feat: add http source with support for environment variables

pkg/http.go

@@ -0,0 +1,106 @@
+// 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"
+	"crypto/sha256"
+	"encoding/hex"
+	"fmt"
+	"github.com/jsonnet-bundler/jsonnet-bundler/spec/v1/deps"
+	"github.com/pkg/errors"
+	"io"
+	"io/ioutil"
+	"net/http"
+	"os"
+	"path"
+	"path/filepath"
+	"strings"
+)
+
+type HttpPackage struct {
+	Source *deps.Http
+}
+
+func NewHttpPackage(source *deps.Http) Interface {
+	return &HttpPackage{
+		Source: source,
+	}
+}
+
+func downloadFile(filepath string, url string) error {
+	resp, err := http.Get(url)
+	if err != nil {
+		return err
+	}
+
+	if resp.StatusCode != 200 {
+		return fmt.Errorf("unexpected status code %d", resp.StatusCode)
+	}
+
+	defer resp.Body.Close()
+
+	// Create the file
+	out, err := os.Create(filepath)
+	if err != nil {
+		return err
+	}
+	defer out.Close()
+
+	// Write the body to file
+	_, err = io.Copy(out, resp.Body)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (h *HttpPackage) Install(ctx context.Context, name, dir, version string) (string, error) {
+	destPath := path.Join(dir, name)
+
+	pkgh := sha256.Sum256([]byte(fmt.Sprintf("jsonnetpkg-%s-%s", strings.Replace(name, "/", "-", -1), strings.Replace(version, "/", "-", -1))))
+	// using 16 bytes should be a good middle ground between length and collision resistance
+	tmpDir, err := ioutil.TempDir(filepath.Join(dir, ".tmp"), hex.EncodeToString(pkgh[:16]))
+	if err != nil {
+		return "", errors.Wrap(err, "failed to create tmp dir")
+	}
+	defer os.RemoveAll(tmpDir)
+
+	err = os.Setenv("VERSION", version)
+	if err != nil {
+		return "", err
+	}
+	url := os.ExpandEnv(h.Source.Url)
+
+	filename := filepath.Base(url)
+	err = downloadFile(path.Join(tmpDir, filename), url)
+	if err != nil {
+		return "", errors.Wrap(err, "failed to download file")
+	}
+
+	var ar *os.File
+	ar, err = os.Open(path.Join(tmpDir, filename))
+	if err != nil {
+		return "", errors.Wrap(err, "failed to open downloaded archive")
+	}
+	defer ar.Close()
+	err = GzipUntar(destPath, ar, "")
+	if err != nil {
+		return "", errors.Wrap(err, "failed to unpack downloaded archive")
+	}
+
+	return version, nil
+}