Ben Konyi
5536951738
This change reworks the client resume permissions API to make it easier
for clients to deal with user provided `--pause-isolates-on-start` and
`--pause-isolates-on-exit` flags.
`requireUserPermissionToResume` should be called by the tool that
launches the Dart process to indicate whether or not the user provided
`--pause-isolates-on-{start,exit}`. The default behavior is to assume
that a tool set these flags for its own use (e.g., resetting breakpoints
after a hot restart in Flutter), where isolates will resume immediately
after each client that has indicated interest in that pause event has
invoked `readyToResume`.
If a user provided one of the previously mentioned flags, isolates will
not immediately resume after each relevant client has invoked
`readyToResume`. Instead, a call to `resume()` must be made to indicate
the user has triggered the resume request instead of tooling. If the
user permissions to resume are changed while the isolate is paused and
all relevant clients have invoked `readyToResume`, the isolate will
automatically resume if the user no longer requires us to wait for a
user resume.
`resume()` now also acts as a "force resume", bypassing any required
permissions set by tooling.
This behavior change is breaking, so the DDS protocol version is being
bumped to 2.0.
`package:dds_service_extensions` has also been updated to include the
following DDS RPCs:
- `requireUserPermissionToResume`
- `readyToResume`
Change-Id: Id5f0806b3c56507d39eb00b6305b8896bab13ae7
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/357420
Reviewed-by: Elliott Brooks <elliottbrooks@google.com>
Commit-Queue: Ben Konyi <bkonyi@google.com>
A package used to spawn the Dart Developer Service (DDS), which is used to communicate with a Dart VM Service instance and provide extended functionality to the core VM Service Protocol.
Functionality
Existing VM Service clients can issue both HTTP, websocket, and SSE requests to a running DDS instance as if it were an instance of the VM Service itself. If a request corresponds to an RPC defined in the VM Service Protocol, DDS will forward the request and return the response from the VM Service. Requests corresponding to an RPC defined in the DDS Protocol will be handled directly by the DDS instance.
SSE Support
For certain web clients it may be preferable or required to communicate with DDS using server-sent events (SSE). DDS has an SSE handler listening for requests on /$debugHandler.
SSE and package:vm_service example
import 'package:sse/sse.dart';
import 'package:vm_service/vm_service.dart';
void main() {
// Establish connection with DDS using SSE.
final ddsChannel = SseClient('${ddsUri}\$debugHandler');
// Wait for ddsChannel to be established
await ddsChannel.onOpen.first;
// Initialize VmService using the sink and stream from ddsChannel.
final vmService = VmService(
ddsChannel.stream,
(e) => ddsChannel.sink.add(e),
);
// You're ready to query DDS and the VM service!
print(await vmService.getVersion());
}
Debugging DDS
One way to get stdout from files in DDS while debugging is to log messages to a file. You can add a method such as:
void _fileLog(String message) {
final file = File('/tmp/dds.log');
if (!file.existsSync()) {
file.createSync();
}
file.writeAsStringSync(
'''
$message
''',
mode: FileMode.append,
);
}
Then you can call _fileLog('some print debugging message'), and the log message will be written to a temp file.
To get logging output in real time, run tail -f /tmp/dds.log.