isle/go-workspace/src/bootstrap/bootstrap.go

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// Package bootstrap deals with the creation of bootstrap files
package bootstrap
import (
"cryptic-net/garage"
"cryptic-net/tarutil"
"cryptic-net/yamlutil"
"crypto/sha512"
"fmt"
"io"
"io/fs"
"os"
"path/filepath"
"sort"
"strings"
"gopkg.in/yaml.v3"
)
// Paths within the bootstrap FS which for general data.
const (
hostNamePath = "hostname"
)
// Bootstrap is used for accessing all information contained within a
// bootstrap.tgz file.
//
// An instance of Bootstrap is read-only, the creator sub-package should be used
// to create new instances.
type Bootstrap struct {
Hosts map[string]Host
HostName string
NebulaCertsCACert string
NebulaCertsHostCert string
NebulaCertsHostKey string
GarageRPCSecret string
GarageGlobalBucketS3APICredentials garage.S3APICredentials
}
// FromFS loads a Boostrap instance from the given fs.FS, which presumably
// represents the file structure of a bootstrap.tgz file.
func FromFS(bootstrapFS fs.FS) (Bootstrap, error) {
var (
b Bootstrap
err error
)
if b.Hosts, err = loadHosts(bootstrapFS); err != nil {
return Bootstrap{}, fmt.Errorf("loading hosts info from fs: %w", err)
}
if err = yamlutil.LoadYamlFSFile(
&b.GarageGlobalBucketS3APICredentials,
bootstrapFS,
garageGlobalBucketKeyYmlPath,
); err != nil {
return Bootstrap{}, fmt.Errorf("loading %q from fs: %w", b.GarageGlobalBucketS3APICredentials, err)
}
filesToLoadAsString := []struct {
into *string
path string
}{
{&b.HostName, hostNamePath},
{&b.NebulaCertsCACert, nebulaCertsCACertPath},
{&b.NebulaCertsHostCert, nebulaCertsHostCertPath},
{&b.NebulaCertsHostKey, nebulaCertsHostKeyPath},
{&b.GarageRPCSecret, garageRPCSecretPath},
}
for _, f := range filesToLoadAsString {
body, err := fs.ReadFile(bootstrapFS, f.path)
if err != nil {
return Bootstrap{}, fmt.Errorf("loading %q from fs: %w", f.path, err)
}
*f.into = string(body)
}
// TODO confirm if this is necessary
b.GarageRPCSecret = strings.TrimSpace(b.GarageRPCSecret)
return b, nil
}
// FromReader reads a bootstrap.tgz file from the given io.Reader.
func FromReader(r io.Reader) (Bootstrap, error) {
fs, err := tarutil.FSFromReader(r)
if err != nil {
return Bootstrap{}, fmt.Errorf("reading bootstrap.tgz: %w", err)
}
return FromFS(fs)
}
// FromFile reads a bootstrap.tgz from a file at the given path.
func FromFile(path string) (Bootstrap, error) {
f, err := os.Open(path)
if err != nil {
return Bootstrap{}, fmt.Errorf("opening file: %w", err)
}
defer f.Close()
return FromReader(f)
}
// WriteTo writes the Bootstrap as a new bootstrap.tgz to the given io.Writer.
func (b Bootstrap) WriteTo(into io.Writer) error {
w := tarutil.NewTGZWriter(into)
filesToWriteAsString := []struct {
value string
path string
}{
{b.HostName, hostNamePath},
{b.NebulaCertsCACert, nebulaCertsCACertPath},
{b.NebulaCertsHostCert, nebulaCertsHostCertPath},
{b.NebulaCertsHostKey, nebulaCertsHostKeyPath},
{b.GarageRPCSecret, garageRPCSecretPath},
}
for _, f := range filesToWriteAsString {
w.WriteFileBytes(f.path, []byte(f.value))
}
garageGlobalBucketKeyB, err := yaml.Marshal(b.GarageGlobalBucketS3APICredentials)
if err != nil {
return fmt.Errorf("yaml encoding garage global bucket creds: %w", err)
}
w.WriteFileBytes(garageGlobalBucketKeyYmlPath, garageGlobalBucketKeyB)
for _, host := range b.Hosts {
hostB, err := yaml.Marshal(host)
if err != nil {
return fmt.Errorf("yaml encoding host %#v: %w", host, err)
}
path := filepath.Join(hostsDirPath, host.Name+".yml")
w.WriteFileBytes(path, hostB)
}
return w.Close()
}
// ThisHost is a shortcut for b.Hosts[b.HostName], but will panic if the
// HostName isn't found in the Hosts map.
func (b Bootstrap) ThisHost() Host {
host, ok := b.Hosts[b.HostName]
if !ok {
panic(fmt.Sprintf("hostname %q not defined in bootstrap's hosts", b.HostName))
}
return host
}
// Hash returns a deterministic hash of the given hosts map.
func HostsHash(hostsMap map[string]Host) ([]byte, error) {
hosts := make([]Host, 0, len(hostsMap))
for _, host := range hostsMap {
hosts = append(hosts, host)
}
sort.Slice(hosts, func(i, j int) bool { return hosts[i].Name < hosts[j].Name })
h := sha512.New()
if err := yaml.NewEncoder(h).Encode(hosts); err != nil {
return nil, err
}
return h.Sum(nil), nil
}
// WithHosts returns a copy of the Bootstrap with the given set of Hosts applied
// to it. It will _not_ overwrite the Host for _this_ host, however.
func (b Bootstrap) WithHosts(hosts map[string]Host) Bootstrap {
hostsCopy := make(map[string]Host, len(hosts))
for name, host := range hosts {
hostsCopy[name] = host
}
hostsCopy[b.HostName] = b.ThisHost()
b.Hosts = hostsCopy
return b
}