Handle potential race during conversation close (#4)

* Avoid race while closing conversation

* Document bot env variables

BOT-WRITING-GUIDE.md

@@ -43,6 +43,18 @@ See the [sample config file](examples/sample-config.yaml) for details on all
 available options and defaults. The config files for the [examples](examples)
 also illustrate most common config options.
 
+## Environment variables
+
+The bot will have access to the following environment variables:
+
+* `BOTTERS_USER_ID`: ID of the bot user account; normally used to identify messages which mention the bot
+* `BOTTERS_USER_NAME` User name of the bot user account
+* `BOTTERS_CHANNEL`: Name of the channel this bot instance is running in
+* `BOTTERS_CHANNEL_ID`: ID of the channel this bot instance is running in
+* `BOTTERS_LOCALE`: Locale of the channel the bot is running in
+
+See [gptbot](examples/gptbot/gptbot.py) for an example of how a bot might use these variables.
+
 ## Botters commands
 
 Botters uses a `botters://` URL scheme for commands. A bot can include these
@@ -66,7 +78,7 @@ following commands are supported currently:
     message. The follow-up message will automatically create the thread in
     Slack.
 
-For example on using Botters commands, see [gamebot](examples/gamebot).
+For an example on using Botters commands, see [gamebot](examples/gamebot).
 
 ## Things to keep in mind
 

conversation/conversation.go

@@ -27,6 +27,9 @@ type Conversation struct {
 	engineQueues       engine.EngineQueues
 	prefixUsername     bool
 	directMessagesOnly bool
+
+	// Flag to indicate that the conversation is closing
+	convClosing bool
 }
 
 func (c *Conversation) Start(ctx context.Context) {
@@ -62,6 +65,7 @@ func (c *Conversation) LaunchEngine(ctx context.Context) {
 	defer cancel()
 	defer func() {
 		logrus.Debug("Closing engine queues")
+		c.convClosing = true
 		close(c.engineQueues.ReadQ)
 		close(c.engineQueues.WriteQ)
 	}()
@@ -125,6 +129,10 @@ func (c *Conversation) LaunchEngine(ctx context.Context) {
 }
 
 func (c *Conversation) Post(m *message.Message) {
+	if c.convClosing {
+		logrus.Debug("Conversation is closing, not posting message: %#v: %s", c, m.Text)
+		return
+	}
 	msg := m.Text
 	if c.prefixUsername {
 		msg = m.User + ": " + msg

conversation/manager.go

@@ -328,6 +328,8 @@ func (cm *Manager) GetConversations(ctx context.Context, m *message.Message) []*
 	}
 	cm.triggerLock.RUnlock()
 
+	logrus.Debugf("Found %d conversations for message %s", len(conversations), m.Text)
+
 	return conversations
 }