Add immutable remote commit reader

This commit is contained in:
2026-08-10 19:47:12 +00:00
parent ee747243fe
commit d6deccf3e8
14 changed files with 914 additions and 98 deletions

View File

@@ -0,0 +1,187 @@
package artifacts
import (
"context"
"fmt"
"os"
"strings"
"gitea.maximumdirect.net/eric/narratio/internal/adapters/storage"
"gitea.maximumdirect.net/eric/narratio/internal/manifest"
)
func loadCommittedCurrentState(
ctx context.Context,
store storage.ObjectStore,
sessionPrefix string,
pointerKey string,
validation CurrentStateValidation,
) (*CurrentState, error) {
pointerData, err := downloadRemoteObject(ctx, store, pointerKey, "narratio-current-commit-pointer-*.json")
if err != nil {
return nil, fmt.Errorf("download current commit pointer %q: %w", pointerKey, err)
}
pointer, err := DecodeCurrentCommitPointer(pointerData)
if err != nil {
return nil, err
}
if err := pointer.ValidateForSessionPrefix(sessionPrefix); err != nil {
return nil, err
}
commitData, err := readVerifiedRemoteObject(ctx, store, pointer.CommitKey, pointer.CommitSHA256, pointer.CommitSize, pointer.CommitGeneration, "narratio-remote-commit-*.json")
if err != nil {
return nil, fmt.Errorf("read selected remote commit %q: %w", pointer.CommitKey, err)
}
commit, err := DecodeRemoteCommitManifest(commitData)
if err != nil {
return nil, err
}
if err := commit.ValidateForSessionPrefix(sessionPrefix); err != nil {
return nil, err
}
if err := validatePointerCommitIdentity(pointer, commit); err != nil {
return nil, err
}
sessionManifest, ok := commit.Artifact(RemoteArtifactTypeSessionManifest)
if !ok {
return nil, fmt.Errorf("remote commit must declare exactly one session manifest artifact")
}
manifestData, err := readVerifiedRemoteObject(ctx, store, sessionManifest.DestinationKey, sessionManifest.SHA256, sessionManifest.Size, sessionManifest.Generation, "narratio-remote-session-manifest-*.json")
if err != nil {
return nil, fmt.Errorf("read committed session manifest %q: %w", sessionManifest.DestinationKey, err)
}
m, err := decodeCommittedManifest(ctx, manifestData)
if err != nil {
return nil, err
}
if err := validateCommitManifestIdentity(commit, m); err != nil {
return nil, err
}
state := &CurrentState{
SessionPrefix: sessionPrefix,
CurrentRunIDKey: pointerKey,
CurrentPointerKey: pointerKey,
CurrentManifestKey: sessionManifest.DestinationKey,
RunID: commit.RunID,
Manifest: m,
Commit: commit,
Pointer: pointer,
}
if err := ValidateCurrentStateIdentity(state, validation); err != nil {
return nil, err
}
return state, nil
}
func validatePointerCommitIdentity(pointer *CurrentCommitPointer, commit *RemoteCommitManifest) error {
if pointer == nil || commit == nil {
return fmt.Errorf("current commit pointer and remote commit are required")
}
if pointer.Campaign != commit.Campaign || pointer.SessionID != commit.SessionID || pointer.RunID != commit.RunID {
return fmt.Errorf("current commit pointer identity does not match selected remote commit")
}
return nil
}
func validateCommitManifestIdentity(commit *RemoteCommitManifest, m *manifest.Manifest) error {
if commit == nil || m == nil {
return fmt.Errorf("remote commit and committed session manifest are required")
}
if commit.Campaign != strings.TrimSpace(m.Campaign) ||
commit.SessionID != strings.TrimSpace(m.SessionID) ||
commit.RunID != strings.TrimSpace(m.RunID) {
return fmt.Errorf("selected remote commit identity does not match committed session manifest")
}
return nil
}
func readVerifiedRemoteObject(
ctx context.Context,
store storage.ObjectStore,
key string,
wantSHA256 string,
wantSize int64,
wantGeneration string,
tempPattern string,
) ([]byte, error) {
data, err := downloadRemoteObject(ctx, store, key, tempPattern)
if err != nil {
return nil, err
}
if int64(len(data)) != wantSize {
return nil, fmt.Errorf("size mismatch: got %d, want %d", len(data), wantSize)
}
if checksum := remoteObjectSHA256(data); checksum != wantSHA256 {
return nil, fmt.Errorf("checksum mismatch: got %s, want %s", checksum, wantSHA256)
}
info, err := remoteObjectInfo(ctx, store, key)
if err != nil {
return nil, err
}
if info.Size != wantSize {
return nil, fmt.Errorf("storage size mismatch: got %d, want %d", info.Size, wantSize)
}
if strings.TrimSpace(info.ETag) != wantGeneration {
return nil, fmt.Errorf("generation mismatch: got %q, want %q", info.ETag, wantGeneration)
}
return data, nil
}
func downloadRemoteObject(ctx context.Context, store storage.ObjectStore, key, tempPattern string) ([]byte, error) {
localPath, err := storage.DownloadObjectToTemp(ctx, store, key, tempPattern)
if err != nil {
return nil, err
}
defer func() { _ = os.Remove(localPath) }()
data, err := os.ReadFile(localPath)
if err != nil {
return nil, fmt.Errorf("read downloaded object %q: %w", key, err)
}
return data, nil
}
func remoteObjectInfo(ctx context.Context, store storage.ObjectStore, key string) (storage.ObjectInfo, error) {
objects, err := store.List(ctx, key)
if err != nil {
return storage.ObjectInfo{}, fmt.Errorf("list remote object %q: %w", key, err)
}
var found *storage.ObjectInfo
for _, object := range objects {
if object.Key != key {
continue
}
if found != nil {
return storage.ObjectInfo{}, fmt.Errorf("remote object %q is ambiguous", key)
}
copy := object
found = &copy
}
if found == nil {
return storage.ObjectInfo{}, fmt.Errorf("remote object %q is missing", key)
}
return *found, nil
}
func decodeCommittedManifest(ctx context.Context, data []byte) (*manifest.Manifest, error) {
file, err := os.CreateTemp("", "narratio-committed-session-manifest-*.json")
if err != nil {
return nil, fmt.Errorf("create committed manifest file: %w", err)
}
path := file.Name()
defer func() { _ = os.Remove(path) }()
if _, err := file.Write(data); err != nil {
_ = file.Close()
return nil, fmt.Errorf("write committed manifest file: %w", err)
}
if err := file.Close(); err != nil {
return nil, fmt.Errorf("close committed manifest file: %w", err)
}
m, err := (&manifest.LocalStore{}).Load(ctx, path)
if err != nil {
return nil, fmt.Errorf("committed session manifest decode failed: %w", err)
}
return m, nil
}