fn-registry agent
80 lines
1.9 KiB
Go
80 lines
1.9 KiB
Go
package main
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import (
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"bytes"
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"context"
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"encoding/json"
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"os"
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"os/exec"
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"github.com/mark3labs/mcp-go/mcp"
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)
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type runArgs struct {
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ID string `json:"id"`
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Args []string `json:"args,omitempty"`
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}
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func runTool() mcp.Tool {
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return mcp.NewTool("fn_run",
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mcp.WithDescription("Execute a registry function/pipeline via `fn run <id> [args...]`. Dispatches by language: Go (go run/test), Python (.venv), Bash, TypeScript (tsx). Mutating side-effects possible. Off by default — server must be launched with --enable-run."),
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mcp.WithString("id",
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mcp.Required(),
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mcp.Description("Registry ID or function name."),
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),
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mcp.WithArray("args",
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mcp.Description("Positional args appended to fn run."),
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mcp.Items(map[string]any{"type": "string"}),
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),
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)
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}
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func (d *deps) handleRun(ctx context.Context, _ mcp.CallToolRequest, args runArgs) (*mcp.CallToolResult, error) {
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if args.ID == "" {
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return mcp.NewToolResultError("id is required"), nil
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}
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bin := d.fnBin()
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cmdArgs := append([]string{"run", args.ID}, args.Args...)
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cmd := exec.CommandContext(ctx, bin, cmdArgs...)
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cmd.Dir = d.root
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cmd.Env = os.Environ()
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var stdout, stderr bytes.Buffer
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cmd.Stdout = &stdout
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cmd.Stderr = &stderr
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runErr := cmd.Run()
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exit := 0
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if cmd.ProcessState != nil {
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exit = cmd.ProcessState.ExitCode()
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}
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out := map[string]any{
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"id": args.ID,
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"args": args.Args,
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"exit_code": exit,
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"stdout": truncate(stdout.String(), 100_000),
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"stderr": truncate(stderr.String(), 100_000),
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}
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if runErr != nil && exit == 0 {
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out["error"] = runErr.Error()
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}
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b, _ := json.MarshalIndent(out, "", " ")
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return mcp.NewToolResultText(string(b)), nil
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}
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func (d *deps) fnBin() string {
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if v := os.Getenv("FN_BIN"); v != "" {
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return v
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}
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candidate := d.root + "/fn"
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if _, err := os.Stat(candidate); err == nil {
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return candidate
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}
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if path, err := exec.LookPath("fn"); err == nil {
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return path
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}
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return "fn"
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}
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