feat: improve plugin preload logic

* Allow '*' meaning "load all plugins".
* Expose a Preload function that users can call.

plugin/loader/loader.go

@@ -15,6 +15,13 @@ import (
 	opentracing "github.com/opentracing/opentracing-go"
 )
 
+var preloadPlugins []plugin.Plugin
+
+// Preload adds one or more plugins to the preload list. This should _only_ be called during init.
+func Preload(plugins ...plugin.Plugin) {
+	preloadPlugins = append(preloadPlugins, plugins...)
+}
+
 var log = logging.Logger("plugin/loader")
 
 var loadPluginsFunc = func(string) ([]plugin.Plugin, error) {

plugin/loader/preload.go

 package loader
 
 import (
-	"github.com/ipfs/go-ipfs/plugin"
 	pluginbadgerds "github.com/ipfs/go-ipfs/plugin/plugins/badgerds"
 	pluginflatfs "github.com/ipfs/go-ipfs/plugin/plugins/flatfs"
 	pluginipldgit "github.com/ipfs/go-ipfs/plugin/plugins/git"
@@ -12,9 +11,9 @@ import (
 // This file is being generated as part of plugin build process
 // To change it, modify the plugin/loader/preload.sh
 
-var preloadPlugins = []plugin.Plugin{
-	pluginipldgit.Plugins[0],
-	pluginbadgerds.Plugins[0],
-	pluginflatfs.Plugins[0],
-	pluginlevelds.Plugins[0],
+func init() {
+	Preload(pluginipldgit.Plugins...)
+	Preload(pluginbadgerds.Plugins...)
+	Preload(pluginflatfs.Plugins...)
+	Preload(pluginlevelds.Plugins...)
 }

plugin/loader/preload.sh

@@ -10,7 +10,6 @@ cat <<EOL
 package loader
 
 import (
-	"github.com/ipfs/go-ipfs/plugin"
 EOL
 
 to_preload | while read -r name path num; do
@@ -25,12 +24,14 @@ cat <<EOL
 // This file is being generated as part of plugin build process
 // To change it, modify the plugin/loader/preload.sh
 
-var preloadPlugins = []plugin.Plugin{
+func init() {
 EOL
 
 to_preload | while read -r name path num; do
-	echo "plugin$name.Plugins[$num],"
+	case "$num" in
+		'*') echo "	Preload(plugin$name.Plugins...)" ;; # All plugins
+		*) echo "	Preload(plugin$name.Plugins[$num])" ;; # A specific plugin
+	esac
 done
 
-
 echo "}"

plugin/loader/preload_list

 # this file contains plugins to be preloaded
 # empty lines or starting with '#' are ignored
 #
-# name             go-path                  number of the sub-plugin
+# name             go-path                  number of the sub-plugin or *
 
-ipldgit github.com/ipfs/go-ipfs/plugin/plugins/git 0
+ipldgit github.com/ipfs/go-ipfs/plugin/plugins/git *
 
-badgerds github.com/ipfs/go-ipfs/plugin/plugins/badgerds 0
-flatfs github.com/ipfs/go-ipfs/plugin/plugins/flatfs 0
-levelds github.com/ipfs/go-ipfs/plugin/plugins/levelds 0
+badgerds github.com/ipfs/go-ipfs/plugin/plugins/badgerds *
+flatfs github.com/ipfs/go-ipfs/plugin/plugins/flatfs *
+levelds github.com/ipfs/go-ipfs/plugin/plugins/levelds *