vscode-go/README.md

Go for Visual Studio Code

This extension adds rich language support for the Go language to VS Code.

Read the Changelog to know what has changed over the last few versions of this extension.

Table of Contents

• Language Features
  • IntelliSense
  • Code Navigation
  • Code Editing
  • Diagnostics
  • Testing
  • Debugging
  • Others
• How to use this extension?
  • Go Language Server
    • Settings to control the use of the Go language server
    • Provide feedback on gopls
  • Linter
  • Commands
  • Optional: Debugging
    • Remote Debugging
• Install or update all dependencies
• Building and Debugging the Extension
• Tools this extension depends on
• Frequently Asked Questions (FAQ)
• Contributing
• Code of Conduct
• License

Language Features

IntelliSense

• Auto Completion of symbols as you type (using gocode)
• Signature Help for functions as you type (using gogetdoc or godef+go doc)
• Quick Info on the symbol as you hover over it (using gogetdoc or godef+go doc)

Code Navigation

• Go to or Peek Definition of symbols (using gogetdoc or godef+go doc)
• Find References of symbols and Implementations of interfaces (using guru)
• Go to symbol in file or see the file outline (using go-outline)
• Go to symbol in workspace (using go-symbols)
• Toggle between a Go program and the corresponding test file.

Code Editing

• Code Snippets for quick coding
• Format code on file save as well as format manually (using goreturns or goimports which also remove unused imports or gofmt). To disable the format on save feature, add "[go]": {"editor.formatOnSave": false} to your settings.
• Symbol Rename (using gorename. Note: For Undo after rename to work in Windows you need to have diff tool in your path)
• Add Imports to current file (using gopkgs)
• Add/Remove Tags on struct fields (using gomodifytags)
• Generate method stubs for interfaces (using impl)
• Fill struct literals with default values (using fillstruct)

Diagnostics

• Build-on-save to compile code and show build errors. (using go build and go test)
• Vet-on-save to run go vet and show errors as warnings
• Lint-on-save to show linting errors as warnings (using golint, gometalinter, staticcheck, golangci-lint or revive)
• Semantic/Syntactic error reporting as you type (using gotype-live)

Testing

• Run Tests under the cursor, in current file, in current package, in the whole workspace using either commands or codelens
• Run Benchmarks under the cursor using either commands or codelens
• Show code coverage either on demand or after running tests in the package.
• Generate unit tests skeleton (using gotests)

Debugging

• Debug your code, binaries or tests (using delve)

Others

• Install/Update all dependent Go tools
• Upload to the Go Playground (using goplay)

How to use this extension?

Install and open Visual Studio Code. Press Ctrl+Shift+X or Cmd+Shift+X to open the Extensions pane. Find and install the Go extension. You can also install the extension from the Marketplace. Open any .go file in VS Code. The extension is now activated.

This extension uses a set of Go tools to provide the various rich features. These tools are installed in your GOPATH by default. If you wish to have these tools in a separate location, provide the desired location in the setting go.toolsGopath. Read more about this and the tools at Go tools that the Go extension depends on.

You will see Analysis Tools Missing in the bottom right, clicking this will offer to install all of the dependent Go tools. You can also run the command Go: Install/Update tools to install/update the same.

Note 1: Read GOPATH in the VS Code Go extension to learn about the different ways you can get the extension to set GOPATH.

Note 2: The Format on save feature has a timeout of 750ms after which the formatting is aborted. You can change this timeout using the setting editor.formatOnSaveTimeout. This feature gets disabled when you have enabled the Auto Save feature in Visual Studio Code.

Note 3: This extension uses gocode to provide completion lists as you type. If you have disabled the go.buildOnSave setting, then you may not get fresh results from not-yet-built dependencies. Therefore, ensure you have built your dependencies manually in such cases.

Customizing the Go extension features

The Go extension is ready to use on the get go. If you want to customize the features, you can edit the settings in your User or Workspace settings. Read All Settings & Commands in Visual Studio Code Go extension for the full list of options and their descriptions.

Go Language Server

The Go extension uses a host of Go tools to provide the various language features. An alternative is to use a single language server that provides the same features using the Language Server Protocol

Previously, we added support to use go-langserver, the language server from Sourcegraph. There is no active development for it anymore and it doesn't support Go modules. Therefore, we are now switching to use gopls, the language server from Google which is currently in active development.

• If you are already using the language server from Sourcegraph, you can continue to use it as long as you are not using Go modules. We do suggest you to move to using gopls though.
  • To do so, delete the go-langserver binary/executable in your machine and this extension will prompt you to install gopls after a reload of the VS Code window.
• Since the language server from Google provides much better support for Go modules, you will be prompted about it when the extension detects that you are working on a project that uses Go modules.
• If you have never used language server before, and now opt to use it, you will be prompted to install and use the language server from Google as long as you are using a Go version > 1.10

Note: The language server from Google supports Go version > 1.10 only

Settings to control the use of the Go language server

Below are the settings you can use to control the use of the language server. You need to reload the VS Code window for any changes in these settings to take effect.

• Set go.useLanguageServer to true to enable the use of language server
• Use the setting go.languageServerExperimentalFeatures to control which features do you want to be powered by the language server. Below are the various features you can control. By default, all are set to true.

  "go.languageServerExperimentalFeatures": {
    "format": true,
    "autoComplete": true,
    "rename": true,
    "goToDefinition": true,
    "hover": true,
    "signatureHelp": true,
    "goToTypeDefinition": true,
    "goToImplementation": true,
    "documentSymbols": true,
    "workspaceSymbols": true,
    "findReferences": true,
    "diagnostics": true,
    "documentLink": true
  }

• Set "go.languageServerFlags": ["-logfile", "path to a text file that exists"] to collect logs in a log file.
• Set "go.languageServerFlags": ["-rpc.trace"] to see the complete rpc trace in the output panel (View -> Output -> gopls)

Setting to change the language server being used

If you want to try out other language servers, for example, bingo, then install it and add the below setting

"go.alternateTools": {
  "gopls": "bingo"
}

This will tell the Go extension to use bingo in place of gopls.

Provide feedback on gopls

If you find any problems using the gopls language server, please first check the list of existing issues for gopls and update the relevant ones with your case before logging a new one at https://github.com/golang/go/issues

Helpful links for gopls

• Wiki for gopls
• Recommended settings for VSCode when using gopls
• Troubleshooting for gopls
• Known bugs with gopls
• Github issues for gopls

Linter

A linter is a tool giving coding style feedback and suggestions. By default this extension uses the official golint as a linter.

You can change the default linter and use the more advanced golangci-lint by setting go.lintTool to "golangci-lint" in your settings. It shares some of the performance characteristics of megacheck, but supports a broader range of tools. You can configure golangci-lint with go.lintFlags, for example to show issues only in new code and to enable all linters:

  "go.lintFlags": ["--enable-all", "--new"],

You can also use staticcheck.

Another alternative of golint is revive. It is extensible, configurable, provides superset of the rules of golint, and has significantly better performance.

To configure revive, use:

  "go.lintFlags": ["-exclude=vendor/...", "-config=${workspaceFolder}/config.toml"]

Finally, the result of those linters will show right in the code (locations with suggestions will be underlined), as well as in the output pane.

Commands

In addition to integrated editing features, the extension also provides several commands in the Command Palette for working with Go files:

• Go: Add Import to add an import from the list of packages in your Go context
• Go: Current GOPATH to see your currently configured GOPATH
• Go: Test at cursor to run a test at the current cursor position in the active document
• Go: Test Package to run all tests in the package containing the active document
• Go: Test File to run all tests in the current active document
• Go: Test Previous to run the previously run test command
• Go: Test All Packages in Workspace to run all tests in the current workspace
• Go: Generate Unit Tests For Package Generates unit tests for the current package
• Go: Generate Unit Tests For File Generates unit tests for the current file
• Go: Generate Unit Tests For Function Generates unit tests for the selected function in the current file
• Go: Install Tools Installs/updates all the Go tools that the extension depends on
• Go: Add Tags Adds configured tags to selected struct fields.
• Go: Remove Tags Removes configured tags from selected struct fields.
• Go: Generate Interface Stubs Generates method stubs for given interface
• Go: Fill Struct Fills struct literal with default values
• Go: Run on Go Playground Upload the current selection or file to the Go Playground

You can access all of the above commands from the command palette (Cmd+Shift+P or Ctrl+Shift+P).

A few of these are available in the editor context menu as an experimental feature as well. To control which of these commands show up in the editor context menu, update the setting go.editorContextMenuCommands.

Optional: Debugging

To use the debugger, you must currently manually install delve. See the Installation Instructions for full details. On MacOS it requires creating a self-signed cert to sign the dlv binary.

For more read Debugging Go Code Using VS Code.

Remote Debugging

To remote debug using VS Code, read Remote Debugging.

Install or update all dependencies

To quickly get all dependencies installed (or updated) see the Go Tools wiki page.

Building and Debugging the Extension

You can set up a development environment for debugging the extension during extension development. Read more at Building, Debugging and Sideloading the extension in Visual Studio Code.

Tools this extension depends on

This extension uses a host of Go tools to provide the various rich features. These tools are installed in your GOPATH by default. If you wish to have the extension use a separate GOPATH for its tools, provide the desired location in the setting go.toolsGopath. Read more about this and the tools at Go tools that the Go extension depends on.

Frequently Asked Questions (FAQ)

Please see our wiki on Frequently Asked Questions to get answers to your questions or get started with troubleshooting.

Contributing

This project welcomes contributions and suggestions. Please go through our Contributing Guide to learn how you can contribute. It also includes details on the Contributor License Agreement.

Code of Conduct

This project has adopted the Microsoft Open Source Code of Conduct. For more information see the Code of Conduct FAQ or contact opencode@microsoft.com with any additional questions or comments.

License

MIT