feat: add gitlab source for gitlab package registry

cleanup http source

pkg/gitlab_registry.go

@@ -0,0 +1,77 @@
+// Copyright 2018 jsonnet-bundler authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package pkg
+
+import (
+	"context"
+	"github.com/jsonnet-bundler/jsonnet-bundler/spec/v1/deps"
+	"net/url"
+	"os"
+	"path"
+)
+
+type GitlabRegistryPackage struct {
+	Source *deps.GitlabRegistry
+}
+
+func NewGitlabRegistryPackage(source *deps.GitlabRegistry) Interface {
+	return &GitlabRegistryPackage{
+		Source: source,
+	}
+}
+
+func buildUrl(src *deps.GitlabRegistry, version string) url.URL {
+	host := "gitlab.com"
+	if src.Host != "" {
+		host = src.Host
+	}
+	filename := "package.tar.gz"
+	if src.Filename != "" {
+		filename = src.Filename
+	}
+
+	packageUrl := url.URL{
+		Scheme: "https",
+		Host:   host,
+	}
+	// this way is needed so that net/url does not double encode '/' to '%252F'
+	return *packageUrl.JoinPath(
+		"api/v4/projects",
+		url.PathEscape(src.Project),
+		"packages/generic",
+		src.Package,
+		version,
+		filename,
+	)
+}
+
+func (h *GitlabRegistryPackage) Install(ctx context.Context, name, dir, version string) (string, error) {
+	destPath := path.Join(dir, name)
+
+	packageUrl := buildUrl(h.Source, version)
+
+	tmpDir, err := CreateTempDir(name, dir, version)
+	if err != nil {
+		return "", err
+	}
+	defer os.RemoveAll(tmpDir)
+
+	err = DownloadAndUntarTo(tmpDir, packageUrl.String(), destPath)
+	if err != nil {
+		return "", err
+	}
+
+	return version, nil
+}