Package documentation pages automatically link identifiers and file names to source code hosted on version control services known to GoDoc.org.

The go-source meta tag is used to specify links to source code on services not known to GoDoc.org. The go-source meta tag is similar to the vanity path go-import meta tag and is specified in the same resource as the go-import meta tag.

The structure of the go-source meta tag is:

<meta name="go-source" content="prefix home directory file">

The prefix field is the import path corresponding to the repository root.

The home field is the URL of the repository's home page.

The directory field is a URL template for a page listing the files in the package. The following substitutions are made in the directory template:

{dir} - The import path with prefix and leading "/" trimmed.
{/dir} - If {dir} is not the empty string, then {/dir} is replaced by "/" +
         {dir}. Otherwise, {/dir} is replaced with the empty string.

The file field is a URL template for a link to a line in a source file. The following substitutions are made in the file template:

{file} - The name of the file
{line} - The decimal line number.

Note: The current implementation imposes a few additional restrictions to the description above. In order for the file field to have an effect (and not have unexpected adverse effects), these rules must be followed until the implementation is fixed (see TODO comment and comments in #385 for context):

• The file field URL template must contain at least one instance of {file}.
• The {line} component is optional, but if it is to be included, then the file field must contain # and the instance of {line} must be after the #. Instances of {line} that come before # will not be substituted.
• In order for {line} substitutions to be made, no more than one instance of {line} must appear in the file field after #.
• It's okay for % to be present after #, but not before.

The meta tag content attribute must contain four fields. Use "_" to fallback to GoDoc.org's defaults for home, directory and file.

Here's an example of the go-import and go-source meta tags for the gopkg.in/yaml.v2 package:

<meta name="go-import"
    content="gopkg.in/yaml.v2 git https://gopkg.in/yaml.v2">
<meta name="go-source"
    content="gopkg.in/yaml.v2 _ https://github.com/go-yaml/yaml/tree/v2{/dir} https://github.com/go-yaml/yaml/blob/v2{/dir}/{file}#L{line}">