When using the Dart Docker images hosted on hub.docker.com (https://registry.hub.docker.com/search?q=google%2Fdart) it is currently not possible to use the Dart Editor to debug code running inside.

For the images google/dart-runtime and google/dart-hello enabling the debugger in the Dart VM can be done by passing the environment variable DBG_ENABLE when starting the container. So with a working docker installation (e.g. boot2docker) enabling the debugger for the google/dart-hello sample:

$ docker run -d -p 8080:8080 -p 5858:5858 --env DBG_ENABLE=1 google/dart-hello

(first time this is run a Docker images will be downloaded, so it will take some time).

This also prints out the container ID.

As expected this will stall the Dart VM in the container before main, so that application in the container is not running.

Check out https://github.com/dart-lang/dart_docker which have the source code to the application, and set a breakpoint in the server code in dart_docker/hello/bin/server.dart.

Now connect to the VM inside the Docker container using 'Run->Remote Connection...'. If using boot2docker witht eh default configuration

  Host: 192.168.59.103
  Port: 5858

The editor connects and the VM starts to run. One can check this

  $ curl http://192.168.59.103:8080/version

(again assuming boot2docker)

However the breakpoint set in the code is not hit.

As far as I can see this is caused by the mapping from the source path in the Dart Editor and the source path in the container. I have captures the communication between the Dart Editor and the VM in the container, and what caught my eye is the following:

{"id":1,"command":"getStackTrace","params":{"isolateId":383209362}}{ "id": 1, "result": {"callFrames" : [ {"functionName":"main","location": { "url":"file:///app/bin/server.dart","libraryId":13,"tokenOffset":24},"locals":[{"name":"webFiles","value":{"objectId":0,"kind":"object","text":"null"}}]}, ...

and

{"id":2,"command":"setBreakpoint","params":{"isolateId":383209362,"line":9,"url":"file:///usr/local/prj/dart/github/dart_docker/hello/bin/server.dart"}}{"id": 2, "error": "Error: Dart_SetBreakpoint: could not set breakpoint at line 9 in 'file:///usr/local/prj/dart/github/dart_docker/hello/bin/server.dart'"}

(Full capture below)

The file known by the Dart Editor as 'file:///usr/local/prj/dart/github/dart_docker/hello/bin/server.dart' is 'file:///app/bin/server.dart' in the container.

Is there any way of setting up a mapping from the path in the debugger to the path in the debugee?

The demo application google/dart-hello is based on https://registry.hub.docker.com/u/google/dart-runtime/dockerfile/, where the Dart application is installed in /app inside the container with the main entrypoint in /app/bin/server.dart.

Full trace of setting up the debugger connection:

{ "event": "isolate", "params": { "reason": "created", "id": 223000247 }}{ "event": "isolate", "params": { "reason": "created", "id": 383209362 }}{ "event": "paused", "params": { "reason": "breakpoint", "isolateId": 383209362,"location": { "url":"file:///app/bin/server.dart","libraryId":13,"tokenOffset":24}}}{"id":1,"command":"getStackTrace","params":{"isolateId":383209362}}{ "id": 1, "result": {"callFrames" : [ {"functionName":"main","location": { "url":"file:///app/bin/server.dart","libraryId":13,"tokenOffset":24},"locals":[{"name":"webFiles","value":{"objectId":0,"kind":"object","text":"null"}}]},{"functionName":"isolateStartHandler","location": { "url":"dart:isolate-patch/isolate_patch.dart","libraryId":1,"tokenOffset":1126},"locals":[{"name":"ignoreHandler","value":{"objectId":1,"kind":"function","name":"_startIsolate.ignoreHandler","signature":"(dynamic) => dynamic","location": { "url":"dart:isolate-patch/isolate_patch.dart","libraryId":1,"tokenOffset":948}}},{"name":"keepAlivePort","value":{"objectId":2,"kind":"object","classId":54,"text":"object of type _RawReceivePortImpl"}},{"name":"isSpawnUri","value":{"objectId":3,"kind":"boolean","text":"true"}},{"name":"entryPoint","value":{"objectId":4,"kind":"function","name":"main","signature":"() => void","location": { "url":"file:///app/bin/server.dart","libraryId":13,"tokenOffset":14}}},{"name":"message","value":{"objectId":5,"kind":"list","length":3,"text":"[null, [...], null]"}},{"name":"replyTo","value":{"objectId":0,"kind":"object","text":"null"}},{"name":"args","value":{"objectId":6,"kind":"list","length":0,"text":"[]"}},{"name":"isolateMessage","value":{"objectId":0,"kind":"object","text":"null"}}]},{"functionName":"_RawReceivePortImpl@709387912._handleMessage@709387912","location": { "url":"dart:isolate-patch/isolate_patch.dart","libraryId":1,"tokenOffset":608},"classId":54,"locals":[{"name":"handler","value":{"objectId":7,"kind":"function","name":"_startIsolate.isolateStartHandler","signature":"(dynamic) => dynamic","location": { "url":"dart:isolate-patch/isolate_patch.dart","libraryId":1,"tokenOffset":961}}},{"name":"message","value":{"objectId":5,"kind":"list","length":3,"text":"[null, [...], null]"}}]}]}}{"id":2,"command":"setBreakpoint","params":{"isolateId":383209362,"line":9,"url":"file:///usr/local/prj/dart/github/dart_docker/hello/bin/server.dart"}}{"id": 2, "error": "Error: Dart_SetBreakpoint: could not set breakpoint at line 9 in 'file:///usr/local/prj/dart/github/dart_docker/hello/bin/server.dart'"}{"id":3,"command":"getLibraries","params":{"isolateId":383209362}}{ "id": 3, "result": { "libraries": [{"id":0,"url":"dart:core"}, {"id":1,"url":"dart:isolate"}, {"id":2,"url":"dart:mirrors"}, {"id":3,"url":"dart:collection"}, {"id":4,"url":"dart:profiler"}, {"id":5,"url":"dart:nativewrappers"}, {"id":6,"url":"dart:typed_data"}, {"id":7,"url":"dart:async"}, {"id":8,"url":"dart:convert"}, {"id":9,"url":"dart:_internal"}, {"id":10,"url":"dart:math"}, {"id":11,"url":"dart:_builtin"}, {"id":12,"url":"dart:io"}, {"id":13,"url":"file:///app/bin/server.dart"}, {"id":14,"url":"package:http_server/http_server.dart"}, {"id":15,"url":"package:mime/mime.dart"}, {"id":16,"url":"package:path/path.dart"}, {"id":17,"url":"package:mime/src/mime_multipart_transformer.dart"}, {"id":18,"url":"package:mime/src/mime_shared.dart"}, {"id":19,"url":"package:mime/src/mime_type.dart"}, {"id":20,"url":"package:path/src/context.dart"}, {"id":21,"url":"package:path/src/style.dart"}, {"id":22,"url":"package:path/src/path_exception.dart"}, {"id":23,"url":"package:mime/src/bound_multipart_stream.dart"}, {"id":24,"url":"package:mime/src/char_code.dart"}, {"id":25,"url":"package:mime/src/default_extension_map.dart"}, {"id":26,"url":"package:mime/src/magic_number.dart"}, {"id":27,"url":"package:path/src/internal_style.dart"}, {"id":28,"url":"package:path/src/parsed_path.dart"}, {"id":29,"url":"package:path/src/style/posix.dart"}, {"id":30,"url":"package:path/src/style/url.dart"}, {"id":31,"url":"package:path/src/style/windows.dart"}, {"id":32,"url":"package:path/src/characters.dart"}, {"id":33,"url":"package:path/src/utils.dart"}]}}{"id":4,"command":"setLibraryProperties","params":{"libraryId":0,"isolateId":383209362,"debuggingEnabled":"true"}}{"id":5,"command":"setLibraryProperties","params":{"libraryId":1,"isolateId":383209362,"debuggingEnabled":"true"}}{"id":6,"command":"setLibraryProperties","params":{"libraryId":2,"isolateId":383209362,"debuggingEnabled":"true"}}{"id":7,"command":"setLibraryProperties","params":{"libraryId":3,"isolateId":383209362,"debuggingEnabled":"true"}}{"id":8,"command":"setLibraryProperties","params":{"libraryId":4,"isolateId":383209362,"debuggingEnabled":"true"}}{"id":9,"command":"setLibraryProperties","params":{"libraryId":6,"isolateId":383209362,"debuggingEnabled":"true"}}{"id":10,"command":"setLibraryProperties","params":{"libraryId":8,"isolateId":383209362,"debuggingEnabled":"true"}}{"id":11,"command":"setLibraryProperties","params":{"libraryId":10,"isolateId":383209362,"debuggingEnabled":"true"}}{"id":12,"command":"setLibraryProperties","params":{"libraryId":11,"isolateId":383209362,"debuggingEnabled":"true"}}{"id":13,"command":"setLibraryProperties","params":{"libraryId":12,"isolateId":383209362,"debuggingEnabled":"true"}}{"id":14,"command":"setLibraryProperties","params":{"libraryId":13,"isolateId":383209362,"debuggingEnabled":"true"}}{"id":15,"command":"setLibraryProperties","params":{"libraryId":14,"isolateId":383209362,"debuggingEnabled":"true"}}{"id":16,"command":"setLibraryProperties","params":{"libraryId":15,"isolateId":383209362,"debuggingEnabled":"true"}}{"id":17,"command":"setLibraryProperties","params":{"libraryId":16,"isolateId":383209362,"debuggingEnabled":"true"}}{"id":18,"command":"setLibraryProperties","params":{"libraryId":17,"isolateId":383209362,"debuggingEnabled":"true"}}{"id":19,"command":"setLibraryProperties","params":{"libraryId":18,"isolateId":383209362,"debuggingEnabled":"true"}}{"id":20,"command":"setLibraryProperties","params":{"libraryId":19,"isolateId":383209362,"debuggingEnabled":"true"}}{"id":21,"command":"setLibraryProperties","params":{"libraryId":20,"isolateId":383209362,"debuggingEnabled":"true"}}{"id":22,"command":"setLibraryProperties","params":{"libraryId":21,"isolateId":383209362,"debuggingEnabled":"true"}}{"id":23,"command":"setLibraryProperties","params":{"libraryId":22,"isolateId":383209362,"debuggingEnabled":"true"}}{"id":24,"command":"setLibraryProperties","params":{"libraryId":23,"isolateId":383209362,"debuggingEnabled":"true"}}{"id":25,"command":"setLibraryProperties","params":{"libraryId":24,"isolateId":383209362,"debuggingEnabled":"true"}}{"id":26,"command":"setLibraryProperties","params":{"libraryId":25,"isolateId":383209362,"debuggingEnabled":"true"}}{"id":27,"command":"setLibraryProperties","params":{"libraryId":26,"isolateId":383209362,"debuggingEnabled":"true"}}{"id":28,"command":"setLibraryProperties","params":{"libraryId":27,"isolateId":383209362,"debuggingEnabled":"true"}}{"id":29,"command":"setLibraryProperties","params":{"libraryId":28,"isolateId":383209362,"debuggingEnabled":"true"}}{"id":30,"command":"setLibraryProperties","params":{"libraryId":29,"isolateId":383209362,"debuggingEnabled":"true"}}{"id":31,"command":"setLibraryProperties","params":{"libraryId":30,"isolateId":383209362,"debuggingEnabled":"true"}}{"id":32,"command":"setLibraryProperties","params":{"libraryId":31,"isolateId":383209362,"debuggingEnabled":"true"}}{"id":33,"command":"setLibraryProperties","params":{"libraryId":32,"isolateId":383209362,"debuggingEnabled":"true"}}{"id":34,"command":"setLibraryProperties","params":{"libraryId":33,"isolateId":383209362,"debuggingEnabled":"true"}}{"id":35,"command":"setPauseOnException","params":{"exceptions":"unhandled","isolateId":383209362}}{"id":4, 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{"debuggingEnabled": "true"}}{"id":25, "result": {"debuggingEnabled": "true"}}{"id":26, "result": {"debuggingEnabled": "true"}}{"id":27, "result": {"debuggingEnabled": "true"}}{"id":28, "result": {"debuggingEnabled": "true"}}{"id":29, "result": {"debuggingEnabled": "true"}}{"id":30, "result": {"debuggingEnabled": "true"}}{"id":31, "result": {"debuggingEnabled": "true"}}{"id":32, "result": {"debuggingEnabled": "true"}}{"id":33, "result": {"debuggingEnabled": "true"}}{"id":34, "result": {"debuggingEnabled": "true"}}{ "id": 35 }{"id":36,"command":"getLineNumberTable","params":{"libraryId":13,"isolateId":383209362,"url":"file:///app/bin/server.dart"}}{ "id": 36, "result": { "lines": [[1,0,1,1,8,2,20], [2,4,1,5,8,6,17], [4,9,1,10,8,11,46], [6,14,1,15,6,16,10,17,11,18,13], [7,20,3,21,7,22,16,23,18,24,22,25,38,26,39,27,44,28,45], [9,31,3,32,11,33,12,34,13,35,15], [10,37,5,38,15,39,16,40,20,41,21,42,30,43,32,44,36,45,37,46,38,48,42,49,43,50,44,52,50,53,52], [11,55,7,57,13,58,14,60,20,61,21,62,22,64,29,65,31], [12,67,11,68,14,69,15,71,22,72,23,74,26,75,27,77,32,78,35,80,38,81,40], [13,83,13,85,20,86,21,88,29,89,30,91,38,92,39,94,46,95,47,97,50,98,51,100,58,101,59,103,72,104,73,105,74], [14,107,11,108,13,109,18,110,21,111,22,113,29,114,30,116,33,117,34,119,39,120,42,122,52,123,54], [15,125,13,127,20,128,21,130,29,131,30,133,37,134,39,136,51,137,53,139,64,140,65,142,69], [16,144,13,146,20,147,21], [17,150,17,151,19,153,26,154,27,156,42,157,44,159,52,160,53,162,60,163,61,165,62], [18,167,17,168,19,170,26,171,27,173,45,174,47,176,55,177,56,179,66,180,67,182,68], [19,184,17,185,19,187,26,188,27], [20,191,27,193,28,194,30,196,38,197,39,199,58,200,59,202,60], [21,204,17,205,19,207,24,208,25,209,26], [22,211,11,212,13,213,18], [23,215,13,216,21,217,22,219,34,220,35,222,42,223,43], [24,225,11], [25,227,7,228,8,229,9], [26,231,5,232,6,233,7], [27,235,3,236,4], [28,238,3,240,10,241,12,242,13,244,14,245,16,247,26,248,28], [29,250,5,252,10,253,11,255,37,257,39,259,41,261,52,263,53,264,54], [30,266,3,267,4,268,5], [31,270,1]]}}{"id":37,"command":"resume","params":{"isolateId":383209362}}{ "id": 37 }