Error connecting to the service protocol: failed to connect.

[wilsonowilson]

I've seen this error a lot lately. Whenever I try to attach Vscode to my Nativeshell app, this error is returned:

Error connecting to the service protocol: failed to connect to http://127.0.0.1:49925/wGGO2vRhFfw=/.

Running a normal Flutter app works fine. Cleaning flutter and restarting my computer has no effect. It seems to randomly start and stop working.

[knopp]

is the URL same as the URL printed when you run the app (cargo run)?

[wilsonowilson]

Oh it's not the same. The port is different

[knopp]

Which flutter version are you using? There was a regression recently in flutter tool debug attach caused by NNBD migration, but that should be resolved in latest master.

[wilsonowilson]

I'm on Flutter 2.6.0-1.0.pre.108 from 2 days ago.

[wilsonowilson]

I've also noticed that the last three digits of the port change randomly every time I try to attach vscode.

The vmservice file contains the exact same url that Nativeshell writes, but for some reason, flutter uses a different one.

[wilsonowilson]

I should also mention that this behavior isn't specific to my project. All nativeshell apps, including the example project, don't work. Normal flutter apps do.

[knopp]

So flutter is trying to attach to different port than the vmservice file? That looks like a bug in flutter tool. I'll see if I can reproduce this.

[knopp]

Can you try the following?

In one terminal

cargo run

In second

flutter attach -v -d macos --debug-url <http url printed during cargo run>

and post here the logs from flutter attach?

[wilsonowilson]

Here are the logs

[ +135 ms] executing: sysctl hw.optional.arm64
[  +34 ms] Exit code 0 from: sysctl hw.optional.arm64
[   +3 ms] hw.optional.arm64: 1
[   +9 ms] executing: [/Users/wilson/Developer/SDK/flutter/] git -c log.showSignature=false log -n 1 --pretty=format:%H
[  +29 ms] Exit code 0 from: git -c log.showSignature=false log -n 1 --pretty=format:%H
[        ] 334c95dbd919db697d849acad71a1d101d515181
[   +1 ms] executing: [/Users/wilson/Developer/SDK/flutter/] git tag --points-at 334c95dbd919db697d849acad71a1d101d515181
[  +68 ms] Exit code 0 from: git tag --points-at 334c95dbd919db697d849acad71a1d101d515181
[   +2 ms] executing: [/Users/wilson/Developer/SDK/flutter/] git describe --match *.*.* --long --tags 334c95dbd919db697d849acad71a1d101d515181
[  +53 ms] Exit code 0 from: git describe --match *.*.* --long --tags 334c95dbd919db697d849acad71a1d101d515181
[        ] 2.6.0-0.0.pre-161-g334c95dbd9
[  +12 ms] executing: [/Users/wilson/Developer/SDK/flutter/] git rev-parse --abbrev-ref --symbolic @{u}
[  +17 ms] Exit code 0 from: git rev-parse --abbrev-ref --symbolic @{u}
[        ] origin/master
[        ] executing: [/Users/wilson/Developer/SDK/flutter/] git ls-remote --get-url origin
[  +15 ms] Exit code 0 from: git ls-remote --get-url origin
[        ] https://github.com/flutter/flutter.git
[ +139 ms] Unable to locate an Android SDK.
[  +11 ms] executing: [/Users/wilson/Developer/SDK/flutter/] git rev-parse --abbrev-ref HEAD
[  +24 ms] Exit code 0 from: git rev-parse --abbrev-ref HEAD
[        ] master
[  +10 ms] executing: sw_vers -productName
[  +23 ms] Exit code 0 from: sw_vers -productName
[        ] macOS
[        ] executing: sw_vers -productVersion
[  +17 ms] Exit code 0 from: sw_vers -productVersion
[        ] 12.0
[        ] executing: sw_vers -buildVersion
[  +18 ms] Exit code 0 from: sw_vers -buildVersion
[        ] 21A5304g
[  +78 ms] Artifact Instance of 'AndroidGenSnapshotArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'AndroidInternalBuildArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'IOSEngineArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'FlutterWebSdk' is not required, skipping update.
[   +3 ms] Artifact Instance of 'WindowsEngineArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'WindowsUwpEngineArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'MacOSEngineArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'LinuxEngineArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'LinuxFuchsiaSDKArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'MacOSFuchsiaSDKArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'FlutterRunnerSDKArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'FlutterRunnerDebugSymbols' is not required, skipping update.
[  +50 ms] Artifact Instance of 'MaterialFonts' is not required, skipping update.
[        ] Artifact Instance of 'GradleWrapper' is not required, skipping update.
[        ] Artifact Instance of 'AndroidGenSnapshotArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'AndroidInternalBuildArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'IOSEngineArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'FlutterWebSdk' is not required, skipping update.
[        ] Artifact Instance of 'FlutterSdk' is not required, skipping update.
[        ] Artifact Instance of 'WindowsEngineArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'WindowsUwpEngineArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'MacOSEngineArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'LinuxEngineArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'LinuxFuchsiaSDKArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'MacOSFuchsiaSDKArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'FlutterRunnerSDKArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'FlutterRunnerDebugSymbols' is not required, skipping update.
[        ] Artifact Instance of 'IosUsbArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'IosUsbArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'IosUsbArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'IosUsbArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'IosUsbArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'FontSubsetArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'PubDependencies' is not required, skipping update.
[  +21 ms] executing: sysctl hw.optional.arm64
[  +10 ms] Exit code 0 from: sysctl hw.optional.arm64
[        ] hw.optional.arm64: 1
[        ] executing: /usr/bin/arch -arm64e xcrun xcodebuild -version
[ +125 ms] Exit code 0 from: /usr/bin/arch -arm64e xcrun xcodebuild -version
[        ] Xcode 13.0
           Build version 13A5154h
[   +1 ms] objc[59042]: Class AMSupportURLConnectionDelegate is implemented in both /usr/lib/libauthinstall.dylib (0x201ec5460) and
/Library/Apple/System/Library/PrivateFrameworks/MobileDevice.framework/Versions/A/MobileDevice (0x10a4942c8). One of the two will be used. Which
one is undefined.
           objc[59042]: Class AMSupportURLSession is implemented in both /usr/lib/libauthinstall.dylib (0x201ec54b0) and
           /Library/Apple/System/Library/PrivateFrameworks/MobileDevice.framework/Versions/A/MobileDevice (0x10a494318). One of the two will be
           used. Which one is undefined.
[ +187 ms] Connecting to service protocol: http://127.0.0.1:62619/wwFZgAUGELw=/
[ +231 ms] Launching a Dart Developer Service (DDS) instance at http://127.0.0.1:0, connecting to VM service at
http://127.0.0.1:62619/wwFZgAUGELw=/.
[ +178 ms] DDS is listening at http://127.0.0.1:62662/7BApDUaiM3E=/.
[  +95 ms] Successfully connected to service protocol: http://127.0.0.1:62619/wwFZgAUGELw=/
[  +36 ms] DevFS: Creating new filesystem on the device (null)
[  +26 ms] DevFS: Created new filesystem on the device (file:///var/folders/nr/h5fpm1zn3y98b4skkg8l46gw0000gn/T/velicour2tZ5PF/velicour/)
[   +2 ms] Updating assets
[ +172 ms] Syncing files to device macOS...
[   +2 ms] <- reset
[        ] Compiling dart to kernel with 0 updated files
[   +9 ms] /Users/wilson/Developer/SDK/flutter/bin/cache/dart-sdk/bin/dart --disable-dart-dev
/Users/wilson/Developer/SDK/flutter/bin/cache/artifacts/engine/darwin-x64/frontend_server.dart.snapshot --sdk-root
/Users/wilson/Developer/SDK/flutter/bin/cache/artifacts/engine/common/flutter_patched_sdk/ --incremental --target=flutter
--debugger-module-names --experimental-emit-debug-metadata --output-dill
/var/folders/nr/h5fpm1zn3y98b4skkg8l46gw0000gn/T/flutter_tools.CYkV6Y/flutter_tool.i3EO9b/app.dill --packages
/Users/wilson/Developer/Projects/velicour/.dart_tool/package_config.json -Ddart.vm.profile=false -Ddart.vm.product=false --enable-asserts
--track-widget-creation --filesystem-scheme org-dartlang-root --initialize-from-dill build/cache.dill.track.dill --flutter-widget-cache
--enable-experiment=alternative-invalidation-strategy
[  +28 ms] <- compile package:velicour/main.dart
[+1489 ms] Activating Dart DevTools...
[+3261 ms] Activating Dart DevTools... (completed in 3.2s)
[+3397 ms] Updating files.
[   +1 ms] DevFS: Sync finished
[   +2 ms] Syncing files to device macOS... (completed in 8.2s)
[   +4 ms] Synced 0.0MB.
[   +3 ms] <- accept
[   +3 ms] Connected to _flutterView/0x7ff3ad877e20.
[  +24 ms] Flutter run key commands.
[   +3 ms] r Hot reload. 🔥🔥🔥
[   +9 ms] R Hot restart.
[        ] h List all available interactive commands.
[   +2 ms] d Detach (terminate "flutter run" but leave application running).
[        ] c Clear the screen
[        ] q Quit (terminate the application on the device).
[        ] 💪 Running with sound null safety 💪
[   +2 ms] An Observatory debugger and profiler on macOS is available at: http://127.0.0.1:62662/7BApDUaiM3E=/
[   +3 ms] The Flutter DevTools debugger and profiler on macOS is available at: http://127.0.0.1:9101?uri=http://127.0.0.1:62662/7BApDUaiM3E=/

It suddenly started working again after doing nothing for a few hours. But the problem usually reoccurs after a while. I'll post the logs once I face it again.

[wilsonowilson]

Just started facing this issue again. The logs are pretty synonymous with the previous logs.

flutter attach -v -d macos --debug-url http://127.0.0.1:50445/8Yi_Kjwp5QU=/

[ +136 ms] executing: sysctl hw.optional.arm64
[  +32 ms] Exit code 0 from: sysctl hw.optional.arm64
[   +3 ms] hw.optional.arm64: 1
[   +9 ms] executing: [/Users/wilson/Developer/SDK/flutter/] git -c log.showSignature=false log -n 1 --pretty=format:%H
[  +39 ms] Exit code 0 from: git -c log.showSignature=false log -n 1 --pretty=format:%H
[        ] 334c95dbd919db697d849acad71a1d101d515181
[   +1 ms] executing: [/Users/wilson/Developer/SDK/flutter/] git tag --points-at 334c95dbd919db697d849acad71a1d101d515181
[  +83 ms] Exit code 0 from: git tag --points-at 334c95dbd919db697d849acad71a1d101d515181
[   +2 ms] executing: [/Users/wilson/Developer/SDK/flutter/] git describe --match *.*.* --long --tags 334c95dbd919db697d849acad71a1d101d515181
[  +50 ms] Exit code 0 from: git describe --match *.*.* --long --tags 334c95dbd919db697d849acad71a1d101d515181
[        ] 2.6.0-0.0.pre-161-g334c95dbd9
[  +12 ms] executing: [/Users/wilson/Developer/SDK/flutter/] git rev-parse --abbrev-ref --symbolic @{u}
[  +17 ms] Exit code 0 from: git rev-parse --abbrev-ref --symbolic @{u}
[        ] origin/master
[        ] executing: [/Users/wilson/Developer/SDK/flutter/] git ls-remote --get-url origin
[  +18 ms] Exit code 0 from: git ls-remote --get-url origin
[        ] https://github.com/flutter/flutter.git
[ +153 ms] Unable to locate an Android SDK.
[  +10 ms] executing: [/Users/wilson/Developer/SDK/flutter/] git rev-parse --abbrev-ref HEAD
[  +21 ms] Exit code 0 from: git rev-parse --abbrev-ref HEAD
[   +1 ms] master
[   +8 ms] executing: sw_vers -productName
[  +29 ms] Exit code 0 from: sw_vers -productName
[        ] macOS
[        ] executing: sw_vers -productVersion
[  +22 ms] Exit code 0 from: sw_vers -productVersion
[        ] 12.0
[        ] executing: sw_vers -buildVersion
[  +23 ms] Exit code 0 from: sw_vers -buildVersion
[        ] 21A5304g
[  +65 ms] Artifact Instance of 'AndroidGenSnapshotArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'AndroidInternalBuildArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'IOSEngineArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'FlutterWebSdk' is not required, skipping update.
[   +3 ms] Artifact Instance of 'WindowsEngineArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'WindowsUwpEngineArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'MacOSEngineArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'LinuxEngineArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'LinuxFuchsiaSDKArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'MacOSFuchsiaSDKArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'FlutterRunnerSDKArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'FlutterRunnerDebugSymbols' is not required, skipping update.
[  +48 ms] Artifact Instance of 'MaterialFonts' is not required, skipping update.
[        ] Artifact Instance of 'GradleWrapper' is not required, skipping update.
[        ] Artifact Instance of 'AndroidGenSnapshotArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'AndroidInternalBuildArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'IOSEngineArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'FlutterWebSdk' is not required, skipping update.
[        ] Artifact Instance of 'FlutterSdk' is not required, skipping update.
[        ] Artifact Instance of 'WindowsEngineArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'WindowsUwpEngineArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'MacOSEngineArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'LinuxEngineArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'LinuxFuchsiaSDKArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'MacOSFuchsiaSDKArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'FlutterRunnerSDKArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'FlutterRunnerDebugSymbols' is not required, skipping update.
[        ] Artifact Instance of 'IosUsbArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'IosUsbArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'IosUsbArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'IosUsbArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'IosUsbArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'FontSubsetArtifacts' is not required, skipping update.
[        ] Artifact Instance of 'PubDependencies' is not required, skipping update.
[  +20 ms] executing: sysctl hw.optional.arm64
[  +12 ms] Exit code 0 from: sysctl hw.optional.arm64
[        ] hw.optional.arm64: 1
[        ] executing: /usr/bin/arch -arm64e xcrun xcodebuild -version
[ +127 ms] Exit code 0 from: /usr/bin/arch -arm64e xcrun xcodebuild -version
[        ] Xcode 13.0
           Build version 13A5154h
[   +1 ms] objc[24804]: Class AMSupportURLConnectionDelegate is implemented in both /usr/lib/libauthinstall.dylib (0x215fa9460) and
/Library/Apple/System/Library/PrivateFrameworks/MobileDevice.framework/Versions/A/MobileDevice (0x106f942c8). One of the two will be used.
Which one is undefined.
           objc[24804]: Class AMSupportURLSession is implemented in both /usr/lib/libauthinstall.dylib (0x215fa94b0) and
           /Library/Apple/System/Library/PrivateFrameworks/MobileDevice.framework/Versions/A/MobileDevice (0x106f94318). One of the two will
           be used. Which one is undefined.
[ +182 ms] Connecting to service protocol: http://127.0.0.1:50445/8Yi_Kjwp5QU=/
[ +255 ms] Launching a Dart Developer Service (DDS) instance at http://127.0.0.1:0, connecting to VM service at
http://127.0.0.1:50445/8Yi_Kjwp5QU=/.
[ +139 ms] DDS is listening at http://127.0.0.1:50468/7EpInU_Pc7Q=/.
[  +76 ms] Successfully connected to service protocol: http://127.0.0.1:50445/8Yi_Kjwp5QU=/
[  +48 ms] DevFS: Creating new filesystem on the device (null)
[  +22 ms] DevFS: Created new filesystem on the device (file:///var/folders/nr/h5fpm1zn3y98b4skkg8l46gw0000gn/T/velicourv8LILc/velicour/)
[   +2 ms] Updating assets
[ +187 ms] Syncing files to device macOS...
[   +2 ms] <- reset
[        ] Compiling dart to kernel with 0 updated files
[   +9 ms] /Users/wilson/Developer/SDK/flutter/bin/cache/dart-sdk/bin/dart --disable-dart-dev
/Users/wilson/Developer/SDK/flutter/bin/cache/artifacts/engine/darwin-x64/frontend_server.dart.snapshot --sdk-root
/Users/wilson/Developer/SDK/flutter/bin/cache/artifacts/engine/common/flutter_patched_sdk/ --incremental --target=flutter
--debugger-module-names --experimental-emit-debug-metadata --output-dill
/var/folders/nr/h5fpm1zn3y98b4skkg8l46gw0000gn/T/flutter_tools.l6nQ12/flutter_tool.AeCypx/app.dill --packages
/Users/wilson/Developer/Projects/velicour/.dart_tool/package_config.json -Ddart.vm.profile=false -Ddart.vm.product=false --enable-asserts
--track-widget-creation --filesystem-scheme org-dartlang-root --initialize-from-dill build/cache.dill.track.dill --flutter-widget-cache
--enable-experiment=alternative-invalidation-strategy
[  +45 ms] <- compile package:velicour/main.dart
[+1615 ms] Activating Dart DevTools...
[+3343 ms] Activating Dart DevTools... (completed in 3.3s)
[+2920 ms] Updating files.
[   +7 ms] DevFS: Sync finished
[   +3 ms] Syncing files to device macOS... (completed in 7.9s)
[   +2 ms] Synced 0.0MB.
[   +4 ms] <- accept
[  +25 ms] Connected to _flutterView/0x7fe607100a20.
[  +18 ms] Flutter run key commands.
[  +13 ms] r Hot reload. 🔥🔥🔥
[   +3 ms] R Hot restart.
[        ] h List all available interactive commands.
[        ] d Detach (terminate "flutter run" but leave application running).
[        ] c Clear the screen
[   +4 ms] q Quit (terminate the application on the device).
[        ] 💪 Running with sound null safety 💪
[   +1 ms] An Observatory debugger and profiler on macOS is available at: http://127.0.0.1:50468/7EpInU_Pc7Q=/
[   +5 ms] The Flutter DevTools debugger and profiler on macOS is available at: http://127.0.0.1:9100?uri=http://127.0.0.1:50468/7EpInU_Pc7Q=/

[knopp]

The logs looks good. You can capture logs from dart-code as well (Dart: Capture Debugging Logs in vscode) - do they show anything different?

[wilsonowilson]

Before "connecting to service protocol", it shows this:

[ +199 ms] Attempting to forward device port 50445 to host port 50695
[   +1 ms] executing: /Users/wilson/Developer/SDK/flutter/bin/cache/artifacts/usbmuxd/iproxy 50695:50445 --udid 00008020-001934582144002E --debug
[+1028 ms] Forwarded port ForwardedPort HOST:50695 to DEVICE:50445

The original port shown in the url is 50445, but Dart code is forwarding 50695 to it

[knopp]

iproxy shouldn't be involved. That's when you're debugging on a device. Is the selected device in vscode (status bar option) macOS?

[wilsonowilson]

Ah, that was the problem. The device changed automatically when I plugged in a new one. Setting it back to macOS fixed it. Thanks for the help!

[knopp]

It should be possible to set deviceId in launch.json. You can try adding "deviceId": "macos", for osx to see if it helps. It should override the setting.

[wilsonowilson]

Overriding the deviceId works great. Thanks!

[knopp]

I think I should update the template launch.json :)