Recent optimizations to ngcc have significantly reduced the total time
it takes to process `node_modules`, to such extend that sharding across
multiple processes has become less effective. Previously, running
ngcc asynchronously would allow for up to 8 workers to be allocated,
however these workers have to repeat work that could otherwise be shared.
Because ngcc is now able to reuse more shared computations, the overhead
of multiple workers is increased and therefore becomes less effective.
As an additional benefit, having fewer workers requires less memory and
less startup time.
To give an idea, using the following test setup:
```bash
npx @angular/cli new perf-test
cd perf-test
yarn ng add @angular/material
./node_modules/.bin/ngcc --properties es2015 module main \
--first-only --create-ivy-entry-points
```
We observe the following figures on CI:
| | 10.1.1 | PR #38840 |
| ----------------- | --------- | --------- |
| Sync | 85s | 25s |
| Async (8 workers) | 22s | 16s |
| Async (4 workers) | - | 11s |
In addition to changing the default number of workers, ngcc will now
use the environment variable `NGCC_MAX_WORKERS` that may be configured
to either reduce or increase the number of workers.
PR Close#38840
In CLI v10 there was a move to use the new solution-style tsconfig
which became available in TS 3.9.
The result of this is that the standard tsconfig.json no longer contains
important information such as "paths" mappings, which ngcc might need to
correctly compute dependencies.
ngcc (and ngc and tsc) infer the path to tsconfig.json if not given an
explicit tsconfig file-path. But now that means it infers the solution
tsconfig rather than one that contains the useful information it used to
get.
This commit logs a warning in this case to inform the developer
that they might not have meant to load this tsconfig and offer
alternative options.
Fixes#36386
PR Close#38003
The `Logger` interface and its related classes are general purpose
and could be used by other tooling. Moving it into ngtsc is a more
suitable place from which to share it - similar to the FileSystem stuff.
PR Close#37114
This finder is designed to only process entry-points that are reachable
by the program defined by a tsconfig.json file.
It is triggered by calling `mainNgcc()` with the `findEntryPointsFromTsConfigProgram`
option set to true. It is ignored if a `targetEntryPointPath` has been
provided as well.
It is triggered from the command line by adding the `--use-program-dependencies`
option, which is also ignored if the `--target` option has been provided.
Using this option can speed up processing in cases where there is a large
number of dependencies installed but only a small proportion of the
entry-points are actually imported into the application.
PR Close#37075
This commit will store a cached copy of the parsed tsconfig
that can be reused if the tsconfig path is the same.
This will improve the ngcc "noop" case, where there is no processing
to do, when the entry-points have already been processed.
Previously we were parsing this config every time we checked for
entry-points to process, which can take up to seconds in some
cases.
Resolves#36882
PR Close#37417
Now that `ngcc/src/ngcc_options` imports `FileWriter` type, there is a
circular dependency detected by the `ts-circular-deps:check` lint check:
```
ngcc/src/ngcc_options.ts
→ ngcc/src/writing/file_writer.ts
→ ngcc/src/packages/entry_point_bundle.ts
→ ngcc/src/ngcc_options.ts
```
This commit moves the `PathMappings` type (and related helpers) to a
separate file to avoid the circular dependency.
NOTE:
The circular dependency was only with taking types into account. There
was no circular dependency for the actual (JS) code.
PR Close#36626
Previously, when running in parallel mode and a worker process crashed
while processing a task, it was not possible for ngcc to continue
without risking ending up with a corrupted entry-point and therefore it
exited with an error. This, for example, could happen when a worker
process received a `SIGKILL` signal, which was frequently observed in CI
environments. This was probably the result of Docker killing processes
due to increased memory pressure.
One factor that amplifies the problem under Docker (which is often used
in CI) is that it is not possible to distinguish between the available
CPU cores on the host machine and the ones made available to Docker
containers, thus resulting in ngcc spawning too many worker processes.
This commit addresses these issues in the following ways:
1. We take advantage of the fact that files are written to disk only
after an entry-point has been fully analyzed/compiled. The master
process can now determine whether a worker process has not yet
started writing files to disk (even if it was in the middle of
processing a task) and just put the task back into the tasks queue if
the worker process crashes.
2. The master process keeps track of the transformed files that a worker
process will attempt to write to disk. If the worker process crashes
while writing files, the master process can revert any changes and
put the task back into the tasks queue (without risking corruption).
3. When a worker process crashes while processing a task (which can be a
result of increased memory pressure or too many worker processes),
the master process will not try to re-spawn it. This way the number
or worker processes is gradually adjusted to a level that can be
accomodated by the system's resources.
Examples of ngcc being able to recover after a worker process crashed:
- While idling: https://circleci.com/gh/angular/angular/682197
- While compiling: https://circleci.com/gh/angular/angular/682209
- While writing files: https://circleci.com/gh/angular/angular/682267
Jira issue: [FW-2008](https://angular-team.atlassian.net/browse/FW-2008)
Fixes#36278
PR Close#36626
