pm install downloads packages

meta.go

@@ -29,9 +29,14 @@ func (m Meta) Valid() (bool, error) {
 	return true, nil
 }
 
+// Pkg returns the string name the .pkg should have on disk.
+func (m Meta) Pkg() string {
+	return fmt.Sprintf("%s-%s.pkg", m.Name, m.Version)
+}
+
 // URL returns the http location of this package.
 func (m Meta) URL() string {
-	return fmt.Sprintf("%s/%s-%s.pkg", m.Remote.String(), m.Name, m.Version)
+	return fmt.Sprintf("%s/%s", m.Remote.String(), m.Pkg())
 }
 
 func (m Meta) String() string {

pkg/install.go

@@ -1,12 +1,19 @@
 package pkg
 
 import (
-	"log"
+	"io"
+	"net/http"
+	"os"
+	"path/filepath"
 
 	"github.com/pkg/errors"
+	"mcquay.me/fs"
+	"mcquay.me/pm"
 	"mcquay.me/pm/db"
 )
 
+const cache = "var/cache/pm"
+
 // Install fetches and installs pkgs from appropriate remotes.
 func Install(root string, pkgs []string) error {
 	av, err := db.LoadAvailable(root)
@@ -18,8 +25,44 @@ func Install(root string, pkgs []string) error {
 	if err != nil {
 		return errors.Wrap(err, "checking ability to install")
 	}
-	for _, m := range ms {
-		log.Printf("fake install %v", m)
+
+	cacheDir := filepath.Join(root, cache)
+	if !fs.Exists(cacheDir) {
+		if err := os.MkdirAll(cacheDir, 0755); err != nil {
+			return errors.Wrap(err, "creating non-existent cache dir")
+		}
 	}
+	if !fs.IsDir(cacheDir) {
+		return errors.Errorf("%q is not a directory!", cacheDir)
+	}
+
+	if err := download(cacheDir, ms); err != nil {
+		return errors.Wrap(err, "downloading")
+	}
+
 	return errors.New("NYI")
 }
+
+func download(cache string, ms pm.Metas) error {
+	// TODO (sm): concurrently fetch
+	for _, m := range ms {
+		resp, err := http.Get(m.URL())
+		if err != nil {
+			return errors.Wrap(err, "http get")
+		}
+		fn := filepath.Join(cache, m.Pkg())
+		f, err := os.Create(fn)
+		if err != nil {
+			return errors.Wrap(err, "creating")
+		}
+
+		if n, err := io.Copy(f, resp.Body); err != nil {
+			return errors.Wrapf(err, "copy %q to disk after %d bytes", m.URL(), n)
+		}
+
+		if err := resp.Body.Close(); err != nil {
+			return errors.Wrap(err, "closing resp body")
+		}
+	}
+	return nil
+}