vertexai: add NewUserContent helper function (#10570)

vertexai/genai/caching_test.go

@@ -103,9 +103,9 @@ func testCaching(t *testing.T, client *Client) {
 		argcc := &CachedContent{
 			Model:      model,
 			Expiration: ExpireTimeOrTTL{TTL: ttl},
-			Contents: []*Content{{Role: "user", Parts: []Part{
-				FileData{MIMEType: "text/plain", FileURI: gcsFilePath},
-			}}},
+			Contents: []*Content{NewUserContent(FileData{
+				MIMEType: "text/plain",
+				FileURI:  gcsFilePath})},
 		}
 		cc := must(client.CreateCachedContent(ctx, argcc))
 		compare(cc, wantExpireTime)

vertexai/genai/chat.go

@@ -32,7 +32,7 @@ func (m *GenerativeModel) StartChat() *ChatSession {
 // SendMessage sends a request to the model as part of a chat session.
 func (cs *ChatSession) SendMessage(ctx context.Context, parts ...Part) (*GenerateContentResponse, error) {
 	// Call the underlying client with the entire history plus the argument Content.
-	cs.History = append(cs.History, newUserContent(parts))
+	cs.History = append(cs.History, NewUserContent(parts...))
 	req := cs.m.newGenerateContentRequest(cs.History...)
 	cc := int32(1)
 	req.GenerationConfig.CandidateCount = &cc
@@ -46,7 +46,7 @@ func (cs *ChatSession) SendMessage(ctx context.Context, parts ...Part) (*Generat
 
 // SendMessageStream is like SendMessage, but with a streaming request.
 func (cs *ChatSession) SendMessageStream(ctx context.Context, parts ...Part) *GenerateContentResponseIterator {
-	cs.History = append(cs.History, newUserContent(parts))
+	cs.History = append(cs.History, NewUserContent(parts...))
 	req := cs.m.newGenerateContentRequest(cs.History...)
 	var cc int32 = 1
 	req.GenerationConfig.CandidateCount = &cc

vertexai/genai/client.go

@@ -187,12 +187,12 @@ func (m *GenerativeModel) Name() string {
 
 // GenerateContent produces a single request and response.
 func (m *GenerativeModel) GenerateContent(ctx context.Context, parts ...Part) (*GenerateContentResponse, error) {
-	return m.generateContent(ctx, m.newGenerateContentRequest(newUserContent(parts)))
+	return m.generateContent(ctx, m.newGenerateContentRequest(NewUserContent(parts...)))
 }
 
 // GenerateContentStream returns an iterator that enumerates responses.
 func (m *GenerativeModel) GenerateContentStream(ctx context.Context, parts ...Part) *GenerateContentResponseIterator {
-	streamClient, err := m.c.pc.StreamGenerateContent(ctx, m.newGenerateContentRequest(newUserContent(parts)))
+	streamClient, err := m.c.pc.StreamGenerateContent(ctx, m.newGenerateContentRequest(NewUserContent(parts...)))
 	return &GenerateContentResponseIterator{
 		sc:  streamClient,
 		err: err,
@@ -221,10 +221,6 @@ func (m *GenerativeModel) newGenerateContentRequest(contents ...*Content) *pb.Ge
 	}
 }
 
-func newUserContent(parts []Part) *Content {
-	return &Content{Role: roleUser, Parts: parts}
-}
-
 // GenerateContentResponseIterator is an iterator over GnerateContentResponse.
 type GenerateContentResponseIterator struct {
 	sc     pb.PredictionService_StreamGenerateContentClient
@@ -286,7 +282,7 @@ func protoToResponse(resp *pb.GenerateContentResponse) (*GenerateContentResponse
 
 // CountTokens counts the number of tokens in the content.
 func (m *GenerativeModel) CountTokens(ctx context.Context, parts ...Part) (*CountTokensResponse, error) {
-	req := m.newCountTokensRequest(newUserContent(parts))
+	req := m.newCountTokensRequest(NewUserContent(parts...))
 	res, err := m.c.pc.CountTokens(ctx, req)
 	if err != nil {
 		return nil, err

vertexai/genai/client_test.go

@@ -63,9 +63,7 @@ func TestLive(t *testing.T) {
 	t.Run("system-instructions", func(t *testing.T) {
 		model := client.GenerativeModel(defaultModel)
 		model.Temperature = Ptr[float32](0)
-		model.SystemInstruction = &Content{
-			Parts: []Part{Text("You are Yoda from Star Wars.")},
-		}
+		model.SystemInstruction = NewUserContent(Text("You are Yoda from Star Wars."))
 		resp, err := model.GenerateContent(ctx, Text("What is the average size of a swallow?"))
 		if err != nil {
 			t.Fatal(err)

vertexai/genai/content.go

@@ -148,3 +148,13 @@ func (c *Candidate) FunctionCalls() []FunctionCall {
 	}
 	return fcs
 }
+
+// NewUserContent returns a [Content] with a "user" role set and one or more
+// parts.
+func NewUserContent(parts ...Part) *Content {
+	content := &Content{Role: roleUser, Parts: []Part{}}
+	for _, part := range parts {
+		content.Parts = append(content.Parts, part)
+	}
+	return content
+}

vertexai/genai/example_test.go

@@ -74,9 +74,7 @@ func ExampleGenerativeModel_GenerateContent_config() {
 	model.SetTopP(0.5)
 	model.SetTopK(20)
 	model.SetMaxOutputTokens(100)
-	model.SystemInstruction = &genai.Content{
-		Parts: []genai.Part{genai.Text("You are Yoda from Star Wars.")},
-	}
+	model.SystemInstruction = genai.NewUserContent(genai.Text("You are Yoda from Star Wars."))
 	resp, err := model.GenerateContent(ctx, genai.Text("What is the average size of a swallow?"))
 	if err != nil {
 		log.Fatal(err)
@@ -315,7 +313,7 @@ func ExampleClient_cachedContent() {
 	file := genai.FileData{MIMEType: "application/pdf", FileURI: "gs://my-bucket/my-doc.pdf"}
 	cc, err := client.CreateCachedContent(ctx, &genai.CachedContent{
 		Model:    modelName,
-		Contents: []*genai.Content{{Parts: []genai.Part{file}}},
+		Contents: []*genai.Content{genai.NewUserContent(file)},
 	})
 	model := client.GenerativeModelFromCachedContent(cc)
 	// Work with the model as usual in this program.