VS Code extension not starting

Perhaps I’m missing something here, but the VS Code extension appears to not work at all?

I have cfn-lint installed and I can use the CLI as expected -

dgard@THH-TPI6674:~$ cfn-lint --version
cfn-lint 0.51.0

Initially when I start VS Code there is no output for the extension, but after I try to run the ‘Preview CloudFormation as a graph’ command I see the following output for ‘CloudFormation linter Language Server’ -

Settings have been updated...
Settings: {"cfnLint":{"enableAutocomplete":true,"validateUsingJsonSchema":false,"path":"cfn-lint","appendRules":[],"ignoreRules":[],"overrideSpecPath":""}}

It should be noted that 'Preview CloudFormation as a graph ’ doesn’t work either though -

Command ‘Preview CloudFormation template as graph’ resulted in an error (command ‘extension.sidePreview’ not found)

The only requirements for the extension say that cfn-lint and (optionally) pydot need to be installed, and both are available.

Any tips on how to get this working, as it seems like it might be useful.

Thanks, David

[JadenSimon]

The AWS Toolkit does have different language servers for YAML files, but none are called ‘CloudFormation YAML’ so I’m not sure where that is coming from. Is this showing up as a Language Mode?

[dgard1981]

I think I’ve found the issue. I just created a template, but I forgot to put .cfn in the name, and cfn-lint picked up an error. When I renamed the file, the language mode automatically changed to ‘CloudFormation YAML’ (from the AWS Toolkit extension) as opposed to just ‘YAML’, and cfn-lint stopped working again.

So it seems that this is two extensions not playing well together.