feat(@angular-devkit/core): remove Log messages from Job API

If a system wants to have logging it should multiplex it itself on a channel.

Also changed the previous Architect commits to remove usage of Logs and move
to a "log" channel.

Author: hansl

Diff for: packages/angular_devkit/architect/src/create-builder.ts

@@ -5,7 +5,7 @@
  * Use of this source code is governed by an MIT-style license that can be
  * found in the LICENSE file at https://angular.io/license
  */
-import { experimental, isPromise, json } from '@angular-devkit/core';
+import { experimental, isPromise, json, logging } from '@angular-devkit/core';
 import { Observable, Subscription, from, isObservable, of } from 'rxjs';
 import { tap } from 'rxjs/operators';
 import {
@@ -17,6 +17,7 @@ import {
   BuilderProgressState,
   Target,
   TypedBuilderProgress,
+  targetStringFromTarget,
 } from './api';
 import { Builder, BuilderSymbol, BuilderVersionSymbol } from './internal';
 import { scheduleByName, scheduleByTarget } from './schedule-by-name';
@@ -28,13 +29,16 @@ export function createBuilder<OptT extends json.JsonObject>(
   const cjh = experimental.jobs.createJobHandler;
   const handler = cjh<json.JsonObject, BuilderInput, BuilderOutput>((options, context) => {
     const scheduler = context.scheduler;
-    const logger = context.logger;
     const progressChannel = context.createChannel('progress');
+    const logChannel = context.createChannel('log');
     let currentState: BuilderProgressState = BuilderProgressState.Stopped;
     let current = 0;
     let status = '';
     let total = 1;
 
+    function log(entry: logging.LogEntry) {
+      logChannel.next(entry);
+    }
     function progress(progress: TypedBuilderProgress, context: BuilderContext) {
       currentState = progress.state;
       if (progress.state === BuilderProgressState.Running) {
@@ -74,6 +78,13 @@ export function createBuilder<OptT extends json.JsonObject>(
 
       function onInput(i: BuilderInput) {
         const builder = i.info as BuilderInfo;
+        const loggerName = i.target
+          ? targetStringFromTarget(i.target as Target)
+          : builder.builderName;
+        const logger = new logging.Logger(loggerName);
+
+        subscriptions.push(logger.subscribe(entry => log(entry)));
+
         const context: BuilderContext = {
           builder,
           workspaceRoot: i.workspaceRoot,

Diff for: packages/angular_devkit/architect/src/schedule-by-name.ts

@@ -65,15 +65,16 @@ export async function scheduleByName(
     job.input.next(message);
   }
 
+  const logChannelSub = job.getChannel<logging.LogEntry>('log').subscribe(entry => {
+    logger.next(entry);
+  });
+
   const s = job.outboundBus.subscribe(
-    message => {
-      if (message.kind == experimental.jobs.JobOutboundMessageKind.Log) {
-        logger.log(message.entry.level, message.entry.message, message.entry);
-      }
-    },
+    undefined,
     undefined,
     () => {
       s.unsubscribe();
+      logChannelSub.unsubscribe();
       if (stateSubscription) {
         stateSubscription.unsubscribe();
       }

Diff for: packages/angular_devkit/core/src/experimental/jobs/README.md

@@ -19,10 +19,6 @@ The I/O model is like that of an executable, where the argument corresponds to a
 command line, the input channel to STDIN, the output channel to STDOUT, and the channels
 would be additional output streams.
 
-In addition, a `Job` has a logging channel that can be used to log messages to the user. The 
-code that schedules the job must listen for or forward these messages. You can think of those
-messages as STDERR.
-
 ## LifeCycle
 A `Job` goes through multiple LifeCycle messages before its completion;
 1. `JobState.Queued`. The job was queued and is waiting. This is the default state from the
@@ -162,8 +158,7 @@ export const add = jobs.createJobHandler<number[], number>(
 ```
 
 You can also return a Promise or an Observable, as jobs are asynchronous. This helper will set
-start and end messages appropriately, and will pass in a logger. It will also manage channels
-automatically (see below).
+start and end messages appropriately. It will also manage channels automatically (see below).
 
 A more complex job can be declared like this:
 
@@ -246,7 +241,6 @@ member of the `JobOutboundMessage<O>` interface dictates what kind of message it
     dependent jobs. `createJobHandler()` automatically send this message.
 1. `JobOutboundMessageKind.Pong`. The job should answer a `JobInboundMessageKind.Ping` message with
     this. Automatically done by `createJobHandler()`.
-1. `JobOutboundMessageKind.Log`. A logging message (side effect that should be shown to the user).
 1. `JobOutboundMessageKind.Output`. An `Output` has been generated by the job.
 1. `JobOutboundMessageKind.ChannelMessage`, `JobOutboundMessageKind.ChannelError` and
     `JobOutboundMessageKind.ChannelComplete` are used for output channels. These correspond to the

Diff for: packages/angular_devkit/core/src/experimental/jobs/api.ts

@@ -7,7 +7,6 @@
  */
 import { Observable, Observer } from 'rxjs';
 import { JsonObject, JsonValue, schema } from '../../json/index';
-import { LogEntry, LoggerApi } from '../../logger/index';
 import { DeepReadonly } from '../../utils/index';
 
 /**
@@ -135,7 +134,6 @@ export enum JobOutboundMessageKind {
   Pong = 'p',
 
   // Feedback messages.
-  Log = 'l',
   Output = 'o',
 
   // Channel specific messages.
@@ -172,14 +170,6 @@ export interface JobOutboundMessageStart extends JobOutboundMessageBase {
   readonly kind: JobOutboundMessageKind.Start;
 }
 
-/**
- * A logging message, supporting the logging.LogEntry.
- */
-export interface JobOutboundMessageLog extends JobOutboundMessageBase {
-  readonly kind: JobOutboundMessageKind.Log;
-  readonly entry: LogEntry;
-}
-
 /**
  * An output value is available.
  */
@@ -274,7 +264,6 @@ export interface JobOutboundMessagePong extends JobOutboundMessageBase {
 export type JobOutboundMessage<OutputT extends JsonValue> =
   JobOutboundMessageOnReady
   | JobOutboundMessageStart
-  | JobOutboundMessageLog
   | JobOutboundMessageOutput<OutputT>
   | JobOutboundMessageChannelCreate
   | JobOutboundMessageChannelMessage
@@ -381,11 +370,6 @@ export interface Job<
  * Options for scheduling jobs.
  */
 export interface ScheduleJobOptions {
-  /**
-   * Where should logging be passed in. By default logging will be dropped.
-   */
-  logger?: LoggerApi;
-
   /**
    * Jobs that need to finish before scheduling this job. These dependencies will be passed
    * to the job itself in its context.

Diff for: packages/angular_devkit/core/src/experimental/jobs/architecture.md

@@ -101,7 +101,6 @@ and output values (STDOUT) as well as diagnostic (STDERR). They can be plugged o
 
                               ,______________________   
     JobInboundMessage<I> --> | handler(argument: A) |  --> JobOutboundMessage<O>
-                              `⎻⎻⎻⎻⎻⎻⎻⎻⎻⎻⎻⎻⎻⎻⎻⎻⎻⎻⎻⎻⎻⎻       - JobOutboundMessageKind.Log
                                                             - JobOutboundMessageKind.Output
                                                             - ...
 ```
@@ -129,7 +128,6 @@ and output values (STDOUT) as well as diagnostic (STDERR). They can be plugged o
     unblock dependent jobs. `createJobHandler()` automatically send this message.
 1. `JobOutboundMessageKind.Pong`. The job should answer a `JobInboundMessageKind.Ping` message with
     this. Automatically done by `createJobHandler()`.
-1. `JobOutboundMessageKind.Log`. A logging message (side effect that should be shown to the user).
 1. `JobOutboundMessageKind.Output`. An `Output` has been generated by the job.
 1. `JobOutboundMessageKind.ChannelMessage`, `JobOutboundMessageKind.ChannelError` and
     `JobOutboundMessageKind.ChannelComplete` are used for output channels. These correspond to
@@ -251,7 +249,7 @@ example would be an operator that takes a module path and run the job from that
 process. Or even a separate server, using HTTP calls.
 
 Another limitation is that the boilerplate is complex. Manually managing start/end life cycle, and
-other messages such as logging, etc. is tedious and requires a lot of code. A good way to keep
+other messages such as ping/pong, etc. is tedious and requires a lot of code. A good way to keep
 this limitation under control is to provide helpers to create `JobHandler`s which manage those
 messages for the developer. A simple handler could be to get a `Promise` and return the output of
 that promise automatically.

Diff for: packages/angular_devkit/core/src/experimental/jobs/create-job-handler.ts

@@ -10,7 +10,7 @@ import { Observable, Observer, Subject, Subscription, from, isObservable, of } f
 import { switchMap, tap } from 'rxjs/operators';
 import { BaseException } from '../../exception/index';
 import { JsonValue } from '../../json/index';
-import { Logger, LoggerApi } from '../../logger/index';
+import { LoggerApi } from '../../logger';
 import { isPromise } from '../../utils/index';
 import {
   JobDescription,
@@ -37,7 +37,6 @@ export interface SimpleJobHandlerContext<
   I extends JsonValue,
   O extends JsonValue,
 > extends JobHandlerContext<A, I, O> {
-  logger: LoggerApi;
   createChannel: (name: string) => Observer<JsonValue>;
   input: Observable<I>;
 }
@@ -100,23 +99,12 @@ export function createJobHandler<A extends JsonValue, I extends JsonValue, O ext
         }
       });
 
-      // Configure a logger to pass in as additional context.
-      const logger = new Logger('-internal-job-logger-');
-      const logSub = logger.subscribe(entry => {
-        subject.next({
-          kind: JobOutboundMessageKind.Log,
-          description,
-          entry,
-        });
-      });
-
       // Execute the function with the additional context.
       const channels = new Map<string, Subject<JsonValue>>();
 
       const newContext: SimpleJobHandlerContext<A, I, O> = {
         ...context,
         input: inputChannel.asObservable(),
-        logger,
         createChannel(name: string) {
           if (channels.has(name)) {
             throw new ChannelAlreadyExistException(name);
@@ -164,7 +152,6 @@ export function createJobHandler<A extends JsonValue, I extends JsonValue, O ext
         () => complete(),
       );
       subscription.add(inboundSub);
-      subscription.add(logSub);
 
       return subscription;
     });

Diff for: packages/angular_devkit/core/src/experimental/jobs/simple-scheduler.ts

@@ -22,13 +22,12 @@ import {
   filter,
   first,
   ignoreElements,
-  map, share,
+  map,
   shareReplay,
   switchMap,
   tap,
 } from 'rxjs/operators';
 import { JsonValue, schema } from '../../json';
-import { NullLogger } from '../../logger';
 import {
   Job,
   JobDescription,
@@ -305,8 +304,6 @@ export class SimpleScheduler<
     let state = JobState.Queued;
     let pingId = 0;
 
-    const logger = options.logger ? options.logger : new NullLogger();
-
     // Create the input channel by having a filter.
     const input = new Subject<JsonValue>();
     input.pipe(
@@ -348,11 +345,6 @@ export class SimpleScheduler<
         state = this._updateState(message, state);
 
         switch (message.kind) {
-          case JobOutboundMessageKind.Log:
-            const entry = message.entry;
-            logger.log(entry.level, entry.message, entry);
-            break;
-
           case JobOutboundMessageKind.ChannelCreate: {
             const maybeSubject = channelsSubject.get(message.name);
             // If it doesn't exist or it's closed on the other end.