Files
sdk/runtime/bin
jonahwilliams 96ff3276f4 [vmservice] allow fallback on port bind failure
Work towards https://github.com/flutter/flutter/issues/46724

Background:

on the latest versions of iOS today, we have to use mdns to discover the observatory port and authentication code. For a variety of reasons this can fail, leaving us with no way to connect.

An alternative approach is to specify the observatory port and disable the authentication code. If binding to this port fails, however, we would still like to attempt connecting with mdns.

Overview:

This adds a new flag to the dart SDK, --enable-service-port-fallback. This amends the behavior of the vmservice with a specified port. After failing to bind 3 times to a non-zero port, update the port selection to 0.

Results:

Tested locally two dart VMs with the same specified port:

```
jonahwilliams@jonahwilliams0:~/Documents/engine/src/out/host_debug_unopt$ ./dart --enable-service-port-fallback --observe=8080 example.dart
Observatory server failed to start after 1 tries
Falling back to automatic port selection

vm-service: isolate(2785434094928835)  'main' has no debugger attached and is paused at exit.  Connect to Observatory to debug.
Observatory listening on http://127.0.0.1:45663/62A5IHjmv9E=/
```
Change-Id: I582ab402a457330928e5b490f9718fcd52b56720
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/133434
Reviewed-by: Ben Konyi <bkonyi@google.com>
Commit-Queue: Jonah Williams <jonahwilliams@google.com>
2020-01-28 23:36:14 +00:00
..
2018-01-18 16:38:54 +00:00
2018-05-03 17:59:44 +00:00