add getter package, a thin wrapper of go-getter

client/getter/getter.go

@@ -0,0 +1,44 @@
+package getter
+
+import (
+	"fmt"
+	"log"
+	"net/url"
+	"path"
+	"path/filepath"
+	"runtime"
+	"strings"
+	"syscall"
+
+	gg "github.com/hashicorp/go-getter"
+)
+
+func GetArtifact(destDir, source, checksum string, logger *log.Logger) (string, error) {
+	// We use go-getter to support a variety of protocols, but need to change
+	// file permissions of the resulted download to be executable
+
+	u, err := url.Parse(source)
+	if err != nil {
+		return "", err
+	}
+
+	// look for checksum, apply to URL
+	if checksum != "" {
+		source = strings.Join([]string{source, fmt.Sprintf("checksum=%s", checksum)}, "?")
+		logger.Printf("[DEBUG] Applying checksum to Artifact Source URL, new url: %s", source)
+	}
+
+	artifactName := path.Base(u.Path)
+	artifactFile := filepath.Join(destDir, artifactName)
+	if err := gg.GetFile(artifactFile, source); err != nil {
+		return "", fmt.Errorf("Error downloading artifact: %s", err)
+	}
+
+	// Add execution permissions to the newly downloaded artifact
+	if runtime.GOOS != "windows" {
+		if err := syscall.Chmod(artifactFile, 0755); err != nil {
+			logger.Printf("[ERR] driver.raw_exec: Error making artifact executable: %s", err)
+		}
+	}
+	return artifactFile, nil
+}

client/getter/getter_test.go

@@ -0,0 +1,103 @@
+package getter
+
+import (
+	"fmt"
+	"io/ioutil"
+	"log"
+	"os"
+	"strings"
+	"testing"
+)
+
+func TestGetArtifact_basic(t *testing.T) {
+
+	logger := log.New(os.Stderr, "", log.LstdFlags)
+
+	// TODO: Use http.TestServer to serve these files from fixtures dir
+	passing := []struct {
+		Source, Checksum string
+	}{
+		{
+			"https://dl.dropboxusercontent.com/u/47675/jar_thing/hi_darwin_amd64",
+			"sha256:66aa0f05fc0cfcf1e5ed8cc5307b5df51e33871d6b295a60e0f9f6dd573da977",
+		},
+		{
+			"https://dl.dropboxusercontent.com/u/47675/jar_thing/hi_linux_amd64",
+			"sha256:6f99b4c5184726e601ecb062500aeb9537862434dfe1898dbe5c68d9f50c179c",
+		},
+		{
+			"https://dl.dropboxusercontent.com/u/47675/jar_thing/hi_linux_amd64",
+			"md5:a9b14903a8942748e4f8474e11f795d3",
+		},
+		{
+			"https://dl.dropboxusercontent.com/u/47675/jar_thing/hi_linux_amd64?checksum=sha256:6f99b4c5184726e601ecb062500aeb9537862434dfe1898dbe5c68d9f50c179c",
+			"",
+		},
+		{
+			"https://dl.dropboxusercontent.com/u/47675/jar_thing/hi_linux_amd64",
+			"",
+		},
+	}
+
+	for i, p := range passing {
+		destDir, err := ioutil.TempDir("", fmt.Sprintf("nomad-test-%d", i))
+		if err != nil {
+			t.Fatalf("Error in TestGetArtifact_basic makeing TempDir: %s", err)
+		}
+
+		path, err := GetArtifact(destDir, p.Source, p.Checksum, logger)
+		if err != nil {
+			t.Fatalf("TestGetArtifact_basic unexpected failure here: %s", err)
+		}
+
+		if p.Checksum != "" {
+			if ok := strings.Contains(path, p.Checksum); ok {
+				t.Fatalf("path result should not contain the checksum, got: %s", path)
+			}
+		}
+
+		// verify artifact exists
+		if _, err := os.Stat(path); err != nil {
+			t.Fatalf("source path error: %s", err)
+		}
+	}
+}
+
+func TestGetArtifact_fails(t *testing.T) {
+
+	logger := log.New(os.Stderr, "", log.LstdFlags)
+
+	failing := []struct {
+		Source, Checksum string
+	}{
+		{
+			"https://dl.dropboxusercontent.com/u/47675/jar_thing/hi_darwin_amd64",
+			"sha256:66aa0f05fc0cfcf1e5ed8cc5307b5d",
+		},
+		{
+			"https://dl.dropboxusercontent.com/u/47675/jar_thing/hi_linux_amd64",
+			"sha257:6f99b4c5184726e601ecb062500aeb9537862434dfe1898dbe5c68d9f50c179c",
+		},
+		// malformed checksum
+		{
+			"https://dl.dropboxusercontent.com/u/47675/jar_thing/hi_linux_amd64",
+			"6f99b4c5184726e601ecb062500aeb9537862434dfe1898dbe5c68d9f50c179c",
+		},
+		// 404
+		{
+			"https://dl.dropboxusercontent.com/u/47675/jar_thing/hi_linux_amd86",
+			"",
+		},
+	}
+	for i, p := range failing {
+		destDir, err := ioutil.TempDir("", fmt.Sprintf("nomad-test-%d", i))
+		if err != nil {
+			t.Fatalf("Error in TestGetArtifact_basic makeing TempDir: %s", err)
+		}
+
+		_, err = GetArtifact(destDir, p.Source, p.Checksum, logger)
+		if err == nil {
+			t.Fatalf("TestGetArtifact_basic expected failure, but got none")
+		}
+	}
+}