genai-toolbox/internal/tools/postgres/postgreslistinstalledextensions/postgreslistinstalledextensions.go

// Copyright 2025 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.

package postgreslistinstalledextensions

import (
	"context"
	"fmt"

	yaml "github.com/goccy/go-yaml"
	"github.com/googleapis/genai-toolbox/internal/sources"
	"github.com/googleapis/genai-toolbox/internal/sources/alloydbpg"
	"github.com/googleapis/genai-toolbox/internal/sources/cloudsqlpg"
	"github.com/googleapis/genai-toolbox/internal/sources/postgres"
	"github.com/googleapis/genai-toolbox/internal/tools"
	"github.com/jackc/pgx/v5/pgxpool"
)

const kind string = "postgres-list-installed-extensions"

const listAvailableExtensionsQuery = `
	SELECT
		e.extname AS name,
		e.extversion AS version,
		n.nspname AS schema,
		pg_get_userbyid(e.extowner) AS owner,
		c.description AS description
	FROM
		pg_catalog.pg_extension e
	LEFT JOIN
		pg_catalog.pg_namespace n
	ON
		n.oid = e.extnamespace
	LEFT JOIN
		pg_catalog.pg_description c
	ON
		c.objoid = e.oid
		AND c.classoid = 'pg_catalog.pg_extension'::pg_catalog.regclass
	ORDER BY 1;
`

func init() {
	if !tools.Register(kind, newConfig) {
		panic(fmt.Sprintf("tool kind %q already registered", kind))
	}
}

func newConfig(ctx context.Context, name string, decoder *yaml.Decoder) (tools.ToolConfig, error) {
	actual := Config{Name: name}
	if err := decoder.DecodeContext(ctx, &actual); err != nil {
		return nil, err
	}
	return actual, nil
}

type compatibleSource interface {
	PostgresPool() *pgxpool.Pool
}

// validate compatible sources are still compatible
var _ compatibleSource = &alloydbpg.Source{}
var _ compatibleSource = &cloudsqlpg.Source{}
var _ compatibleSource = &postgres.Source{}

var compatibleSources = [...]string{alloydbpg.SourceKind, cloudsqlpg.SourceKind, postgres.SourceKind}

type Config struct {
	Name         string   `yaml:"name" validate:"required"`
	Kind         string   `yaml:"kind" validate:"required"`
	Source       string   `yaml:"source" validate:"required"`
	Description  string   `yaml:"description" validate:"required"`
	AuthRequired []string `yaml:"authRequired"`
}

// validate interface
var _ tools.ToolConfig = Config{}

func (cfg Config) ToolConfigKind() string {
	return kind
}

func (cfg Config) Initialize(srcs map[string]sources.Source) (tools.Tool, error) {
	// verify source exists
	rawS, ok := srcs[cfg.Source]
	if !ok {
		return nil, fmt.Errorf("no source named %q configured", cfg.Source)
	}

	// verify the source is compatible
	s, ok := rawS.(compatibleSource)
	if !ok {
		return nil, fmt.Errorf("invalid source for %q tool: source kind must be one of %q", kind, compatibleSources)
	}

	parameters := tools.Parameters{}

	mcpManifest := tools.McpManifest{
		Name:        cfg.Name,
		Description: cfg.Description,
		InputSchema: parameters.McpManifest(),
	}

	// finish tool setup
	t := Tool{
		Name:         cfg.Name,
		Kind:         cfg.Kind,
		AuthRequired: cfg.AuthRequired,
		Pool:         s.PostgresPool(),
		manifest: tools.Manifest{
			Description:  cfg.Description,
			Parameters:   parameters.Manifest(),
			AuthRequired: cfg.AuthRequired,
		},
		mcpManifest: mcpManifest,
	}
	return t, nil
}

// validate interface
var _ tools.Tool = Tool{}

type Tool struct {
	Name         string   `yaml:"name"`
	Kind         string   `yaml:"kind"`
	AuthRequired []string `yaml:"authRequired"`
	Pool         *pgxpool.Pool
	manifest     tools.Manifest
	mcpManifest  tools.McpManifest
}

func (t Tool) Invoke(ctx context.Context, params tools.ParamValues, accessToken tools.AccessToken) (any, error) {
	results, err := t.Pool.Query(ctx, listAvailableExtensionsQuery)
	if err != nil {
		return nil, fmt.Errorf("unable to execute query: %w", err)
	}

	fields := results.FieldDescriptions()

	var out []any
	for results.Next() {
		v, err := results.Values()
		if err != nil {
			return nil, fmt.Errorf("unable to parse row: %w", err)
		}
		vMap := make(map[string]any)
		for i, f := range fields {
			vMap[f.Name] = v[i]
		}
		out = append(out, vMap)
	}

	return out, nil
}

func (t Tool) ParseParams(data map[string]any, claims map[string]map[string]any) (tools.ParamValues, error) {
	return tools.ParamValues{}, nil
}

func (t Tool) Manifest() tools.Manifest {
	return t.manifest
}

func (t Tool) McpManifest() tools.McpManifest {
	return t.mcpManifest
}

func (t Tool) Authorized(verifiedAuthServices []string) bool {
	return tools.IsAuthorized(t.AuthRequired, verifiedAuthServices)
}

func (t Tool) RequiresClientAuthorization() bool {
	return false
}