adding initial support for third-party addons and the basic framework for how they are registered by the system

1 files changed, 155 insertions, 0 deletions

diff --git a/system/db/addon.go b/system/db/addon.go
new file mode 100644
index 0000000..da83b7f
--- /dev/null
+++ b/system/db/addon.go
@@ -0,0 +1,155 @@
+package db
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"log"
+	"net/url"
+
+	"github.com/boltdb/bolt"
+)
+
+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 url.Values representation of an addon
+func Addon(key string) (url.Values, 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
+	}
+
+	data, err := url.ParseQuery(buf.String())
+	if err != nil {
+		return nil, err
+	}
+
+	return data, nil
+}
+
+// SetAddon stores the values of an addon into the __addons bucket with a the
+// addon_reverse_dns field used as the key
+func SetAddon(data url.Values) error {
+	// we don't know the structure of the addon type from a addon developer, so
+	// encoding to json before it's stored in the db is difficult. Instead, we
+	// can just encode the url.Values to a query string using the Encode() method.
+	// The downside is that we will have to parse the values out of the query
+	// string when loading it from the db
+	v := data.Encode()
+
+	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), []byte(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() []url.Values {
+	var all []url.Values
+	buf := &bytes.Buffer{}
+
+	err := store.View(func(tx *bolt.Tx) error {
+		b := tx.Bucket([]byte("__addons"))
+		err := b.ForEach(func(k, v []byte) error {
+			_, err := buf.Write(v)
+			if err != nil {
+				return err
+			}
+
+			data, err := url.ParseQuery(buf.String())
+			if err != nil {
+				return err
+			}
+
+			all = append(all, data)
+			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
+	err := store.View(func(tx *bolt.Tx) error {
+		b := tx.Bucket([]byte("__addons"))
+		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
+}