[addons] Expanding basic addon framework (#29)

1 files changed, 151 insertions, 0 deletions

diff --git a/system/db/addon.go b/system/db/addon.go
new file mode 100644
index 0000000..f4621fa
--- /dev/null
+++ b/system/db/addon.go
@@ -0,0 +1,151 @@
+package db
+
+import (
+	"bytes"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"log"
+	"net/url"
+
+	"github.com/boltdb/bolt"
+	"github.com/gorilla/schema"
+)
+
+var (
+	// ErrNoAddonExists indicates that there was not addon found in the db
+	ErrNoAddonExists = errors.New("No addon exists.")
+)
+
+// Addon looks for an addon by its addon_reverse_dns as the key and returns
+// the []byte as json representation of an addon
+func Addon(key string) ([]byte, error) {
+	buf := &bytes.Buffer{}
+
+	err := store.View(func(tx *bolt.Tx) error {
+		b := tx.Bucket([]byte("__addons"))
+
+		val := b.Get([]byte(key))
+
+		if val == nil {
+			return ErrNoAddonExists
+		}
+
+		_, err := buf.Write(val)
+		if err != nil {
+			return err
+		}
+
+		return nil
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	return buf.Bytes(), nil
+}
+
+// SetAddon stores the values of an addon into the __addons bucket with a the
+// `addon_reverse_dns` field used as the key. `kind` is the interface{} type for
+// the provided addon (as in the result of calling addon.Types[id])
+func SetAddon(data url.Values, kind interface{}) error {
+	dec := schema.NewDecoder()
+	dec.IgnoreUnknownKeys(true)
+	dec.SetAliasTag("json")
+	err := dec.Decode(kind, data)
+
+	v, err := json.Marshal(kind)
+
+	err = store.Update(func(tx *bolt.Tx) error {
+		b := tx.Bucket([]byte("__addons"))
+		k := data.Get("addon_reverse_dns")
+		if k == "" {
+			name := data.Get("addon_name")
+			return fmt.Errorf(`Addon "%s" has no identifier to use as key.`, name)
+		}
+
+		err := b.Put([]byte(k), v)
+		if err != nil {
+			return err
+		}
+
+		return nil
+	})
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// AddonAll returns all registered addons as a [][]byte
+func AddonAll() [][]byte {
+	var all [][]byte
+
+	err := store.View(func(tx *bolt.Tx) error {
+		b := tx.Bucket([]byte("__addons"))
+		err := b.ForEach(func(k, v []byte) error {
+			all = append(all, v)
+
+			return nil
+		})
+		if err != nil {
+			return err
+		}
+
+		return nil
+	})
+	if err != nil {
+		log.Println("Error finding addons in db with db.AddonAll:", err)
+		return nil
+	}
+
+	return all
+}
+
+// DeleteAddon removes an addon from the db by its key, the addon_reverse_dns
+func DeleteAddon(key string) error {
+	err := store.Update(func(tx *bolt.Tx) error {
+		b := tx.Bucket([]byte("__addons"))
+
+		if err := b.Delete([]byte(key)); err != nil {
+			return err
+		}
+
+		return nil
+	})
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// AddonExists checks if there is an existing addon stored. The key is an the
+// value at addon_reverse_dns
+func AddonExists(key string) bool {
+	var exists bool
+
+	if store == nil {
+		Init()
+	}
+
+	err := store.Update(func(tx *bolt.Tx) error {
+		b, err := tx.CreateBucketIfNotExists([]byte("__addons"))
+		if err != nil {
+			return err
+		}
+		if b.Get([]byte(key)) == nil {
+			return nil
+		}
+
+		exists = true
+		return nil
+	})
+	if err != nil {
+		log.Println("Error checking existence of addon with key:", key, "-", err)
+		return false
+	}
+
+	return exists
+}