Count the number of packages on pub.dev that uses package:mono_repo.

count_mono_repo_pub_packages.dart

// Copyright 2019 Google LLC.
// SPDX-License-Identifier: Apache-2.0

import 'dart:async' show FutureOr;
import 'dart:async';
import 'dart:convert' show utf8, json;
import 'dart:io' show Directory, Process, IOException, File;
import 'package:http/http.dart' as http;
import 'package:retry/retry.dart' show retry;
import 'package:pool/pool.dart' show Pool;

const _userAgent = 'bot-jonasfj-pub-analysis/1.0 (+jopsen@gmail.com)';
const _pubServer = 'https://pub.dartlang.org';

Future<List<int>> _get(String url) => retry(() async {
      final response = await http.get(url, headers: {
        'User-Agent': _userAgent,
      }).timeout(Duration(minutes: 3));
      if (200 >= response.statusCode && response.statusCode < 200)
        throw Exception('Expected 2xx response, got ${response.statusCode}');
      return response.bodyBytes;
    },
        retryIf: (e) =>
            e is IOException ||
            e is TimeoutException ||
            e.toString().contains('Expected 2xx'));

dynamic _decodeJson(List<int> data) => json.fuse(utf8).decode(data) as dynamic;

Future<List<String>> listAllPackages() async {
  final body = await _get('$_pubServer/api/packages?compact=1');
  return _decodeJson(body)['packages'].cast<String>();
}

Future<List<String>> listPackageVersions(String package) async {
  final body = await _get('$_pubServer/api/packages/$package');
  return _decodeJson(body)['versions']
      .map<String>((v) => v['version'] as String)
      .toList();
}

Future<String> latestPackageVersion(String package) async {
  final body = await _get('$_pubServer/api/packages/$package');
  return _decodeJson(body)['latest']['version'] as String;
}

String packageUrl(String package, String version) =>
    '$_pubServer/packages/$package/versions/$version.tar.gz';

Future<void> getPackage(String package, String version, String target) async {
  final tar = await Process.start('tar', ['zxC', target]);
  tar.stdin.add(await _get(packageUrl(package, version)));
  await tar.stdin.close();
  if (await tar.exitCode != 0) {
    throw Exception('Failed to extract downloaded package data');
  }
}

Future<T> withPackage<T>(
  String package,
  String version,
  FutureOr<T> Function(Directory) fn,
) async {
  final temp = await Directory.systemTemp.createTemp('pkg-');
  try {
    await getPackage(package, version, temp.path).timeout(Duration(minutes: 7));
    return await fn(temp);
  } finally {
    await temp.delete(recursive: true);
  }
}

Future<void> main() async {
  List<String> usesMonoRepo = [];
  print('# Analyzing all packages');
  final allPackages = await listAllPackages();
  int failedPackages = 0;
  final pool = Pool(50, timeout: Duration(minutes: 20));
  await Future.wait(allPackages.map((pkg) => pool.withResource(() async {
        try {
          await withPackage(pkg, await latestPackageVersion(pkg), (f) async {
            if (await File.fromUri(f.uri.resolve('mono_pkg.yaml')).exists()) {
              print('- $pkg contains mono_pkg.yaml');
              usesMonoRepo.add(pkg);
            } else {
              print('- $pkg checked');
            }
          });
        } catch (e) {
          print('- $pkg failed: $e');
          failedPackages++;
        }
      })));
  print('# Packages using mono_repo:');
  usesMonoRepo.forEach((p) => print('- $p'));
  print('Total number of packages using mono_repo:');
  print('  ${usesMonoRepo.length} of ${allPackages.length} packages analyzed');
  print('  Failed analysis of $failedPackages packages');
}

pubspec.yaml

name: count_mono_repo_pub_packages
publish_to: none
dependencies:
  http: ^0.12.0
  retry: ^3.0.0
  pool: ^1.4.0