How to enable logs for Language server in Visual Studio Code

Question

In the Language Server Extension Guide it says:

'If you are using vscode-languageclient to implement the client, you can specify a setting [langId].trace.server that instructs the Client to log communications between Language Client / Server to a channel of the Language Client's name.

For lsp-sample, you can set this setting: "languageServerExample.trace.server": "verbose". Now head to the channel "Language Server Example". You should see the logs:

Where and how exactly do I specify this setting in VS Code?

score 5 · Answer 1 · answered Mar 20 '22 at 16:43

Found it!

You need to create a new Node.js Attach run configuration in your launch.json.

{
    "name": "Attach",
    "port": 6009,
    "request": "attach",
    "skipFiles": [
        "<node_internals>/**"
    ],
    "type": "pwa-node"
},

And change the port from default 9229 to 6009. You also need to pass this 6009 port in the ServerOptions when instantiating new LanguageClient():

After that, when you start your plugin with F5, you can now go to the Run view and run the newly created "Attach" configuration alongside your client process:

When both processes are running, you can switch between them in the Call Stack section to see either your client console.logs or your language server's:

_{_{Just after posting a bounty, of course, like always...}}

amirali · Accepted Answer · 2018-10-17T15:33:19.007

What I do for php language server is adding "log": true to launch.json file, Then the compiler will try to show logs when you press f5 to start debugging. But from what I understand from the documentation you have shared in your question, You can follow this instructions (I don't guarantee this will work, As I mentioned this is the instruction for what you have shared in your question):

Press Ctrl+comma.
Search for "trace server".
Now languages should be listed. If you are on the latest version of vscode, choose verbose in any language server you want.
If you are on an older version of vscode, then choose the pencil button next to the language you want, and select "verbose".

Thank you very much for your help. Do you know how I can view the output of console.log() statements executed within the server? They do not seem to display in the output. — Itachinome, Sep 22 '18 at 13:35

score 0 · Answer 3 · answered Dec 12 '20 at 08:52

0

You can also change the default value in your package.json:

"languageServerExample.trace.server": {
                    "scope": "window",
                    "type": "string",
                    "enum": ["off","messages","verbose"],
                    "default": "verbose",

answered Dec 12 '20 at 08:52

Wolfgang Geck

1

2

Is that the package.json for the client folder only or package.json at the root folder (lsp-sample) – Rob Hinchliff Jan 03 '23 at 15:30

sinoTrinity · Answer 4 · 2019-11-06T10:15:55.183

-1

Change that in the workspace setting of the newly opened VS Code instance titled [Extension Development Host], not the original VS Code.

edited Nov 06 '19 at 10:15

answered Nov 06 '19 at 09:21

sinoTrinity

1,125
2
15
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It would be great if you could extend your answer with more specific information like: change this in the file named "blah.txt" ... Otherwise your answer will just help a reduced number of people – Alejandro González Oct 14 '21 at 12:50

How to enable logs for Language server in Visual Studio Code

4 Answers4