Files
meta-core/internal/snapshot/export.go
T
2026-10-19 20:51:00 +00:00

133 lines
3.9 KiB
Go

package snapshot
import (
"archive/zip"
"encoding/json"
"fmt"
"io"
"log"
"os"
"time"
"github.com/metazla/meta-core/internal/storage"
)
// ExportOptions controls what an export includes.
type ExportOptions struct {
IncludePluginOutput bool
// PluginOutputDir is the absolute path on disk that holds plugin-produced
// artifacts (typically $FILES_PATH/plugin). Required when
// IncludePluginOutput is true.
PluginOutputDir string
// SourceHost is recorded in the manifest so imports can attribute
// where the snapshot came from (defaults to OS hostname).
SourceHost string
}
// Exporter writes snapshot ZIPs from the live metadata store.
type Exporter struct {
storage *storage.Client
}
func NewExporter(stor *storage.Client) *Exporter {
return &Exporter{storage: stor}
}
// Export streams a ZIP archive to w. The archive layout is:
//
// manifest.json
// index.json
// metadata/{cid}.json (one per known CID)
//
// Optional sections (hash-index, plugin-output) are gated by ExportOptions
// but are not yet implemented — they live on filesystems meta-core does not
// own, and need cross-service collection. The flag is plumbed for forward
// compatibility but does nothing today.
func (e *Exporter) Export(w io.Writer, opts ExportOptions) (Manifest, error) {
if e.storage == nil || !e.storage.IsConnected() {
return Manifest{}, fmt.Errorf("storage not connected")
}
hashIDs, err := e.storage.GetAllHashIDs()
if err != nil {
return Manifest{}, fmt.Errorf("list hashIDs: %w", err)
}
zw := zip.NewWriter(w)
defer zw.Close()
// 1. manifest.json — written last after we know FileCount, but we need
// the entry order to put it first in the archive for readers. Solve
// by buffering in memory: it's tiny.
host := opts.SourceHost
if host == "" {
if h, err := os.Hostname(); err == nil {
host = h
}
}
manifest := Manifest{
SchemaVersion: ManifestSchemaVersion,
GeneratedAt: time.Now().UTC(),
SourceHost: host,
FileCount: len(hashIDs),
Includes: Includes{
Metadata: true,
PluginOutput: opts.IncludePluginOutput,
},
}
if err := writeJSON(zw, ManifestFile, manifest); err != nil {
return Manifest{}, fmt.Errorf("write manifest: %w", err)
}
// 2. index.json — flat list of CIDs. Redundant with metadata/ but
// cheap and useful for readers that only need the keyset.
if err := writeJSON(zw, IndexFile, IndexFileBody{HashIDs: hashIDs}); err != nil {
return Manifest{}, fmt.Errorf("write index: %w", err)
}
// 3. metadata/{cid}.json — one nested document per CID.
for _, hashID := range hashIDs {
flat, err := e.storage.GetMetadataFlat(hashID)
if err != nil {
log.Printf("[Snapshot] export: skipping %s: %v", hashID, err)
continue
}
if len(flat) == 0 {
continue
}
nested := Reconstruct(flat)
entry := MetadataDir + hashID + ".json"
if err := writeJSON(zw, entry, nested); err != nil {
return Manifest{}, fmt.Errorf("write %s: %w", entry, err)
}
}
// 4. cache/plugin-output/* — optional. Walks the on-disk plugin dir and
// streams each file into the ZIP. Heavy (~120 MB on a populated dev
// stack), so it's gated by the ExportOptions toggle.
if opts.IncludePluginOutput {
if opts.PluginOutputDir == "" {
return Manifest{}, fmt.Errorf("PluginOutputDir is required when IncludePluginOutput is set")
}
n, err := addPluginOutput(zw, opts.PluginOutputDir)
if err != nil {
return Manifest{}, fmt.Errorf("add plugin-output: %w", err)
}
log.Printf("[Snapshot] exported %d plugin-output files from %s", n, opts.PluginOutputDir)
}
log.Printf("[Snapshot] exported %d files (host=%s, pluginOutput=%v)",
len(hashIDs), host, opts.IncludePluginOutput)
return manifest, nil
}
func writeJSON(zw *zip.Writer, name string, body interface{}) error {
w, err := zw.Create(name)
if err != nil {
return err
}
enc := json.NewEncoder(w)
enc.SetIndent("", " ")
return enc.Encode(body)
}