Remove try from future.

Bug:
Change-Id: I4e003bfa1cccbb8445450d2e897037b8dd7dc941
Reviewed-on: https://dart-review.googlesource.com/10940
Reviewed-by: William Hesse <whesse@google.com>

tools/gardening/lib/src/cache_new.dart

@@ -5,7 +5,7 @@
 import 'dart:async';
 import 'dart:io';
 import 'logger.dart';
-import 'try.dart';
+import 'util.dart';
 
 typedef Future<String> FetchDataFunction();
 typedef Future<String> WithCacheFunction(FetchDataFunction fetchData,
@@ -26,21 +26,15 @@ CreateCacheFunction initCache(Uri baseUri, [Logger logger]) {
       if (overrideKey != null) {
         key = overrideKey;
       }
-
       if (key == null || key.isEmpty) {
         logger.warning("Key is null or empty - cannot cache result");
       } else {
         // format key
         key = key.replaceAll("/", "_").replaceAll(".", "_");
-
-        Try<CacheResult> readResult = await cache.read(key, duration);
-        if (!readResult.isError && readResult.value.hasResult) {
+        var cacheResult = await cache.read(key, duration);
+        if (cacheResult.hasResult) {
           logger.debug("Found key $key in cache");
-          return readResult.value.result;
-        }
-        if (readResult.isError) {
-          logger.error("Error when reading from cache", readResult.error,
-              readResult.stackTrace);
+          return cacheResult.result;
         }
       }
 
@@ -93,32 +87,35 @@ class Cache {
   }
 
   /// Try reading [path] from cache
-  Future<Try<CacheResult>> read(String path, [Duration duration]) async {
+  Future<CacheResult> read(String path, [Duration duration]) async {
     if (memoryCache.containsKey(path)) {
       logger.debug('Found $path in memory cache');
-      return new Try.from(new CacheResult(memoryCache[path]));
+      return new CacheResult(memoryCache[path]);
     }
 
     File file = new File.fromUri(base.resolve(path));
 
-    if (!(await file.exists())) {
+    if (!await file.exists()) {
       logger.debug('Could not find file $path in file cache');
-      return new Try.from(new CacheResult.noResult());
+      return new CacheResult.noResult();
     }
-
     if (duration != null &&
         new DateTime.now().difference(await file.lastModified()) > duration) {
       logger.debug('File $path was found but the information is too stale,'
           'for the duration: $duration');
-      return new Try.from(new CacheResult.noResult());
+      return new CacheResult.noResult();
     }
 
-    return tryStartAsync(() async {
-      logger.debug('Found $path in file cache');
-      var text = await file.readAsString();
+    logger.debug('Found $path in file cache');
+
+    try {
+      String text = await file.readAsString();
       memoryCache[path] = text;
       return new CacheResult(text);
-    });
+    } catch (error, st) {
+      logger.error("Could not read $path:", error, st);
+      return new CacheResult.noResult();
+    }
   }
 
   /// Store [text] as the cache data for [path].

tools/gardening/lib/src/compare_failures_impl.dart

@@ -16,7 +16,6 @@ import 'cache_new.dart';
 import 'logger.dart';
 import 'luci_api.dart' hide Timing;
 import 'luci.dart';
-import 'try.dart';
 import 'util.dart';
 
 Future mainInternal(Bot bot, List<String> args,
@@ -51,22 +50,16 @@ Future<Map<BuildUri, List<BuildResult>>> loadBuildResults(
     Logger logger = createLogger(verbose: verbose);
     CreateCacheFunction createCache =
         createCacheFunction(logger, disableCache: noCache);
-    Try<List<BuildDetail>> tryBuildDetails = await fetchBuildsForCommmit(
+    buildDetails = await fetchBuildsForCommmit(
         luci, logger, DART_CLIENT, commit, createCache, 25);
-    tryBuildDetails.fold(exceptionPrint('Failed to fetch commits.'),
-        (List<BuildDetail> result) {
-      if (result.isEmpty) {
-        print('No builds found for $commit');
-      } else {
-        buildDetails = result;
-        if (verbose) {
-          log('Found builds for commit $commit:');
-          buildDetails.forEach((b) => log(' ${b.botName}: ${b.buildNumber}'));
-        } else {
-          print('Found ${buildDetails.length} builds for commit $commit.');
-        }
-      }
-    });
+    if (buildDetails.isEmpty) {
+      print('No builds found for $commit');
+    } else if (verbose) {
+      log('Found builds for commit $commit:');
+      buildDetails.forEach((b) => log(' ${b.botName}: ${b.buildNumber}'));
+    } else {
+      print('Found ${buildDetails.length} builds for commit $commit.');
+    }
   }
 
   BuildUri updateWithCommit(BuildUri buildUri) {

tools/gardening/lib/src/luci.dart

@@ -3,7 +3,6 @@
 // BSD-style license that can be found in the LICENSE file.
 
 import 'dart:async';
-import 'try.dart';
 import 'logger.dart';
 import 'cache_new.dart';
 import 'luci_api.dart';
@@ -19,49 +18,46 @@ const String DART_CLIENT = 'client.dart';
 
 /// Fetches all builds for a given [commit]-hash, by searching the latest
 /// [amount] builds.
-Future<Try<List<BuildDetail>>> fetchBuildsForCommmit(
-    LuciApi luciApi,
-    Logger logger,
-    String client,
-    String commit,
-    CreateCacheFunction createCache,
-    [int amount = 1]) async {
+Future<List<BuildDetail>> fetchBuildsForCommmit(LuciApi luciApi, Logger logger,
+    String client, String commit, CreateCacheFunction createCache,
+    [int amount = 1]) {
   logger.info(
       "Sorry - this is going to take some time, since we have to look into all "
       "$amount latest builds for all bots for client ${client}.\n"
       "Subsequent queries run faster if caching is not turned off...");
 
   logger.debug("Finding primary bots for client $client");
-  var buildBots = await getPrimaryBuilders(
+  var futureBuildBots = getPrimaryBuilders(
       luciApi, client, createCache(duration: new Duration(minutes: 30)));
 
   var cache = createCache(duration: new Duration(minutes: 30));
 
-  return (await buildBots.bindAsync((buildBots) async {
+  return futureBuildBots.then((buildBots) {
     var buildBotBuilds = new List<List<BuildDetail>>();
-    for (var buildBot in buildBots) {
-      (await luciApi.getBuildBotDetails(client, buildBot, cache, amount)).fold(
-          (ex, st) {
-        logger.error("Problem getting results", ex, st);
-      }, buildBotBuilds.add);
-    }
-    logger.debug("All latest $amount builds found for client $client. "
-        "Processing results...");
-    return buildBotBuilds.expand((id) => id).toList();
-  })).bind((buildDetails) {
-    return buildDetails.where((BuildDetail buildDetail) {
-      return buildDetail.allChanges
-          .any((change) => change.revision.startsWith(commit));
-    }).toList();
+    var futureDetails = buildBots.map((buildBot) {
+      return luciApi
+          .getBuildBotDetails(client, buildBot, cache, amount)
+          .then(buildBotBuilds.add)
+          .catchError(
+              errorLogger(logger, "Could not get details for $buildBot", []));
+    });
+    return Future.wait(futureDetails).then((details) {
+      return buildBotBuilds.expand((id) => id);
+    }).then((details) {
+      return details.where((buildDetail) {
+        return buildDetail.allChanges
+            .any((change) => change.revision.startsWith(commit));
+      }).toList();
+    });
   });
 }
 
 /// [getBuilderGroups] fetches all builder groups not in -dev, -stable and
 /// -integration from CBE.
-Future<Try<List<String>>> getBuilderGroups(
-    LuciApi luciApi, String client, WithCacheFunction withCache) async {
-  var result = await luciApi.getJsonFromChromeBuildExtract(client, withCache);
-  return result.bind((json) {
+Future<List<String>> getBuilderGroups(
+    LuciApi luciApi, String client, WithCacheFunction withCache) {
+  var result = luciApi.getJsonFromChromeBuildExtract(client, withCache);
+  return result.then((json) {
     var builders = json["builders"];
     return builders.keys.fold<Map<String, Object>>({},
         (Map<String, Object> map, builderKey) {
@@ -75,19 +71,19 @@ Future<Try<List<String>>> getBuilderGroups(
 }
 
 /// [getAllBuilders] fetches all builders from CBE.
-Future<Try<List<String>>> getAllBuilders(
-    LuciApi luciApi, String client, WithCacheFunction withCache) async {
-  var result = await luciApi.getJsonFromChromeBuildExtract(client, withCache);
-  return result.bind((json) {
+Future<List<String>> getAllBuilders(
+    LuciApi luciApi, String client, WithCacheFunction withCache) {
+  var result = luciApi.getJsonFromChromeBuildExtract(client, withCache);
+  return result.then((json) {
     return json["builders"].keys;
   });
 }
 
 /// [getPrimaryBuilders] fetches all primary builders from CBE.
-Future<Try<List<String>>> getPrimaryBuilders(
-    LuciApi luciApi, String client, WithCacheFunction withCache) async {
-  var result = await getAllBuilders(luciApi, client, withCache);
-  return result.bind((builders) {
+Future<List<String>> getPrimaryBuilders(
+    LuciApi luciApi, String client, WithCacheFunction withCache) {
+  var result = getAllBuilders(luciApi, client, withCache);
+  return result.then((builders) {
     return builders
         .where((builderKey) =>
             !UNINTERESTING_BUILDER_SUFFIXES.any((x) => builderKey.contains(x)))
@@ -96,13 +92,13 @@ Future<Try<List<String>>> getPrimaryBuilders(
 }
 
 /// [getPrimaryBuilders] gets all builders in builder group [builderGroup].
-Future<Try<List<String>>> getBuildersInBuilderGroup(LuciApi luciApi,
-    String client, WithCacheFunction withCache, String builderGroup) async {
-  var result = await luciApi.getJsonFromChromeBuildExtract(client, withCache);
-  return result.bind((json) {
+Future<List<String>> getBuildersInBuilderGroup(LuciApi luciApi, String client,
+    WithCacheFunction withCache, String builderGroup) {
+  var result = luciApi.getJsonFromChromeBuildExtract(client, withCache);
+  return result.then((json) {
     var builders = json["builders"];
     return builders.keys.where((builder) {
       return sanitizeCategory(builders[builder]["category"]) == builderGroup;
-    });
+    }).toList();
   });
 }

tools/gardening/lib/src/luci_api.dart

@@ -7,7 +7,6 @@ import 'dart:async';
 import 'dart:convert';
 import 'package:http/http.dart' as http;
 import 'package:archive/archive.dart';
-import 'try.dart';
 import 'cache_new.dart';
 
 const String LUCI_HOST = "luci-milo.appspot.com";
@@ -28,30 +27,32 @@ class LuciApi {
 
   /// [getJsonFromChromeBuildExtract] gets json from Cbe, with information
   /// about all bots and current builds.
-  Future<Try<dynamic>> getJsonFromChromeBuildExtract(
+  Future<dynamic> getJsonFromChromeBuildExtract(
       String client, WithCacheFunction withCache) async {
-    var result = await tryStartAsync(() => withCache(
-        () => _makeGetRequest(new Uri(
-            scheme: 'https', host: CBE_HOST, path: "/get_master/${client}")),
-        "cbe"));
-    return result.bind((str) => JSON.decode(str));
+    return withCache(
+            () => _makeGetRequest(new Uri(
+                scheme: 'https',
+                host: CBE_HOST,
+                path: "/get_master/${client}")),
+            "cbe")
+        .then(JSON.decode);
   }
 
   /// [getMaster] fetches master information for all bots.
-  Future<Try<Object>> getMaster(
-      String client, WithCacheFunction withCache) async {
+  Future<dynamic> getMaster(String client, WithCacheFunction withCache) async {
     var uri = new Uri(
         scheme: "https",
         host: LUCI_HOST,
         path: "prpc/milo.Buildbot/GetCompressedMasterJSON");
     var body = {"name": client};
-    var result = await tryStartAsync(() => withCache(
-        () => _makePostRequest(uri, JSON.encode(body), {
-              HttpHeaders.CONTENT_TYPE: "application/json",
-              HttpHeaders.ACCEPT: "application/json"
-            }),
-        '${uri.path}'));
-    return result.bind((str) => JSON.decode(str)).bind((json) {
+    return withCache(
+            () => _makePostRequest(uri, JSON.encode(body), {
+                  HttpHeaders.CONTENT_TYPE: "application/json",
+                  HttpHeaders.ACCEPT: "application/json"
+                }),
+            '${uri.path}')
+        .then(JSON.decode)
+        .then((json) {
       var data = JSON.decode(UTF8
           .decode(new GZipDecoder().decodeBytes(BASE64.decode(json["data"]))));
       return data;
@@ -60,7 +61,7 @@ class LuciApi {
 
   /// Calling the Milo Api to get latest builds for this bot,
   /// where the field [amount] is the number of recent builds to fetch.
-  Future<Try<List<BuildDetail>>> getBuildBotDetails(
+  Future<List<BuildDetail>> getBuildBotDetails(
       String client, String botName, WithCacheFunction withCache,
       [int amount = 20]) async {
     var uri = new Uri(
@@ -73,13 +74,14 @@ class LuciApi {
       "limit": amount,
       "includeCurrent": true
     };
-    var result = await tryStartAsync(() => withCache(
-        () => _makePostRequest(uri, JSON.encode(body), {
-              HttpHeaders.CONTENT_TYPE: "application/json",
-              HttpHeaders.ACCEPT: "application/json"
-            }),
-        '${uri.path}_${botName}_$amount'));
-    return result.bind((str) => JSON.decode(str)).bind((json) {
+    return withCache(
+            () => _makePostRequest(uri, JSON.encode(body), {
+                  HttpHeaders.CONTENT_TYPE: "application/json",
+                  HttpHeaders.ACCEPT: "application/json"
+                }),
+            '${uri.path}_${botName}_$amount')
+        .then(JSON.decode)
+        .then((json) {
       return json["builds"].map((b) {
         var build = JSON.decode(UTF8.decode(BASE64.decode(b["data"])));
         return getBuildDetailFromJson(client, botName, build);
@@ -89,20 +91,21 @@ class LuciApi {
 
   /// Calling the Milo Api to get information about a specific build
   /// where the field [buildNumber] is the build number to fetch.
-  Future<Try<BuildDetail>> getBuildBotBuildDetails(String client,
-      String botName, int buildNumber, WithCacheFunction withCache) async {
+  Future<BuildDetail> getBuildBotBuildDetails(String client, String botName,
+      int buildNumber, WithCacheFunction withCache) async {
     var uri = new Uri(
         scheme: "https",
         host: LUCI_HOST,
         path: "prpc/milo.Buildbot/GetBuildbotBuildJSON");
     var body = {"master": client, "builder": botName, "buildNum": buildNumber};
-    var result = await tryStartAsync(() => withCache(
-        () => _makePostRequest(uri, JSON.encode(body), {
-              HttpHeaders.CONTENT_TYPE: "application/json",
-              HttpHeaders.ACCEPT: "application/json"
-            }),
-        '${uri.path}_${botName}_$buildNumber'));
-    return result.bind((str) => JSON.decode(str)).bind((json) {
+    return withCache(
+            () => _makePostRequest(uri, JSON.encode(body), {
+                  HttpHeaders.CONTENT_TYPE: "application/json",
+                  HttpHeaders.ACCEPT: "application/json"
+                }),
+            '${uri.path}_${botName}_$buildNumber')
+        .then(JSON.decode)
+        .then((json) {
       var build = JSON.decode(UTF8.decode(BASE64.decode(json["data"])));
       return getBuildDetailFromJson(client, botName, build);
     });

tools/gardening/lib/src/try.dart

@@ -30,17 +30,6 @@ class Try<T> {
     }
   }
 
-  Future<Try<S>> bindAsync<S>(Future<S> f(T x)) async {
-    if (_err != null) {
-      return new Try.fail(_err, _stackTrace);
-    }
-    try {
-      return new Try.from(await f(_val));
-    } catch (ex, stackTrace) {
-      return new Try.fail(ex, stackTrace);
-    }
-  }
-
   void fold(void caseErr(dynamic ex, StackTrace st), void caseVal(T x)) {
     if (_err != null) {
       caseErr(_err, _stackTrace);
@@ -49,18 +38,9 @@ class Try<T> {
     }
   }
 
-  Future foldAsync(
-      Future caseErr(dynamic ex, StackTrace st), Future caseVal(T x)) async {
-    if (_err != null) {
-      await caseErr(_err, _stackTrace);
-    } else {
-      await caseVal(_val);
-    }
-  }
-
   bool get isError => _err != null;
 
-  Exception get error => _err;
+  Error get error => _err;
   StackTrace get stackTrace => _stackTrace;
 
   T get value => _val;
@@ -71,7 +51,3 @@ class Try<T> {
 Try<T> tryStart<T>(T action()) {
   return new Try<int>.from(0).bind<T>((dummy) => action());
 }
-
-Future<Try<T>> tryStartAsync<T>(Future<T> action()) {
-  return new Try<int>.from(0).bindAsync<T>((dummy) => action());
-}