feat(vertexai): Add function calling basic

vertexai/function-calling/functioncalling.go

@@ -106,7 +106,7 @@ func functionCallsChat(w io.Writer, projectID, location, modelName string) error
 	// with a value for the argument `productName`.
 	jsondata, err := json.MarshalIndent(resp.Candidates[0].Content.Parts[0], "\t", "  ")
 	if err != nil {
-		return fmt.Errorf("json.Marshal: %w", err)
+		return fmt.Errorf("json.MarshalIndent: %w", err)
 	}
 	fmt.Fprintf(w, "function call generated by the model:\n\t%s\n", string(jsondata))
 
@@ -121,7 +121,7 @@ func functionCallsChat(w io.Writer, projectID, location, modelName string) error
 	}
 	jsondata, err = json.MarshalIndent(funresp, "\t", "  ")
 	if err != nil {
-		return fmt.Errorf("json.Marshal: %w", err)
+		return fmt.Errorf("json.MarshalIndent: %w", err)
 	}
 	fmt.Fprintf(w, "function call response sent to the model:\n\t%s\n\n", string(jsondata))
 
@@ -139,7 +139,7 @@ func functionCallsChat(w io.Writer, projectID, location, modelName string) error
 	// reformulated the response to the user.
 	jsondata, err = json.MarshalIndent(resp.Candidates[0].Content.Parts[0], "\t", "  ")
 	if err != nil {
-		return fmt.Errorf("json.Marshal: %w", err)
+		return fmt.Errorf("json.MarshalIndent: %w", err)
 	}
 	fmt.Fprintf(w, "Answer generated by the model:\n\t%s\n\n", string(jsondata))
 
@@ -160,7 +160,7 @@ func functionCallsChat(w io.Writer, projectID, location, modelName string) error
 	// with a value for the argument `store`.
 	jsondata, err = json.MarshalIndent(resp.Candidates[0].Content.Parts[0], "\t", "  ")
 	if err != nil {
-		return fmt.Errorf("json.Marshal: %w", err)
+		return fmt.Errorf("json.MarshalIndent: %w", err)
 	}
 	fmt.Fprintf(w, "function call generated by the model:\n\t%s\n", string(jsondata))
 
@@ -174,7 +174,7 @@ func functionCallsChat(w io.Writer, projectID, location, modelName string) error
 	}
 	jsondata, err = json.MarshalIndent(funresp, "\t", "  ")
 	if err != nil {
-		return fmt.Errorf("json.Marshal: %w", err)
+		return fmt.Errorf("json.MarshalIndent: %w", err)
 	}
 	fmt.Fprintf(w, "function call response sent to the model:\n\t%s\n\n", string(jsondata))
 
@@ -192,7 +192,7 @@ func functionCallsChat(w io.Writer, projectID, location, modelName string) error
 	// reformulated the response to the user.
 	jsondata, err = json.MarshalIndent(resp.Candidates[0].Content.Parts[0], "\t", "  ")
 	if err != nil {
-		return fmt.Errorf("json.Marshal: %w", err)
+		return fmt.Errorf("json.MarshalIndent: %w", err)
 	}
 	fmt.Fprintf(w, "Answer generated by the model:\n\t%s\n\n", string(jsondata))
 	return nil

vertexai/function-calling/functioncalling_basic.go

@@ -0,0 +1,125 @@
+// Copyright 2024 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Function calling lets developers create a description of a function in their code, then pass
+// that description to a language model in a request.
+//
+// This function call example involves 3 messages:
+// - ask the model to generate a function call request
+// - call the Open API service (simulated in this example)
+// - ask the model to interpret the function call response
+package functioncalling
+
+// [START generativeaionvertexai_gemini_function_calling]
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+
+	"cloud.google.com/go/vertexai/genai"
+)
+
+// functionCallsBasic opens a chat session and sends 2 messages to the model:
+// - first, to convert a text into a structured function call request
+// - second, to convert a structured function call response into natural language
+func functionCallsBasic(w io.Writer, prompt, projectID, location, modelName string) error {
+	// prompt := "What's the weather like in Boston?"
+	// location := "us-central1"
+	// modelName := "gemini-1.0-pro-002"
+	ctx := context.Background()
+	client, err := genai.NewClient(ctx, projectID, location)
+	if err != nil {
+		return fmt.Errorf("unable to create client: %w", err)
+	}
+	defer client.Close()
+
+	model := client.GenerativeModel(modelName)
+
+	// Build an OpenAPI schema, in memory
+	params := &genai.Schema{
+		Type: genai.TypeObject,
+		Properties: map[string]*genai.Schema{
+			"location": {
+				Type:        genai.TypeString,
+				Description: "location",
+			},
+		},
+	}
+	fundecl := &genai.FunctionDeclaration{
+		Name:        "getCurrentWeather",
+		Description: "Get the current weather in a given location",
+		Parameters:  params,
+	}
+	model.Tools = []*genai.Tool{
+		{FunctionDeclarations: []*genai.FunctionDeclaration{fundecl}},
+	}
+
+	chat := model.StartChat()
+
+	fmt.Fprintf(w, "Question: %s\n", prompt)
+	resp, err := chat.SendMessage(ctx, genai.Text(prompt))
+	if err != nil {
+		return err
+	}
+	if len(resp.Candidates) == 0 ||
+		len(resp.Candidates[0].Content.Parts) == 0 {
+		return errors.New("empty response from model")
+	}
+
+	// The model has returned a function call to the declared function `getCurrentWeather`
+	// with a value for the argument `location`.
+	jsondata, err := json.MarshalIndent(resp.Candidates[0].Content.Parts[0], "", "  ")
+	if err != nil {
+		return fmt.Errorf("json.MarshalIndent: %w", err)
+	}
+	fmt.Fprintf(w, "function call generated by the model:\n%s\n\n", string(jsondata))
+
+	// Create a function call response, to simulate the result of a call to a
+	// real service
+	funresp := &genai.FunctionResponse{
+		Name: "getCurrentWeather",
+		Response: map[string]any{
+			"currentWeather": "sunny",
+		},
+	}
+	jsondata, err = json.MarshalIndent(funresp, "", "  ")
+	if err != nil {
+		return fmt.Errorf("json.MarshalIndent: %w", err)
+	}
+	fmt.Fprintf(w, "function call response sent to the model:\n%s\n\n", string(jsondata))
+
+	// And provide the function call response to the model
+	resp, err = chat.SendMessage(ctx, funresp)
+	if err != nil {
+		return err
+	}
+	if len(resp.Candidates) == 0 ||
+		len(resp.Candidates[0].Content.Parts) == 0 {
+		return errors.New("empty response from model")
+	}
+
+	// The model has taken the function call response as input, and has
+	// reformulated the response to the user.
+	jsondata, err = json.MarshalIndent(resp.Candidates[0].Content.Parts[0], "", "  ")
+	if err != nil {
+		return fmt.Errorf("json.MarshalIndent: %w", err)
+	}
+	fmt.Fprintf(w, "Answer generated by the model:\n%s\n", string(jsondata))
+
+	return nil
+}
+
+// [END generativeaionvertexai_gemini_function_calling]

vertexai/function-calling/functioncalling_test.go

@@ -21,6 +21,20 @@ import (
 	"github.com/GoogleCloudPlatform/golang-samples/internal/testutil"
 )
 
+func Test_functionCallsBasic(t *testing.T) {
+	tc := testutil.SystemTest(t)
+
+	w := io.Discard
+	prompt := "What's the weather like in Boston?"
+	location := "us-central1"
+	modelName := "gemini-1.0-pro-002"
+
+	err := functionCallsBasic(w, prompt, tc.ProjectID, location, modelName)
+	if err != nil {
+		t.Errorf("Test_functionCalls: %v", err.Error())
+	}
+}
+
 func Test_functionCallsChat(t *testing.T) {
 	tc := testutil.SystemTest(t)