f536987a7e
- doc: add comment
220 lines
9.0 KiB
Go
220 lines
9.0 KiB
Go
package transaction
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import (
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"context"
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"database/sql"
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"errors"
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"fmt"
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"strings"
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"time"
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)
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// backendService backend 容器部署事务使用的服务名常量。
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//
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// 该常量同时用于部署表相关事务的归属判定与历史查询的条件过滤。
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const backendService = "backend"
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// BackendContainerDeployment is the last container slot committed for backend.
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// Runtime inspection remains authoritative for the current external state; this
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// record distinguishes a fresh installation from loss or drift after deployment.
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//
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// BackendContainerDeployment backend 最近一次提交使用的容器槽位持久化记录。
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// 它只保留单行(singleton_id=1),用于区分全新安装与部署后丢失/漂移:运行时 inspect
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// 始终是当前外部状态的权威来源,而本记录提供“机器是否曾成功部署”的持久化证据。
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type BackendContainerDeployment struct {
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ActivePort int // 当前对外服务的端口,只能是 8080 或 8081。
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ContainerName string // 生效容器的名称。
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ImageDigest string // 生效容器镜像的摘要。
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ContainerID string // 生效容器的 ID。
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TransactionID string // 提交本次部署的事务 ID。
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UpdatedAt time.Time // 记录最近一次更新(提交)时间(UTC)。
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}
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// BackendContainerDeployment returns the single committed backend container state.
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//
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// BackendContainerDeployment 返回当前唯一已提交的 backend 容器部署记录。参数 ctx
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// 用于取消查询。若尚无部署记录则返回 ErrNotFound。
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func (s *Store) BackendContainerDeployment(ctx context.Context) (BackendContainerDeployment, error) {
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return scanBackendContainerDeployment(s.db.QueryRowContext(ctx, `
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SELECT active_port, container_name, image_digest, container_id,
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transaction_id, updated_at
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FROM backend_container_deployment
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WHERE singleton_id = 1`))
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}
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// HasCommittedBackendContainerTransactionHistory reports whether this store
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// contains a committed container backend transaction. This is the legacy
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// deployment evidence used when a database predates the deployment table.
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// Failed and rolled-back first-install attempts do not mark a machine deployed.
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//
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// HasCommittedBackendContainerTransactionHistory 报告当前存储中是否存在已提交的
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// backend 容器事务历史。当数据库版本早于部署表(缺少 backend_container_deployment
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// 单例记录)时,它作为历史部署证据使用:只要存在 service 为 backend 且幂等键匹配
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// backend:container:* 且状态为 COMMITTED 的事务,即视为该机器已部署。失败或回滚的
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// 首次安装尝试不会把机器标记为已部署。参数 ctx 用于取消查询,返回是否已部署的布尔值
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// 及可能的错误。
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func (s *Store) HasCommittedBackendContainerTransactionHistory(ctx context.Context) (bool, error) {
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var found int
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if err := s.db.QueryRowContext(ctx, `
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SELECT EXISTS (
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SELECT 1
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FROM transactions
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WHERE service = ?
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AND idempotency_key GLOB 'backend:container:*'
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AND state = ?
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)`, backendService, StateCommitted).Scan(&found); err != nil {
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return false, fmt.Errorf("query committed backend container transaction history: %w", err)
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}
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return found == 1, nil
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}
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// CommitBackendContainerDeployment atomically records the active container and
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// commits its transaction. A crash cannot leave COMMITTED without the matching
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// deployment row, or publish a deployment row for an unfinished transaction.
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//
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// CommitBackendContainerDeployment 原子地记录生效容器并把其事务提交为 COMMITTED。
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// 参数 ctx 用于取消操作;transactionID 为待提交的事务 ID,必须与 backend 服务匹配
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// 且当前状态为 DRAINING;deployment 为要写入的容器部署信息;message 为随状态事件
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// 记录的信息。返回值为更新后的最新事务快照。由于部署行写入与事务状态提交在同一个
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// Serializable 事务内完成,崩溃不可能留下“已 COMMITTED 却没有对应部署行”或“未完成
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// 事务却已发布部署行”的中间状态。
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func (s *Store) CommitBackendContainerDeployment(
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ctx context.Context,
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transactionID string,
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deployment BackendContainerDeployment,
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message string,
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) (Transaction, error) {
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if transactionID == "" || strings.TrimSpace(transactionID) != transactionID {
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return Transaction{}, errors.New("exact transaction ID is required")
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}
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if err := validateBackendContainerDeployment(deployment); err != nil {
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return Transaction{}, err
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}
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tx, err := s.db.BeginTx(ctx, &sql.TxOptions{Isolation: sql.LevelSerializable})
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if err != nil {
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return Transaction{}, fmt.Errorf("begin backend container deployment commit: %w", err)
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}
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defer tx.Rollback()
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record, err := getTransactionByID(ctx, tx, transactionID)
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if err != nil {
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return Transaction{}, err
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}
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if record.Service != backendService {
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return Transaction{}, fmt.Errorf("transaction %s service must be %s", transactionID, backendService)
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}
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if record.State != StateDraining {
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return Transaction{}, &TransitionError{From: record.State, To: StateCommitted}
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}
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now := s.now().UTC()
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_, err = tx.ExecContext(ctx, `
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INSERT INTO backend_container_deployment (
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singleton_id, active_port, container_name, image_digest,
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container_id, transaction_id, updated_at
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) VALUES (1, ?, ?, ?, ?, ?, ?)
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ON CONFLICT(singleton_id) DO UPDATE SET
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active_port = excluded.active_port,
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container_name = excluded.container_name,
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image_digest = excluded.image_digest,
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container_id = excluded.container_id,
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transaction_id = excluded.transaction_id,
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updated_at = excluded.updated_at`,
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deployment.ActivePort,
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deployment.ContainerName,
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deployment.ImageDigest,
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deployment.ContainerID,
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transactionID,
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formatTime(now),
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)
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if err != nil {
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return Transaction{}, fmt.Errorf("write backend container deployment: %w", err)
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}
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result, err := tx.ExecContext(ctx, `
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UPDATE transactions
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SET state = ?, version = version + 1, updated_at = ?
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WHERE id = ? AND version = ? AND state = ?`,
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StateCommitted,
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formatTime(now),
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transactionID,
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record.Version,
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StateDraining,
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)
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if err != nil {
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return Transaction{}, fmt.Errorf("commit backend container transaction state: %w", err)
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}
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rows, err := result.RowsAffected()
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if err != nil {
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return Transaction{}, fmt.Errorf("read committed backend container transaction rows: %w", err)
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}
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if rows != 1 {
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return Transaction{}, errors.New("backend container transaction changed concurrently")
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}
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if err := insertEvent(ctx, tx, transactionID, "", "TRANSACTION_STATE_CHANGED", record.State, StateCommitted, message, now); err != nil {
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return Transaction{}, err
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}
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if err := tx.Commit(); err != nil {
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return Transaction{}, fmt.Errorf("commit backend container deployment: %w", err)
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}
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record.State = StateCommitted
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record.Version++
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record.UpdatedAt = now
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return record, nil
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}
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// validateBackendContainerDeployment 校验 backend 容器部署信息的合法性。
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//
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// ActivePort 必须是 8080 或 8081;ContainerName、ImageDigest、ContainerID 均不能
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// 为空且不能含有首尾空白(即必须是精确值)。全部通过返回 nil,否则返回描述具体
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// 问题的错误。
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func validateBackendContainerDeployment(deployment BackendContainerDeployment) error {
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if deployment.ActivePort != 8080 && deployment.ActivePort != 8081 {
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return fmt.Errorf("backend container deployment port must be 8080 or 8081: %d", deployment.ActivePort)
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}
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for _, field := range []struct {
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name string
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value string
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}{
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{"container name", deployment.ContainerName},
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{"image digest", deployment.ImageDigest},
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{"container ID", deployment.ContainerID},
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} {
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if field.value == "" || strings.TrimSpace(field.value) != field.value {
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return fmt.Errorf("exact backend container %s is required", field.name)
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}
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}
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return nil
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}
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// scanBackendContainerDeployment 从单行结果反序列化一条 backend 容器部署记录。
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//
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// 参数 row 提供扫描能力,返回反序列化后的 BackendContainerDeployment。将持久化的
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// updated_at 文本解析为 time.Time。未命中返回 ErrNotFound,其他解析失败返回包装后
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// 的错误。
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func scanBackendContainerDeployment(row rowScanner) (BackendContainerDeployment, error) {
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var deployment BackendContainerDeployment
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var updatedAt string
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if err := row.Scan(
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&deployment.ActivePort,
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&deployment.ContainerName,
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&deployment.ImageDigest,
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&deployment.ContainerID,
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&deployment.TransactionID,
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&updatedAt,
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); err != nil {
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if errors.Is(err, sql.ErrNoRows) {
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return BackendContainerDeployment{}, ErrNotFound
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}
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return BackendContainerDeployment{}, fmt.Errorf("scan backend container deployment: %w", err)
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}
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parsed, err := parseTime(updatedAt)
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if err != nil {
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return BackendContainerDeployment{}, fmt.Errorf("parse backend container deployment update time: %w", err)
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}
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deployment.UpdatedAt = parsed
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return deployment, nil
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}
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