema, preprocess?: (obj: any) => any) {
    let withVersion = { ...manifest, version: Manifest.version() };
    Manifest.validate(withVersion, schema);
    if (preprocess) {
      withVersion = preprocess(withVersion);
    }
    fs.writeFileSync(filePath, JSON.stringify(withVersion, undefined, 2));
  }

  private static loadManifest(filePath: string, schema: jsonschema.Schema, preprocess?: (obj: any) => any) {
    let obj = JSON.parse(fs.readFileSync(filePath, { encoding: 'utf-8' }));
    if (preprocess) {
      obj = preprocess(obj);
    }
    Manifest.validate(obj, schema);
    return obj;
  }

  /**
   * This requires some explaining...
   *
   * We previously used `{ Key, Value }` for the object that represents a stack tag. (Notice the casing)
   * @link https://github.com/aws/aws-cdk/blob/v1.27.0/packages/aws-cdk/lib/api/cxapp/stacks.ts#L427.
   *
   * When that object moved to this package, it had to be JSII compliant, which meant the property
   * names must be `camelCased`, and not `PascalCased`. This meant it no longer matches the structure in the `manifest.json` file.
   * In order to support current manifest files, we have to translate the `PascalCased` representation to the new `camelCased` one.
   *
   * Note that the serialization itself still writes `PascalCased` because it relates to how CloudFormation expects it.
   *
   * Ideally, we would start writing the `camelCased` and translate to how CloudFormation expects it when needed. But this requires nasty
   * backwards-compatibility code and it just doesn't seem to be worth the effort.
   */
  private static patchStackTagsOnRead(manifest: assembly.AssemblyManifest) {
    return Manifest.replaceStackTags(manifest, tags => tags.map((diskTag: any) => ({
      key: diskTag.Key,
      value: diskTag.Value,
    })));
  }

  /**
   * See explanation on `patchStackTagsOnRead`
   *
   * Translate stack tags metadata if it has the "right" casing.
   */
  private static patchStackTagsOnWrite(manifest: assembly.AssemblyManifest) {
    return Manifest.replaceStackTags(manifest, tags => tags.map(memTag =>
      // Might already be uppercased (because stack synthesis generates it in final form yet)
      ('Key' in memTag ? memTag : { Key: memTag.key, Value: memTag.value }) as any,
    ));
  }

  /**
   * Recursively replace stack tags in the stack metadata
   */
  private static replaceStackTags(manifest: assembly.AssemblyManifest, fn: Endofunctor<assembly.StackTagsMetadataEntry>): assembly.AssemblyManifest {
    // Need to add in the `noUndefined`s because otherwise jest snapshot tests are going to freak out
    // about the keys with values that are `undefined` (even though they would never be JSON.stringified)
    return noUndefined({
      ...manifest,
      artifacts: mapValues(manifest.artifacts, artifact => {
        if (artifact.type !== assembly.ArtifactType.AWS_CLOUDFORMATION_STACK) { return artifact; }
        return noUndefined({
          ...artifact,
          metadata: mapValues(artifact.metadata, metadataEntries => metadataEntries.map(metadataEntry => {
            if (metadataEntry.type !== assembly.ArtifactMetadataEntryType.STACK_TAGS || !metadataEntry.data) { return metadataEntry; }
            return {
              ...metadataEntry,
              data: fn(metadataEntry.data as assembly.StackTagsMetadataEntry),
            };
          })),
        } as assembly.ArtifactManifest);
      }),
    });
  }

  private constructor() {}
}

type Endofunctor<A> = (x: A) => A;

function mapValues<A, B>(xs: Record<string, A> | undefined, fn: (x: A) => B): Record<string, B> | undefined {
  if (!xs) { return undefined; }
  const ret: Record<string, B> | undefined = {};
  for (const [k, v] of Object.entries(xs)) {
    ret[k] = fn(v);
  }
  return ret;
}

function noUndefined<A extends object>(xs: A): A {
  const ret: any = {};
  for (const [k, v] of Object.entries(xs)) {
    if (v !== undefined) {
      ret[k] = v;
    }
  }
  return ret;
}