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tianxiaoliang pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/servicecomb-service-center.git
The following commit(s) were added to refs/heads/master by this push:
new 286c8e7 Add comments for plugin pkg, to be easier to understand the
code (#609)
286c8e7 is described below
commit 286c8e7934ad983df5a5a1c642a0634e523cfe13
Author: humingcheng <[email protected]>
AuthorDate: Wed Dec 18 14:09:43 2019 +0800
Add comments for plugin pkg, to be easier to understand the code (#609)
---
server/plugin/export.go | 2 +-
server/plugin/pkg/discovery/aggregate/adaptor.go | 2 +-
server/plugin/plugin.go | 43 ++++++++++++++++++++----
server/plugin/types.go | 26 ++++++++++----
4 files changed, 58 insertions(+), 15 deletions(-)
diff --git a/server/plugin/export.go b/server/plugin/export.go
index b110ea6..80e5540 100644
--- a/server/plugin/export.go
+++ b/server/plugin/export.go
@@ -37,7 +37,7 @@ const (
TRACING
TLS
DISCOVERY
- typeEnd
+ typeEnd // for counting
)
var pluginNames = map[PluginName]string{
diff --git a/server/plugin/pkg/discovery/aggregate/adaptor.go
b/server/plugin/pkg/discovery/aggregate/adaptor.go
index e56e7c3..3ff356d 100644
--- a/server/plugin/pkg/discovery/aggregate/adaptor.go
+++ b/server/plugin/pkg/discovery/aggregate/adaptor.go
@@ -84,7 +84,7 @@ func getLogConflictFunc(t discovery.Type) func(origin,
conflict *discovery.KeyVa
func NewAggregator(t discovery.Type, cfg *discovery.Config) *Aggregator {
as := &Aggregator{Type: t}
for _, name := range repos {
- repo := mgr.Plugins().Get(mgr.DISCOVERY,
name).New().(discovery.AdaptorRepository)
+ repo := mgr.Plugins().Get(mgr.DISCOVERY,
mgr.PluginImplName(name)).New().(discovery.AdaptorRepository)
as.Adaptors = append(as.Adaptors, repo.New(t, cfg))
}
as.Indexer = NewAggregatorIndexer(as)
diff --git a/server/plugin/plugin.go b/server/plugin/plugin.go
index 4a45741..e4027c5 100644
--- a/server/plugin/plugin.go
+++ b/server/plugin/plugin.go
@@ -17,11 +17,13 @@
package plugin
import (
+ "sync"
+
"github.com/apache/servicecomb-service-center/pkg/log"
"github.com/apache/servicecomb-service-center/pkg/plugin"
"github.com/apache/servicecomb-service-center/pkg/util"
+
"github.com/astaxie/beego"
- "sync"
)
var pluginMgr = &PluginManager{}
@@ -36,13 +38,17 @@ type wrapInstance struct {
lock sync.RWMutex
}
+// PluginManager manages plugin instance generation.
+// PluginManager keeps the plugin instance currently used by server
+// for every plugin interface.
type PluginManager struct {
- plugins map[PluginName]map[string]*Plugin
+ plugins map[PluginName]map[PluginImplName]*Plugin
instances map[PluginName]*wrapInstance
}
+// Initialize initializes the struct
func (pm *PluginManager) Initialize() {
- pm.plugins = make(map[PluginName]map[string]*Plugin, int(typeEnd))
+ pm.plugins = make(map[PluginName]map[PluginImplName]*Plugin,
int(typeEnd))
pm.instances = make(map[PluginName]*wrapInstance, int(typeEnd))
for t := PluginName(0); t != typeEnd; t++ {
@@ -50,24 +56,27 @@ func (pm *PluginManager) Initialize() {
}
}
+// ReloadAll reloads all the plugin instances
func (pm *PluginManager) ReloadAll() {
for pn := range pm.instances {
pm.Reload(pn)
}
}
+// Register registers a 'Plugin'
// unsafe
func (pm *PluginManager) Register(p Plugin) {
m, ok := pm.plugins[p.PName]
if !ok {
- m = make(map[string]*Plugin, 5)
+ m = make(map[PluginImplName]*Plugin, 5)
}
m[p.Name] = &p
pm.plugins[p.PName] = m
log.Infof("load '%s' plugin named '%s'", p.PName, p.Name)
}
-func (pm *PluginManager) Get(pn PluginName, name string) *Plugin {
+// Get gets a 'Plugin'
+func (pm *PluginManager) Get(pn PluginName, name PluginImplName) *Plugin {
m, ok := pm.plugins[pn]
if !ok {
return nil
@@ -75,6 +84,19 @@ func (pm *PluginManager) Get(pn PluginName, name string)
*Plugin {
return m[name]
}
+// Instance gets an plugin instance.
+// What plugin instance you get is depended on the supplied go plugin files
+// (high priority) or the plugin config(low priority)
+//
+// The go plugin file should be {plugins_dir}/{PluginName}_plugin.so.
+// ('plugins_dir' must be configured as a valid path in service-center config.)
+// The plugin config in service-center config should be:
+// {PluginName}_plugin = {PluginImplName}
+//
+// e.g. For registry plugin, you can set a config in app.conf:
+// plugins_dir = /home, and supply a go plugin file: /home/registry_plugin.so;
+// or if you want to use etcd as registry, you can set a config in app.conf:
+// registry_plugin = etcd.
func (pm *PluginManager) Instance(pn PluginName) PluginInstance {
wi := pm.instances[pn]
wi.lock.RLock()
@@ -95,6 +117,10 @@ func (pm *PluginManager) Instance(pn PluginName)
PluginInstance {
return wi.instance
}
+// New initializes and sets the instance of a plugin interface,
+// but not returns it.
+// Use 'Instance' if you want to get the plugin instance.
+// We suggest you to use 'Instance' instead of 'New'.
func (pm *PluginManager) New(pn PluginName) {
var (
title = STATIC
@@ -104,6 +130,7 @@ func (pm *PluginManager) New(pn PluginName) {
wi := pm.instances[pn]
p := pm.existDynamicPlugin(pn)
if p != nil {
+ // Dynamic plugin has high priority.
wi.dynamic = true
title = DYNAMIC
f = p.New
@@ -115,7 +142,7 @@ func (pm *PluginManager) New(pn PluginName) {
}
name := beego.AppConfig.DefaultString(pn.String()+"_plugin",
BUILDIN)
- p, ok = m[name]
+ p, ok = m[PluginImplName(name)]
if !ok {
return
}
@@ -129,6 +156,7 @@ func (pm *PluginManager) New(pn PluginName) {
wi.instance = f()
}
+// Reload reloads the instance of the specified plugin interface.
func (pm *PluginManager) Reload(pn PluginName) {
wi := pm.instances[pn]
wi.lock.Lock()
@@ -149,14 +177,17 @@ func (pm *PluginManager) existDynamicPlugin(pn
PluginName) *Plugin {
return nil
}
+// Plugins returns the 'PluginManager'.
func Plugins() *PluginManager {
return pluginMgr
}
+// RegisterPlugin registers a 'Plugin'.
func RegisterPlugin(p Plugin) {
Plugins().Register(p)
}
+// LoadPlugins loads and sets all the plugin interfaces's instance.
func LoadPlugins() {
for t := PluginName(0); t != typeEnd; t++ {
Plugins().Instance(t)
diff --git a/server/plugin/types.go b/server/plugin/types.go
index be1ffd5..30c3208 100644
--- a/server/plugin/types.go
+++ b/server/plugin/types.go
@@ -16,15 +16,23 @@
package plugin
import (
+ "strconv"
+
"github.com/apache/servicecomb-service-center/pkg/util"
"github.com/apache/servicecomb-service-center/server/core"
- "strconv"
)
-type PluginInstance interface{}
-
+// PluginName is an alias, it represents a plugin interface.
type PluginName int
+// PluginImplName is an alias，it represents a plugin interface implementation.
+type PluginImplName string
+
+// PluginInstance is an instance of a plugin interface which is represented by
+// PluginName.
+type PluginInstance interface{}
+
+// String implements fmt.Stringer.
func (pn PluginName) String() string {
if name, ok := pluginNames[pn]; ok {
return name
@@ -32,18 +40,22 @@ func (pn PluginName) String() string {
return "PLUGIN" + strconv.Itoa(int(pn))
}
+// ActiveConfigs returns all the server's plugin config
func (pn PluginName) ActiveConfigs() util.JSONObject {
return core.ServerInfo.Config.Plugins.Object(pn.String())
}
+// ClearConfigs clears the server's plugin config
func (pn PluginName) ClearConfigs() {
core.ServerInfo.Config.Plugins.Set(pn.String(), nil)
}
+// Plugin generates a plugin instance
+// Plugin holds the 'PluginName' and 'PluginImplName'
+// to manage the plugin instance generation.
type Plugin struct {
- // plugin class name
PName PluginName
- // plugin name
- Name string
- New func() PluginInstance
+ Name PluginImplName
+ // New news an instance of 'PName' represented plugin interface
+ New func() PluginInstance
}
