Getting error on initalizing webviz

[cjds]

I tried to build webviz using npm run build and npm run docs but I get

Error initializing player
Error: Expected 1 top level type definition for 'Header' but found 0
    at findTypeByName (https://webviz.io/dist/WorkerDataProvider.worker.js?0441abdf8c8d84b2f526:122:2477)
    at https://webviz.io/dist/WorkerDataProvider.worker.js?0441abdf8c8d84b2f526:122:3089
    at Array.forEach (<anonymous>)
    at https://webviz.io/dist/WorkerDataProvider.worker.js?0441abdf8c8d84b2f526:122:3027
    at Array.forEach (<anonymous>)
    at parseMessageDefinition (https://webviz.io/dist/WorkerDataProvider.worker.js?0441abdf8c8d84b2f526:122:2977)
    at https://webviz.io/dist/WorkerDataProvider.worker.js?0441abdf8c8d84b2f526:527:333
    at Array.forEach (<anonymous>)
    at exports.bagConnectionsToDatatypes (https://webviz.io/dist/WorkerDataProvider.worker.js?0441abdf8c8d84b2f526:527:278)
    at exports.default.initialize (https://webviz.io/dist/WorkerDataProvider.worker.js?0441abdf8c8d84b2f526:407:3325)

when I drag and drop a bag into the UI

[cjds]

Commit I'm trying out is e9835e5

[janpaul123]

Looks like an issue with the bag. How was it recorded? Any chance you can share it with us?

[cjds]

I'll check but it might have been through a simulator. I will sanitize the bag of private information and attach it

[cjds]

https://drive.google.com/file/d/1aapnmnWaEPQ0piEowbSGMsoDNmzXVpio/view?usp=sharing

Attached is the bag file

[janpaul123]

What version of ROS are you on? The message definitions looks pretty old and malformed. First it uses the old Header definition instead of std_msgs/Header, but that's allowed per the bag format. But also there is a topic which uses DiagnosticStatus in the message definition, but the definition for DiagnosticStatus itself is not present in that header. That looks malformed per the description here: "message_definition: full text of message definition (output of gendeps --cat)".

[cjds]

Sorry, I don't think I follow your comment (not super well versed with the rosbag format).

1. We're using Melodic
2. To generate the DiagnosticStatus messages we're using https://github.com/ros/diagnostics which hasn't been changed since Indigo but does have a melodic release (maybe a PR to that is needed). (Assuming you are talking about the /diagnostics_toplevel_state topic)
3. Could you point me to the topic using the old school Header message because I wasn't able to find it using old school rosbag info?

Thanks

[janpaul123]

Huh, weird. To clarify: the problem seems to be that the bag does not properly contain the message definitions inside. How did you generate the bag? Did you just use rosbag record or something else?

[janpaul123]

I suspect that there's something weird with how the bag was generated, because when I run rosbag fix 2019-12-06-05-44-04.088091_task-3715_action-57980_freight100-1274_0.bag out.bag --force then it produces a bag that I can play with Webviz just fine.

[cjds]

I think that may be it...

We use the rosbag C++ API directly.

https://github.com/ros/ros_comm/tree/melodic-devel/tools/rosbag

Specifically https://github.com/ros/ros_comm/blob/melodic-devel/tools/rosbag_storage/include/rosbag/bag.h#L165 that line is what it comes down to.

I think I'll check the changes that fix is doing and either make an upstream change to rosbag or change our downstream use of it. Thanks for the help.