~pedronis/snappy-hub/assert-fetcher

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// -*- Mode: Go; indent-tabs-mode: t -*-

/*
 * Copyright (C) 2017 Canonical Ltd
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 3 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

package main

import (
	"fmt"
	"os"
	"path/filepath"
	"strings"

	"github.com/snapcore/snapd/asserts"
	"github.com/snapcore/snapd/asserts/snapasserts"
	"github.com/snapcore/snapd/asserts/sysdb"
	"github.com/snapcore/snapd/image"
)

func fetchSnapAssertions(tsto *image.ToolingStore, snapPath string) error {
	db, err := asserts.OpenDatabase(&asserts.DatabaseConfig{
		Backstore: asserts.NewMemoryBackstore(),
		Trusted:   sysdb.Trusted(),
	})
	if err != nil {
		return err
	}

	assertPath := strings.TrimSuffix(snapPath, filepath.Ext(snapPath)) + ".assert"
	w, err := os.Create(assertPath)
	if err != nil {
		return fmt.Errorf("cannot create assertions file: %v", err)
	}
	defer w.Close()

	encoder := asserts.NewEncoder(w)
	save := func(a asserts.Assertion) error {
		return encoder.Encode(a)
	}
	f := tsto.AssertionFetcher(db, save)

	sha3_384, _, err := asserts.SnapFileSHA3_384(snapPath)
	if err != nil {
		return err
	}

	// this assumes series "16"
	return snapasserts.FetchSnapAssertions(f, sha3_384)
}

func main() {
	tsto, err := image.NewToolingStore()
	if err != nil {
		fmt.Fprintf(os.Stderr, "%v\n", err)
		os.Exit(1)
	}
	if len(os.Args) < 2 {
		fmt.Fprintf(os.Stderr, "must give a snap\n")
		os.Exit(1)
	}
	snapPath := os.Args[1]

	fmt.Fprintf(os.Stderr, "Fetching assertions for %q\n", snapPath)
	err = fetchSnapAssertions(tsto, snapPath)
	if err != nil {
		fmt.Fprintf(os.Stderr, "cannot fetch assertions: %v\n", err)
		os.Exit(1)
	}
}