Add ApiURI for gitlab provider (#27)

* Add ApiURI for gitlab provider
it can let us using private server

* Increase code coverage for provider_gitlab.go

---------

Co-authored-by: Julien NOBLET <julien.noblet@gls-france.com>

pkg/provider/provider_gitlab.go

@@ -17,6 +17,7 @@ import (
 type Gitlab struct {
 	ProjectID   int
 	ArchiveName string // ArchiveName (the archive you upload for a release on gitlab), example: binaries.zip
+	ApiURI      string // ApiURI (in case you're using a private gitlab server), example: gitlab.mydomain.tld/api/v4/projects/%d/releases to use gitlab.com let it blank
 
 	tmpDir             string   // temporary directory this is used internally
 	decompressProvider Provider // provider used to decompress the downloaded archive
@@ -41,6 +42,12 @@ type gitlabReleaseLink struct {
 
 // getReleasesURL get the releases URL for the gitlab repository
 func (c *Gitlab) getReleasesURL() (string, error) {
+	if c.ApiURI != "" {
+		return fmt.Sprintf(c.ApiURI,
+			c.ProjectID,
+		), nil
+	}
+
 	return fmt.Sprintf("https://gitlab.com/api/v4/projects/%d/releases",
 		c.ProjectID,
 	), nil

pkg/provider/provider_gitlab_test.go

@@ -24,6 +24,22 @@ func TestProviderGitlab(t *testing.T) {
 		t.Fatal(err)
 	}
 
+	pp := &provider.Gitlab{
+		ProjectID:   24021648,
+		ArchiveName: fmt.Sprintf("binaries_%s.zip", runtime.GOOS),
+		ApiURI:      "https://gitlab.com/api/v4/projects/%d/releases", // same as original
+	}
+
+	if err := pp.Open(); err != nil {
+		t.Fatal(err)
+	}
+	defer pp.Close()
+
+	err = ProviderTestWalkAndRetrieve(pp)
+	if err != nil {
+		t.Fatal(err)
+	}
+
 	badProvider := &provider.Gitlab{
 		ProjectID:   424242424242424242,
 		ArchiveName: fmt.Sprintf("binaries_%s.zip", runtime.GOOS),
@@ -32,4 +48,14 @@ func TestProviderGitlab(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
+
+	badProviderApi := &provider.Gitlab{
+		ProjectID:   24021648,
+		ArchiveName: fmt.Sprintf("binaries_%s.zip", runtime.GOOS),
+		ApiURI:      "https://bad.url/api/%d/R",
+	}
+	err = ProviderTestUnavailable(badProviderApi)
+	if err != nil {
+		t.Fatal(err)
+	}
 }