Allow conversations to have "previous messages"

This commit modifies the `Chat` method (in a backwards compatible
way) to allow users to start the conversation with previously
exchanged messages, i.e. messages that had already been exchanged
between the user and the assistant. This practically allows
"loading" previous conversations in order to continue them.

To support this, the `Chat` method now takes `types.Message`
values in a variadic way. The messages field of the `Conversation`
type is also exposed now, so that users may save it.

Author: ido50

libaiac/bedrock/chat.go

@@ -13,19 +13,44 @@ import (
 // Conversation is a struct used to converse with a Bedrock chat model. It
 // maintains all messages sent/received in order to maintain context.
 type Conversation struct {
-	backend  *Bedrock
-	model    string
-	messages []bedrocktypes.Message
+	// Messages is the list of all messages exchanged between the user and the
+	// assistant.
+	Messages []bedrocktypes.Message
+
+	backend *Bedrock
+	model   string
 }
 
 // Chat initiates a conversation with a Bedrock chat model. A conversation
 // maintains context, allowing to send further instructions to modify the output
-// from previous requests.
-func (backend *Bedrock) Chat(model string) types.Conversation {
-	return &Conversation{
+// from previous requests. The name of the model to use must be provided. Users
+// can also supply zero or more "previous messages" that may have been exchanged
+// in the past. This practically allows "loading" previous conversations and
+// continuing them.
+func (backend *Bedrock) Chat(model string, msgs ...types.Message) types.Conversation {
+	chat := &Conversation{
 		backend: backend,
 		model:   model,
 	}
+
+	if len(msgs) > 0 {
+		chat.Messages = make([]bedrocktypes.Message, len(msgs))
+		for i := range msgs {
+			role := bedrocktypes.ConversationRoleUser
+			if msgs[i].Role == "assistant" {
+				role = bedrocktypes.ConversationRoleAssistant
+			}
+
+			chat.Messages[i] = bedrocktypes.Message{
+				Role: role,
+				Content: []bedrocktypes.ContentBlock{
+					&bedrocktypes.ContentBlockMemberText{Value: msgs[i].Content},
+				},
+			}
+		}
+	}
+
+	return chat
 }
 
 // Send sends the provided message to the backend and returns a Response object.
@@ -36,7 +61,7 @@ func (conv *Conversation) Send(ctx context.Context, prompt string) (
 	res types.Response,
 	err error,
 ) {
-	conv.messages = append(conv.messages, bedrocktypes.Message{
+	conv.Messages = append(conv.Messages, bedrocktypes.Message{
 		Role: bedrocktypes.ConversationRoleUser,
 		Content: []bedrocktypes.ContentBlock{
 			&bedrocktypes.ContentBlockMemberText{Value: prompt},
@@ -45,7 +70,7 @@ func (conv *Conversation) Send(ctx context.Context, prompt string) (
 
 	input := bedrockruntime.ConverseInput{
 		ModelId:  aws.String(conv.model),
-		Messages: conv.messages,
+		Messages: conv.Messages,
 		InferenceConfig: &bedrocktypes.InferenceConfiguration{
 			Temperature: aws.Float32(0.2),
 		},
@@ -76,7 +101,7 @@ func (conv *Conversation) Send(ctx context.Context, prompt string) (
 	res.TokensUsed = int64(*output.Usage.TotalTokens)
 	res.StopReason = string(output.StopReason)
 
-	conv.messages = append(conv.messages, outputMsg)
+	conv.Messages = append(conv.Messages, outputMsg)
 
 	if res.Code, ok = types.ExtractCode(res.FullOutput); !ok {
 		res.Code = res.FullOutput

libaiac/ollama/chat.go

@@ -11,9 +11,12 @@ import (
 // Conversation is a struct used to converse with an Ollama chat model. It
 // maintains all messages sent/received in order to maintain context.
 type Conversation struct {
-	backend  *Ollama
-	model    string
-	messages []types.Message
+	// Messages is the list of all messages exchanged between the user and the
+	// assistant.
+	Messages []types.Message
+
+	backend *Ollama
+	model   string
 }
 
 type chatResponse struct {
@@ -23,12 +26,21 @@ type chatResponse struct {
 
 // Chat initiates a conversation with an Ollama chat model. A conversation
 // maintains context, allowing to send further instructions to modify the output
-// from previous requests.
-func (backend *Ollama) Chat(model string) types.Conversation {
-	return &Conversation{
+// from previous requests. The name of the model to use must be provided. Users
+// can also supply zero or more "previous messages" that may have been exchanged
+// in the past. This practically allows "loading" previous conversations and
+// continuing them.
+func (backend *Ollama) Chat(model string, msgs ...types.Message) types.Conversation {
+	chat := &Conversation{
 		backend: backend,
 		model:   model,
 	}
+
+	if len(msgs) > 0 {
+		chat.Messages = msgs
+	}
+
+	return chat
 }
 
 // Send sends the provided message to the API and returns a Response object.
@@ -41,15 +53,15 @@ func (conv *Conversation) Send(ctx context.Context, prompt string) (
 ) {
 	var answer chatResponse
 
-	conv.messages = append(conv.messages, types.Message{
+	conv.Messages = append(conv.Messages, types.Message{
 		Role:    "user",
 		Content: prompt,
 	})
 
 	err = conv.backend.NewRequest("POST", "/chat").
 		JSONBody(map[string]interface{}{
 			"model":    conv.model,
-			"messages": conv.messages,
+			"messages": conv.Messages,
 			"options": map[string]interface{}{
 				"temperature": 0.2,
 			},
@@ -61,7 +73,7 @@ func (conv *Conversation) Send(ctx context.Context, prompt string) (
 		return res, fmt.Errorf("failed sending prompt: %w", err)
 	}
 
-	conv.messages = append(conv.messages, answer.Message)
+	conv.Messages = append(conv.Messages, answer.Message)
 
 	res.FullOutput = strings.TrimSpace(answer.Message.Content)
 	if answer.Done {

libaiac/openai/chat.go

@@ -12,9 +12,12 @@ import (
 // maintains all messages sent/received in order to maintain context just like
 // using ChatGPT.
 type Conversation struct {
-	backend  *OpenAI
-	model    string
-	messages []types.Message
+	// Messages is the list of all messages exchanged between the user and the
+	// assistant.
+	Messages []types.Message
+
+	backend *OpenAI
+	model   string
 }
 
 type chatResponse struct {
@@ -30,12 +33,21 @@ type chatResponse struct {
 
 // Chat initiates a conversation with an OpenAI chat model. A conversation
 // maintains context, allowing to send further instructions to modify the output
-// from previous requests, just like using the ChatGPT website.
-func (backend *OpenAI) Chat(model string) types.Conversation {
-	return &Conversation{
+// from previous requests, just like using the ChatGPT website. The name of the
+// model to use must be provided. Users can also supply zero or more "previous
+// messages" that may have been exchanged in the past. This practically allows
+// "loading" previous conversations and continuing them.
+func (backend *OpenAI) Chat(model string, msgs ...types.Message) types.Conversation {
+	chat := &Conversation{
 		backend: backend,
 		model:   model,
 	}
+
+	if len(msgs) > 0 {
+		chat.Messages = msgs
+	}
+
+	return chat
 }
 
 // Send sends the provided message to the API and returns a Response object.
@@ -48,7 +60,7 @@ func (conv *Conversation) Send(ctx context.Context, prompt string) (
 ) {
 	var answer chatResponse
 
-	conv.messages = append(conv.messages, types.Message{
+	conv.Messages = append(conv.Messages, types.Message{
 		Role:    "user",
 		Content: prompt,
 	})
@@ -62,7 +74,7 @@ func (conv *Conversation) Send(ctx context.Context, prompt string) (
 		NewRequest("POST", fmt.Sprintf("/chat/completions%s", apiVersion)).
 		JSONBody(map[string]interface{}{
 			"model":       conv.model,
-			"messages":    conv.messages,
+			"messages":    conv.Messages,
 			"temperature": 0.2,
 		}).
 		Into(&answer).
@@ -75,7 +87,7 @@ func (conv *Conversation) Send(ctx context.Context, prompt string) (
 		return res, types.ErrNoResults
 	}
 
-	conv.messages = append(conv.messages, answer.Choices[0].Message)
+	conv.Messages = append(conv.Messages, answer.Choices[0].Message)
 
 	res.FullOutput = strings.TrimSpace(answer.Choices[0].Message.Content)
 	res.APIKeyUsed = conv.backend.apiKey

libaiac/types/interfaces.go

@@ -8,8 +8,11 @@ type Backend interface {
 	// ListModels returns a list of all models supported by the backend.
 	ListModels(context.Context) ([]string, error)
 
-	// Chat initiates a conversation with an LLM backend.
-	Chat(string) Conversation
+	// Chat initiates a conversation with an LLM backend. The name of the model
+	// to use must be provided. Users can also supply zero or more "previous
+	// messages" that may have been exchanged in the past. This practically
+	// allows "loading" previous conversations and continuing them.
+	Chat(string, ...Message) Conversation
 }
 
 // Conversation is an interface that must be implemented in order to support