feat: add schema fingerprint and Z10d alter; refresh sync coop docs

Ship ensure ADD COLUMN and fingerprint API for Yuheng reconcile, and rewrite §0.2–0.3 cooperation checklist in the联调意见.

Co-authored-by: Cursor <cursoragent@cursor.com>

platform/internal/dbsync/fingerprint.go

@@ -0,0 +1,199 @@
+package dbsync
+
+import (
+	"context"
+	"crypto/sha256"
+	"database/sql"
+	"encoding/hex"
+	"encoding/json"
+	"fmt"
+	"sort"
+	"strings"
+)
+
+// FingerprintTable 单表指纹（与宇恒 sync_fingerprint 算法对齐）。
+type FingerprintTable struct {
+	Name        string   `json:"name"`
+	PKColumn    string   `json:"pk_column"`
+	RowCount    int64    `json:"row_count"`
+	ContentHash string   `json:"content_hash"`
+	Columns     []string `json:"columns,omitempty"`
+	Error       string   `json:"error,omitempty"`
+}
+
+// FingerprintRequest agent 拉线上表指纹。
+type FingerprintRequest struct {
+	OnlineDBID string   `json:"online_db_id"`
+	Tables     []string `json:"tables,omitempty"`
+}
+
+// FingerprintResult 批量指纹。
+type FingerprintResult struct {
+	OK     bool               `json:"ok"`
+	Tables []FingerprintTable `json:"tables"`
+}
+
+// FingerprintRemoteTables 计算线上 A 业务表 row_count + content_hash。
+// 哈希：sha256( table+"|"+pk+"|" + Σ json.dumps(row, sort_keys=True)+"\n" ) 取前 32 hex。
+func FingerprintRemoteTables(ctx context.Context, ch *Channel, req FingerprintRequest) (*FingerprintResult, error) {
+	if ch == nil {
+		return nil, fmt.Errorf("channel is nil")
+	}
+	db, err := AcquireRemote(ch.Remote.Driver, ch.Remote.DSN)
+	if err != nil {
+		return nil, wrapOpenRemote(err)
+	}
+	if err := EnsureMeta(ctx, db, ch.Remote.Driver); err != nil {
+		return nil, Retryablef("ensure meta: %v", err)
+	}
+	names, err := ListTables(ctx, db, ch.Remote.Driver)
+	if err != nil {
+		return nil, Retryablef("list tables: %v", err)
+	}
+	want := map[string]struct{}{}
+	for _, t := range req.Tables {
+		t = strings.TrimSpace(t)
+		if t != "" {
+			want[t] = struct{}{}
+		}
+	}
+	out := &FingerprintResult{OK: true, Tables: make([]FingerprintTable, 0, len(names))}
+	for _, name := range names {
+		if strings.HasPrefix(name, "_ajz_") {
+			continue
+		}
+		if len(want) > 0 {
+			if _, ok := want[name]; !ok {
+				continue
+			}
+		}
+		if !tableInChannel(ch, name) {
+			continue
+		}
+		fp, ferr := fingerprintOneTable(ctx, db, ch, name)
+		if ferr != nil {
+			fp.Error = ferr.Error()
+			out.OK = false
+		}
+		out.Tables = append(out.Tables, fp)
+	}
+	return out, nil
+}
+
+func fingerprintOneTable(ctx context.Context, db *sql.DB, ch *Channel, table string) (FingerprintTable, error) {
+	cols, err := listColumns(ctx, db, ch.Remote.Driver, table)
+	if err != nil {
+		return FingerprintTable{Name: table}, err
+	}
+	pkCol := "id"
+	if ch.PKColumns != nil && strings.TrimSpace(ch.PKColumns[table]) != "" {
+		pkCol = ch.PKColumns[table]
+	}
+	if !containsStr(cols, pkCol) {
+		for _, c := range []string{"id", "__row_id", "_row_id"} {
+			if containsStr(cols, c) {
+				pkCol = c
+				break
+			}
+		}
+		if !containsStr(cols, pkCol) && len(cols) > 0 {
+			pkCol = cols[0]
+		}
+	}
+	n, err := countRows(ctx, db, ch.Remote.Driver, table)
+	if err != nil {
+		return FingerprintTable{Name: table, PKColumn: pkCol, Columns: cols}, err
+	}
+	hash, err := contentHashOrdered(ctx, db, ch.Remote.Driver, table, pkCol)
+	if err != nil {
+		return FingerprintTable{Name: table, PKColumn: pkCol, RowCount: n, Columns: cols}, err
+	}
+	return FingerprintTable{
+		Name:        table,
+		PKColumn:    pkCol,
+		RowCount:    n,
+		ContentHash: hash,
+		Columns:     cols,
+	}, nil
+}
+
+func containsStr(ss []string, x string) bool {
+	for _, s := range ss {
+		if s == x {
+			return true
+		}
+	}
+	return false
+}
+
+func contentHashOrdered(ctx context.Context, db *sql.DB, driver Driver, table, pkCol string) (string, error) {
+	q := fmt.Sprintf(`SELECT * FROM %s ORDER BY %s`, quoteIdent(driver, table), quoteIdent(driver, pkCol))
+	rows, err := db.QueryContext(ctx, q)
+	if err != nil {
+		return "", err
+	}
+	defer rows.Close()
+	colNames, err := rows.Columns()
+	if err != nil {
+		return "", err
+	}
+	h := sha256.New()
+	_, _ = h.Write([]byte(table + "|" + pkCol + "|"))
+	ptrs := make([]any, len(colNames))
+	vals := make([]any, len(colNames))
+	for i := range vals {
+		ptrs[i] = &vals[i]
+	}
+	for rows.Next() {
+		for i := range vals {
+			vals[i] = nil
+		}
+		if err := rows.Scan(ptrs...); err != nil {
+			return "", err
+		}
+		m := make(map[string]any, len(colNames))
+		for i, c := range colNames {
+			m[c] = normalizeSQLValue(vals[i])
+		}
+		blob, err := stableJSON(m)
+		if err != nil {
+			return "", err
+		}
+		_, _ = h.Write(blob)
+		_, _ = h.Write([]byte("\n"))
+	}
+	if err := rows.Err(); err != nil {
+		return "", err
+	}
+	sum := hex.EncodeToString(h.Sum(nil))
+	if len(sum) > 32 {
+		sum = sum[:32]
+	}
+	return sum, nil
+}
+
+// stableJSON 按 key 排序，贴近 Python json.dumps(..., sort_keys=True, default=str)。
+func stableJSON(m map[string]any) ([]byte, error) {
+	keys := make([]string, 0, len(m))
+	for k := range m {
+		keys = append(keys, k)
+	}
+	sort.Strings(keys)
+	parts := make([]string, 0, len(keys))
+	for _, k := range keys {
+		kb, err := json.Marshal(k)
+		if err != nil {
+			return nil, err
+		}
+		vb, err := json.Marshal(m[k])
+		if err != nil {
+			// fallback string
+			vb, err = json.Marshal(fmt.Sprint(m[k]))
+			if err != nil {
+				return nil, err
+			}
+		}
+		parts = append(parts, string(kb)+":"+string(vb))
+	}
+	return []byte("{" + strings.Join(parts, ",") + "}"), nil
+}