1 files changed, 60 insertions, 17 deletions

diff --git a/plugin/example_help_test.go b/plugin/example_help_test.go
index 175b6588e..e4aa9dec3 100644
--- a/plugin/example_help_test.go
+++ b/plugin/example_help_test.go
@@ -2,48 +2,91 @@ package plugin_test
 
 import (
 	"strings"
+	"sync"
+
+	"github.com/pkg/errors"
 
 	"github.com/mattermost/mattermost-server/model"
 	"github.com/mattermost/mattermost-server/plugin"
 )
 
-type HelpPlugin struct {
-	plugin.MattermostPlugin
-
+// configuration represents the configuration for this plugin as exposed via the Mattermost
+// server configuration.
+type configuration struct {
 	TeamName    string
 	ChannelName string
 
+	// channelId is resolved when the public configuration fields above change
 	channelId string
 }
 
+type HelpPlugin struct {
+	plugin.MattermostPlugin
+
+	// configurationLock synchronizes access to the configuration.
+	configurationLock sync.RWMutex
+
+	// configuration is the active plugin configuration. Consult getConfiguration and
+	// setConfiguration for usage.
+	configuration *configuration
+}
+
+// getConfiguration retrieves the active configuration under lock, making it safe to use
+// concurrently. The active configuration may change underneath the client of this method, but
+// the struct returned by this API call is considered immutable.
+func (p *HelpPlugin) getConfiguration() *configuration {
+	p.configurationLock.RLock()
+	defer p.configurationLock.RUnlock()
+
+	if p.configuration == nil {
+		return &configuration{}
+	}
+
+	return p.configuration
+}
+
+// setConfiguration replaces the active configuration under lock.
+//
+// Do not call setConfiguration while holding the configurationLock, as sync.Mutex is not
+// reentrant.
+func (p *HelpPlugin) setConfiguration(configuration *configuration) {
+	// Replace the active configuration under lock.
+	p.configurationLock.Lock()
+	defer p.configurationLock.Unlock()
+	p.configuration = configuration
+}
+
+// OnConfigurationChange updates the active configuration for this plugin under lock.
 func (p *HelpPlugin) OnConfigurationChange() error {
-	// Reuse the default implementation of OnConfigurationChange to automatically load the
-	// required TeamName and ChannelName.
-	if err := p.MattermostPlugin.OnConfigurationChange(); err != nil {
-		p.API.LogError(err.Error())
-		return nil
+	var configuration = new(configuration)
+
+	// Load the public configuration fields from the Mattermost server configuration.
+	if err := p.API.LoadPluginConfiguration(configuration); err != nil {
+		return errors.Wrap(err, "failed to load plugin configuration")
 	}
 
-	team, err := p.API.GetTeamByName(p.TeamName)
+	team, err := p.API.GetTeamByName(configuration.TeamName)
 	if err != nil {
-		p.API.LogError("failed to find team", "team_name", p.TeamName)
-		return nil
+		return errors.Wrapf(err, "failed to find team %s", configuration.TeamName)
 	}
 
-	channel, err := p.API.GetChannelByName(p.ChannelName, team.Id, false)
+	channel, err := p.API.GetChannelByName(configuration.ChannelName, team.Id, false)
 	if err != nil {
-		p.API.LogError("failed to find channel", "channel_name", p.ChannelName)
-		return nil
+		return errors.Wrapf(err, "failed to find channel %s", configuration.ChannelName)
 	}
 
-	p.channelId = channel.Id
+	configuration.channelId = channel.Id
+
+	p.setConfiguration(configuration)
 
 	return nil
 }
 
 func (p *HelpPlugin) MessageHasBeenPosted(c *plugin.Context, post *model.Post) {
+	configuration := p.getConfiguration()
+
 	// Ignore posts not in the configured channel
-	if post.ChannelId != p.channelId {
+	if post.ChannelId != configuration.channelId {
 		return
 	}
 
@@ -58,7 +101,7 @@ func (p *HelpPlugin) MessageHasBeenPosted(c *plugin.Context, post *model.Post) {
 	}
 
 	p.API.SendEphemeralPost(post.UserId, &model.Post{
-		ChannelId: p.channelId,
+		ChannelId: configuration.channelId,
 		Message:   "You asked for help? Checkout https://about.mattermost.com/help/",
 		Props: map[string]interface{}{
 			"sent_by_plugin": true,