Fix gitlab-shell not handling relative URLs over UNIX socketssh-fix-unix-relative-url-access

From
https://gitlab.com/gitlab-org/omnibus-gitlab/-/merge_requests/4498#note_397401883,
if you specify a relative path such as:

```
external_url 'http://gitlab.example.com/gitlab'
```

gitlab-shell doesn't have a way to pass the `/gitlab` to the host. For example, let's say we have:

```
gitlab_url: "http+unix://%2Fvar%2Fopt%2Fgitlab%2Fgitlab-workhorse%2Fsocket"
```

If we have `/gitlab` as the relative path, how do we specify what is the
UNIX socket path and what is the relative path? If we specify:

```
gitlab_url: "http+unix:///var/opt/gitlab/gitlab-workhorse.socket/gitlab
```

This is ambiguous. Is the socket in
`/var/opt/gitlab/gitlab-workhorse.socket/gitlab` or in
`/var/opt/gitlab/gitlab-workhorse.socket`?

To fix this, this merge request adds an optional
`gitlab_relative_url_root` config parameter:

```
gitlab_url: "http+unix://%2Fvar%2Fopt%2Fgitlab%2Fgitlab-workhorse%2Fsocket"
gitlab_relative_url_root: /gitlab
```

This is only used with UNIX domain sockets to disambiguate the socket
and base URL path. If `gitlab_url` uses `http://` or `https://`, then
`gitlab_relative_url_root` is ignored.

Relates to https://gitlab.com/gitlab-org/gitlab-shell/-/issues/476

1 files changed, 11 insertions, 5 deletions

diff --git a/client/httpclient.go b/client/httpclient.go
index 63386f7..6635f1b 100644
--- a/client/httpclient.go
+++ b/client/httpclient.go
@@ -27,12 +27,12 @@ type HttpClient struct {
 	Host string
 }
 
-func NewHTTPClient(gitlabURL, caFile, caPath string, selfSignedCert bool, readTimeoutSeconds uint64) *HttpClient {
+func NewHTTPClient(gitlabURL, gitlabRelativeURLRoot, caFile, caPath string, selfSignedCert bool, readTimeoutSeconds uint64) *HttpClient {
 
 	var transport *http.Transport
 	var host string
 	if strings.HasPrefix(gitlabURL, unixSocketProtocol) {
-		transport, host = buildSocketTransport(gitlabURL)
+		transport, host = buildSocketTransport(gitlabURL, gitlabRelativeURLRoot)
 	} else if strings.HasPrefix(gitlabURL, httpProtocol) {
 		transport, host = buildHttpTransport(gitlabURL)
 	} else if strings.HasPrefix(gitlabURL, httpsProtocol) {
@@ -41,7 +41,6 @@ func NewHTTPClient(gitlabURL, caFile, caPath string, selfSignedCert bool, readTi
 		return nil
 	}
 
-
 	c := &http.Client{
 		Transport: correlation.NewInstrumentedRoundTripper(transport),
 		Timeout:   readTimeout(readTimeoutSeconds),
@@ -52,8 +51,9 @@ func NewHTTPClient(gitlabURL, caFile, caPath string, selfSignedCert bool, readTi
 	return client
 }
 
-func buildSocketTransport(gitlabURL string) (*http.Transport, string) {
+func buildSocketTransport(gitlabURL, gitlabRelativeURLRoot string) (*http.Transport, string) {
 	socketPath := strings.TrimPrefix(gitlabURL, unixSocketProtocol)
+
 	transport := &http.Transport{
 		DialContext: func(ctx context.Context, _, _ string) (net.Conn, error) {
 			dialer := net.Dialer{}
@@ -61,7 +61,13 @@ func buildSocketTransport(gitlabURL string) (*http.Transport, string) {
 		},
 	}
 
-	return transport, socketBaseUrl
+	host := socketBaseUrl
+	gitlabRelativeURLRoot = strings.Trim(gitlabRelativeURLRoot, "/")
+	if gitlabRelativeURLRoot != "" {
+		host = host + "/" + gitlabRelativeURLRoot
+	}
+
+	return transport, host
 }
 
 func buildHttpsTransport(caFile, caPath string, selfSignedCert bool, gitlabURL string) (*http.Transport, string) {