Adds pm pull

remote/pull.go

@@ -1,8 +1,63 @@
 package remote
 
-import "github.com/pkg/errors"
+import (
+	"encoding/json"
+	"net/http"
+	"os"
+	"path/filepath"
+
+	"github.com/pkg/errors"
+	"mcquay.me/pm"
+)
+
+const an = "var/lib/pm/available.json"
 
 // Pull updates the available package database.
 func Pull(root string) error {
-	return errors.New("NYI")
+	db, err := load(root)
+	if err != nil {
+		return errors.Wrap(err, "loading db")
+	}
+
+	o := pm.Available{}
+
+	// Order here is important: the guarantee made is that any packages that
+	// exist in multiple remotes will be fetched by the first configured
+	// remote, which is why we traverse the database in reverse.
+	//
+	// TODO (sm): make this concurrent
+	for i := range db {
+		u := db[len(db)-i-1]
+		resp, err := http.Get(u.String() + "/available.json")
+		if err != nil {
+			return errors.Wrap(err, "http get")
+		}
+
+		a := pm.Available{}
+		if err := json.NewDecoder(resp.Body).Decode(&a); err != nil {
+			return errors.Wrap(err, "decode remote available")
+		}
+		a.SetRemote(u)
+		o.Update(a)
+	}
+	if err := saveAvailable(root, o); err != nil {
+		return errors.Wrap(err, "saving available db")
+	}
+	return nil
+}
+
+func saveAvailable(root string, db pm.Available) error {
+	f, err := os.Create(filepath.Join(root, an))
+	if err != nil {
+		return errors.Wrap(err, "create")
+	}
+	enc := json.NewEncoder(f)
+	enc.SetIndent("", "\t")
+	if err := enc.Encode(&db); err != nil {
+		return errors.Wrap(err, "decoding db")
+	}
+	if err := f.Close(); err != nil {
+		return errors.Wrap(err, "close db")
+	}
+	return nil
 }

remote/remote.go

@@ -15,7 +15,7 @@ import (
 // DB is a slice of available URI
 type DB []url.URL
 
-const fn = "var/lib/pm/available.json"
+const rn = "var/lib/pm/remotes.json"
 
 // Add appends the provided uri to the list of configured remotes.
 func Add(root string, uris []string) error {
@@ -93,13 +93,13 @@ func List(root string, w io.Writer) error {
 
 func load(root string) (DB, error) {
 	r := DB{}
-	dbn := filepath.Join(root, fn)
+	dbn := filepath.Join(root, rn)
 
 	if !fs.Exists(dbn) {
 		return r, nil
 	}
 
-	f, err := os.Open(filepath.Join(root, fn))
+	f, err := os.Open(filepath.Join(root, rn))
 	if err != nil {
 		return r, errors.Wrap(err, "open")
 	}
@@ -112,7 +112,7 @@ func load(root string) (DB, error) {
 }
 
 func save(root string, db DB) error {
-	f, err := os.Create(filepath.Join(root, fn))
+	f, err := os.Create(filepath.Join(root, rn))
 	if err != nil {
 		return errors.Wrap(err, "create")
 	}
@@ -140,7 +140,7 @@ func strip(u url.URL) url.URL {
 }
 
 func mkdirs(root string) error {
-	d, _ := filepath.Split(filepath.Join(root, fn))
+	d, _ := filepath.Split(filepath.Join(root, rn))
 	if !fs.Exists(d) {
 		if err := os.MkdirAll(d, 0700); err != nil {
 			return errors.Wrap(err, "mk pm dir")