git-bug/identity/identity.go
2022-03-10 16:30:27 +01:00

621 lines
16 KiB
Go

// Package identity contains the identity data model and low-level related functions
package identity
import (
"encoding/json"
"fmt"
"reflect"
"github.com/pkg/errors"
"github.com/MichaelMure/git-bug/entity"
"github.com/MichaelMure/git-bug/repository"
"github.com/MichaelMure/git-bug/util/lamport"
"github.com/MichaelMure/git-bug/util/timestamp"
)
const identityRefPattern = "refs/identities/"
const identityRemoteRefPattern = "refs/remotes/%s/identities/"
const versionEntryName = "version"
const identityConfigKey = "git-bug.identity"
var ErrNonFastForwardMerge = errors.New("non fast-forward identity merge")
var ErrNoIdentitySet = errors.New("No identity is set.\n" +
"To interact with bugs, an identity first needs to be created using " +
"\"git bug user create\"")
var ErrMultipleIdentitiesSet = errors.New("multiple user identities set")
func NewErrMultipleMatchIdentity(matching []entity.Id) *entity.ErrMultipleMatch {
return entity.NewErrMultipleMatch("identity", matching)
}
var _ Interface = &Identity{}
var _ entity.Interface = &Identity{}
type Identity struct {
// all the successive version of the identity
versions []*version
}
func NewIdentity(repo repository.RepoClock, name string, email string) (*Identity, error) {
return NewIdentityFull(repo, name, email, "", "", nil)
}
func NewIdentityFull(repo repository.RepoClock, name string, email string, login string, avatarUrl string, keys []*Key) (*Identity, error) {
v, err := newVersion(repo, name, email, login, avatarUrl, keys)
if err != nil {
return nil, err
}
return &Identity{
versions: []*version{v},
}, nil
}
// NewFromGitUser will query the repository for user detail and
// build the corresponding Identity
func NewFromGitUser(repo repository.ClockedRepo) (*Identity, error) {
name, err := repo.GetUserName()
if err != nil {
return nil, err
}
if name == "" {
return nil, errors.New("user name is not configured in git yet. Please use `git config --global user.name \"John Doe\"`")
}
email, err := repo.GetUserEmail()
if err != nil {
return nil, err
}
if email == "" {
return nil, errors.New("user name is not configured in git yet. Please use `git config --global user.email johndoe@example.com`")
}
return NewIdentity(repo, name, email)
}
// MarshalJSON will only serialize the id
func (i *Identity) MarshalJSON() ([]byte, error) {
return json.Marshal(&IdentityStub{
id: i.Id(),
})
}
// UnmarshalJSON will only read the id
// Users of this package are expected to run Load() to load
// the remaining data from the identities data in git.
func (i *Identity) UnmarshalJSON(data []byte) error {
panic("identity should be loaded with identity.UnmarshalJSON")
}
// ReadLocal load a local Identity from the identities data available in git
func ReadLocal(repo repository.Repo, id entity.Id) (*Identity, error) {
ref := fmt.Sprintf("%s%s", identityRefPattern, id)
return read(repo, ref)
}
// ReadRemote load a remote Identity from the identities data available in git
func ReadRemote(repo repository.Repo, remote string, id string) (*Identity, error) {
ref := fmt.Sprintf(identityRemoteRefPattern, remote) + id
return read(repo, ref)
}
// read will load and parse an identity from git
func read(repo repository.Repo, ref string) (*Identity, error) {
id := entity.RefToId(ref)
if err := id.Validate(); err != nil {
return nil, errors.Wrap(err, "invalid ref")
}
hashes, err := repo.ListCommits(ref)
if err != nil {
return nil, ErrIdentityNotExist
}
if len(hashes) == 0 {
return nil, fmt.Errorf("empty identity")
}
i := &Identity{}
for _, hash := range hashes {
entries, err := repo.ReadTree(hash)
if err != nil {
return nil, errors.Wrap(err, "can't list git tree entries")
}
if len(entries) != 1 {
return nil, fmt.Errorf("invalid identity data at hash %s", hash)
}
entry := entries[0]
if entry.Name != versionEntryName {
return nil, fmt.Errorf("invalid identity data at hash %s", hash)
}
data, err := repo.ReadData(entry.Hash)
if err != nil {
return nil, errors.Wrap(err, "failed to read git blob data")
}
var version version
err = json.Unmarshal(data, &version)
if err != nil {
return nil, errors.Wrapf(err, "failed to decode Identity version json %s", hash)
}
// tag the version with the commit hash
version.commitHash = hash
i.versions = append(i.versions, &version)
}
if id != i.versions[0].Id() {
return nil, fmt.Errorf("identity ID doesn't math the first version ID")
}
return i, nil
}
// ListLocalIds list all the available local identity ids
func ListLocalIds(repo repository.Repo) ([]entity.Id, error) {
refs, err := repo.ListRefs(identityRefPattern)
if err != nil {
return nil, err
}
return entity.RefsToIds(refs), nil
}
// RemoveIdentity will remove a local identity from its entity.Id
func RemoveIdentity(repo repository.ClockedRepo, id entity.Id) error {
var fullMatches []string
refs, err := repo.ListRefs(identityRefPattern + id.String())
if err != nil {
return err
}
if len(refs) > 1 {
return NewErrMultipleMatchIdentity(entity.RefsToIds(refs))
}
if len(refs) == 1 {
// we have the identity locally
fullMatches = append(fullMatches, refs[0])
}
remotes, err := repo.GetRemotes()
if err != nil {
return err
}
for remote := range remotes {
remotePrefix := fmt.Sprintf(identityRemoteRefPattern+id.String(), remote)
remoteRefs, err := repo.ListRefs(remotePrefix)
if err != nil {
return err
}
if len(remoteRefs) > 1 {
return NewErrMultipleMatchIdentity(entity.RefsToIds(refs))
}
if len(remoteRefs) == 1 {
// found the identity in a remote
fullMatches = append(fullMatches, remoteRefs[0])
}
}
if len(fullMatches) == 0 {
return ErrIdentityNotExist
}
for _, ref := range fullMatches {
err = repo.RemoveRef(ref)
if err != nil {
return err
}
}
return nil
}
type StreamedIdentity struct {
Identity *Identity
Err error
}
// ReadAllLocal read and parse all local Identity
func ReadAllLocal(repo repository.ClockedRepo) <-chan StreamedIdentity {
return readAll(repo, identityRefPattern)
}
// ReadAllRemote read and parse all remote Identity for a given remote
func ReadAllRemote(repo repository.ClockedRepo, remote string) <-chan StreamedIdentity {
refPrefix := fmt.Sprintf(identityRemoteRefPattern, remote)
return readAll(repo, refPrefix)
}
// readAll read and parse all available bug with a given ref prefix
func readAll(repo repository.ClockedRepo, refPrefix string) <-chan StreamedIdentity {
out := make(chan StreamedIdentity)
go func() {
defer close(out)
refs, err := repo.ListRefs(refPrefix)
if err != nil {
out <- StreamedIdentity{Err: err}
return
}
for _, ref := range refs {
b, err := read(repo, ref)
if err != nil {
out <- StreamedIdentity{Err: err}
return
}
out <- StreamedIdentity{Identity: b}
}
}()
return out
}
type Mutator struct {
Name string
Login string
Email string
AvatarUrl string
Keys []*Key
}
// Mutate allow to create a new version of the Identity in one go
func (i *Identity) Mutate(repo repository.RepoClock, f func(orig *Mutator)) error {
copyKeys := func(keys []*Key) []*Key {
result := make([]*Key, len(keys))
for i, key := range keys {
result[i] = key.Clone()
}
return result
}
orig := Mutator{
Name: i.Name(),
Email: i.Email(),
Login: i.Login(),
AvatarUrl: i.AvatarUrl(),
Keys: copyKeys(i.Keys()),
}
mutated := orig
mutated.Keys = copyKeys(orig.Keys)
f(&mutated)
if reflect.DeepEqual(orig, mutated) {
return nil
}
v, err := newVersion(repo,
mutated.Name,
mutated.Email,
mutated.Login,
mutated.AvatarUrl,
mutated.Keys,
)
if err != nil {
return err
}
i.versions = append(i.versions, v)
return nil
}
// Write the identity into the Repository. In particular, this ensure that
// the Id is properly set.
func (i *Identity) Commit(repo repository.ClockedRepo) error {
if !i.NeedCommit() {
return fmt.Errorf("can't commit an identity with no pending version")
}
if err := i.Validate(); err != nil {
return errors.Wrap(err, "can't commit an identity with invalid data")
}
var lastCommit repository.Hash
for _, v := range i.versions {
if v.commitHash != "" {
lastCommit = v.commitHash
// ignore already commit versions
continue
}
blobHash, err := v.Write(repo)
if err != nil {
return err
}
// Make a git tree referencing the blob
tree := []repository.TreeEntry{
{ObjectType: repository.Blob, Hash: blobHash, Name: versionEntryName},
}
treeHash, err := repo.StoreTree(tree)
if err != nil {
return err
}
var commitHash repository.Hash
if lastCommit != "" {
commitHash, err = repo.StoreCommit(treeHash, lastCommit)
} else {
commitHash, err = repo.StoreCommit(treeHash)
}
if err != nil {
return err
}
lastCommit = commitHash
v.commitHash = commitHash
}
ref := fmt.Sprintf("%s%s", identityRefPattern, i.Id().String())
return repo.UpdateRef(ref, lastCommit)
}
func (i *Identity) CommitAsNeeded(repo repository.ClockedRepo) error {
if !i.NeedCommit() {
return nil
}
return i.Commit(repo)
}
func (i *Identity) NeedCommit() bool {
for _, v := range i.versions {
if v.commitHash == "" {
return true
}
}
return false
}
// Merge will merge a different version of the same Identity
//
// To make sure that an Identity history can't be altered, a strict fast-forward
// only policy is applied here. As an Identity should be tied to a single user, this
// should work in practice, but it does leave a possibility that a user would edit his
// Identity from two different repo concurrently and push the changes in a non-centralized
// network of repositories. In this case, it would result in some repo accepting one
// version and some other accepting another, preventing the network in general to converge
// to the same result. This would create a sort of partition of the network, and manual
// cleaning would be required.
//
// An alternative approach would be to have a determinist rebase:
// - any commits present in both local and remote version would be kept, never changed.
// - newer commits would be merged in a linear chain of commits, ordered based on the
// Lamport time
//
// However, this approach leave the possibility, in the case of a compromised crypto keys,
// of forging a new version with a bogus Lamport time to be inserted before a legit version,
// invalidating the correct version and hijacking the Identity. There would only be a short
// period of time when this would be possible (before the network converge) but I'm not
// confident enough to implement that. I choose the strict fast-forward only approach,
// despite its potential problem with two different version as mentioned above.
func (i *Identity) Merge(repo repository.Repo, other *Identity) (bool, error) {
if i.Id() != other.Id() {
return false, errors.New("merging unrelated identities is not supported")
}
modified := false
var lastCommit repository.Hash
for j, otherVersion := range other.versions {
// if there is more version in other, take them
if len(i.versions) == j {
i.versions = append(i.versions, otherVersion)
lastCommit = otherVersion.commitHash
modified = true
}
// we have a non fast-forward merge.
// as explained in the doc above, refusing to merge
if i.versions[j].commitHash != otherVersion.commitHash {
return false, ErrNonFastForwardMerge
}
}
if modified {
err := repo.UpdateRef(identityRefPattern+i.Id().String(), lastCommit)
if err != nil {
return false, err
}
}
return false, nil
}
// Validate check if the Identity data is valid
func (i *Identity) Validate() error {
lastTimes := make(map[string]lamport.Time)
if len(i.versions) == 0 {
return fmt.Errorf("no version")
}
for _, v := range i.versions {
if err := v.Validate(); err != nil {
return err
}
// check for always increasing lamport time
// check that a new version didn't drop a clock
for name, previous := range lastTimes {
if now, ok := v.times[name]; ok {
if now < previous {
return fmt.Errorf("non-chronological lamport clock %s (%d --> %d)", name, previous, now)
}
} else {
return fmt.Errorf("version has less lamport clocks than before (missing %s)", name)
}
}
for name, now := range v.times {
lastTimes[name] = now
}
}
return nil
}
func (i *Identity) lastVersion() *version {
if len(i.versions) <= 0 {
panic("no version at all")
}
return i.versions[len(i.versions)-1]
}
// Id return the Identity identifier
func (i *Identity) Id() entity.Id {
// id is the id of the first version
return i.versions[0].Id()
}
// Name return the last version of the name
func (i *Identity) Name() string {
return i.lastVersion().name
}
// DisplayName return a non-empty string to display, representing the
// identity, based on the non-empty values.
func (i *Identity) DisplayName() string {
switch {
case i.Name() == "" && i.Login() != "":
return i.Login()
case i.Name() != "" && i.Login() == "":
return i.Name()
case i.Name() != "" && i.Login() != "":
return fmt.Sprintf("%s (%s)", i.Name(), i.Login())
}
panic("invalid person data")
}
// Email return the last version of the email
func (i *Identity) Email() string {
return i.lastVersion().email
}
// Login return the last version of the login
func (i *Identity) Login() string {
return i.lastVersion().login
}
// AvatarUrl return the last version of the Avatar URL
func (i *Identity) AvatarUrl() string {
return i.lastVersion().avatarURL
}
// Keys return the last version of the valid keys
func (i *Identity) Keys() []*Key {
return i.lastVersion().keys
}
// SigningKey return the key that should be used to sign new messages. If no key is available, return nil.
func (i *Identity) SigningKey(repo repository.RepoKeyring) (*Key, error) {
keys := i.Keys()
for _, key := range keys {
err := key.ensurePrivateKey(repo)
if err == errNoPrivateKey {
continue
}
if err != nil {
return nil, err
}
return key, nil
}
return nil, nil
}
// ValidKeysAtTime return the set of keys valid at a given lamport time
func (i *Identity) ValidKeysAtTime(clockName string, time lamport.Time) []*Key {
var result []*Key
var lastTime lamport.Time
for _, v := range i.versions {
refTime, ok := v.times[clockName]
if !ok {
refTime = lastTime
}
lastTime = refTime
if refTime > time {
return result
}
result = v.keys
}
return result
}
// LastModification return the timestamp at which the last version of the identity became valid.
func (i *Identity) LastModification() timestamp.Timestamp {
return timestamp.Timestamp(i.lastVersion().unixTime)
}
// LastModificationLamports return the lamport times at which the last version of the identity became valid.
func (i *Identity) LastModificationLamports() map[string]lamport.Time {
return i.lastVersion().times
}
// IsProtected return true if the chain of git commits started to be signed.
// If that's the case, only signed commit with a valid key for this identity can be added.
func (i *Identity) IsProtected() bool {
// Todo
return false
}
// SetMetadata store arbitrary metadata along the last not-commit version.
// If the version has been commit to git already, a new identical version is added and will need to be
// commit.
func (i *Identity) SetMetadata(key string, value string) {
// once commit, data is immutable so we create a new version
if i.lastVersion().commitHash != "" {
i.versions = append(i.versions, i.lastVersion().Clone())
}
// if Id() has been called, we can't change the first version anymore, so we create a new version
if len(i.versions) == 1 && i.versions[0].id != entity.UnsetId && i.versions[0].id != "" {
i.versions = append(i.versions, i.lastVersion().Clone())
}
i.lastVersion().SetMetadata(key, value)
}
// ImmutableMetadata return all metadata for this Identity, accumulated from each version.
// If multiple value are found, the first defined takes precedence.
func (i *Identity) ImmutableMetadata() map[string]string {
metadata := make(map[string]string)
for _, version := range i.versions {
for key, value := range version.metadata {
if _, has := metadata[key]; !has {
metadata[key] = value
}
}
}
return metadata
}
// MutableMetadata return all metadata for this Identity, accumulated from each version.
// If multiple value are found, the last defined takes precedence.
func (i *Identity) MutableMetadata() map[string]string {
metadata := make(map[string]string)
for _, version := range i.versions {
for key, value := range version.metadata {
metadata[key] = value
}
}
return metadata
}