vscode-go/README.md

Go for Visual Studio Code

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

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

Language Features

IntelliSense

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

Code Navigation

• Go to or Peek Definition of symbols (using gogetdoc or godef+godoc)
• 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 or gofmt)
• 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, megacheck, 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 (Experimental)

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 feature.

Set go.useLanguageServer to true to use the Go language server from Sourcegraph for features like Hover, Definition, Find All References, Signature Help, Go to Symbol in File and Workspace.

• This is an experimental feature and is not available in Windows yet.
• Since only a single language server is spun up for given VS Code instance, having multi-root setup where the folders have different GOPATH is not supported.
• If set to true, you will be prompted to install the Go language server. Once installed, you will have to reload VS Code window. The language server will then be run by the Go extension in the background to provide services needed for the above mentioned features.
• Every time you change the value of the setting go.useLanguageServer, you need to reload the VS Code window for it to take effect.
• To collect traces, set "go.languageServerFlags": ["-trace"]
• To collect errors from language server in a logfile, set "go.languageServerFlags": ["-trace", "-logfile", "path to a text file that exists"]
• Use the new setting go.languageServerExperimentalFeatures to opt-in to try new features like Code Completion and Formatting from the language server that might not be feature complete yet.

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 Go Meta Linter by setting go.lintTool to "gometalinter" in your settings.

Go meta linter uses a collection of various linters which will be installed for you by the extension.

Some of the very useful linter tools:

• errcheck checks for unchecked errors in your code.
• varcheck finds unused global variables and constants.
• deadcode finds unused code.

If you want to run only specific linters (some linters are slow), you can modify your configuration to specify them:

  "go.lintFlags": ["--disable=all", "--enable=errcheck"],

Alternatively, you can use megacheck which may have significantly better performance than gometalinter, while only supporting a subset of the tools.

Another alternative is golangci-lint which 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"],

An 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=${workspaceRoot}/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).

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 OS X 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.

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