Azure SDK中是否有任何RetryPolicy可以自动处理继续令牌？

发布于 2025-01-08 04:01:23 字数 90 浏览 3 评论 0 原文

对于查询，有时我会得到延续令牌，我想知道是否有针对 TableServiceContext 的 RetryPolicy 设置来自动处理令牌。

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纵山崖 2025-01-15 04:01:23

您不需要为此使用 RetryPolicy。有两个选项：

在查询中使用 .AsTableServiceQuery()。这会将您的查询转换为 CloudTableQuery<>对象，它本机处理延续标记。这是最简单的路线。例如：

var query = (from r in Rows
             where r.PartitionKey == "whatever"
             select r).AsTableServiceQuery();

否则您可以使用 Begin/EndExecuteSegmented() 并自己处理令牌。

对 CloudTableQuery 的说明<>

有一个对 CloudTableQuery<> 行为的间接引用。在 Scott Densmore 的博客上。但我还整理了以下相当混乱的代码来证明这一点。测试通过，并且它确实使用延续令牌来检索所有插入的实体。如果您使用 HTTP，您可以使用 Fiddler 进行观察，并看到令牌来回变化。

        [Test, Explicit]
        public void WriteAndReadALotOfRows()
        {
            CloudStorageAccount acct = CloudStorageAccount.Parse("PUT IN SOME CREDS HERE");
            TableServiceContext ctx = null;
            List<TestEntity> testEntities = new List<TestEntity>(2000);

            acct.CreateCloudTableClient().CreateTableIfNotExist("Test");

            //Create entities
            for (int i = 0; i < 2000; i++)
            {
                if (i % 100 == 0)
                {
                    if (ctx != null)
                    {
                        ctx.SaveChangesWithRetries(SaveChangesOptions.Batch);
                    }

                    ctx = new TableServiceContext(acct.TableEndpoint.AbsoluteUri, acct.Credentials);
                }
                TestEntity entity = new TestEntity(i);
                testEntities.Add(entity);
                ctx.AddObject("Test", entity);
            }

            ctx.SaveChangesWithRetries(SaveChangesOptions.Batch);

            ctx = new TableServiceContext(acct.TableEndpoint.AbsoluteUri, acct.Credentials);

            List<TestEntity> retrievedEntities = (from r in ctx.CreateQuery<TestEntity>("Test")
                                                  select r).AsTableServiceQuery().ToList();

            Assert.AreEqual(testEntities.Count, retrievedEntities.Count);
            Console.Out.WriteLine(retrievedEntities.Count); //prints 2000

            foreach (var insertedEntity in testEntities)
            {
                TestEntity retrievedEntity = retrievedEntities.First(r => r.RowKey == insertedEntity.RowKey);
                Assert.NotNull(retrievedEntity);
            }
        }

        public class TestEntity : TableServiceEntity
        {
            public TestEntity()
            {
            }

            public TestEntity(int id)
                : base("Test", id.ToString())
            {

            }
        }

You don't need to use a RetryPolicy for that. There are two options:

Use .AsTableServiceQuery() on your queries. That converts your query into a CloudTableQuery<> object, which natively handles continuation tokens. This is the easiest route. eg:

var query = (from r in Rows
             where r.PartitionKey == "whatever"
             select r).AsTableServiceQuery();

Otherwise you can use Begin/EndExecuteSegmented() and handle the tokens yourself.

Clarification on CloudTableQuery<>

There's an oblique reference to the behavior of CloudTableQuery<> on Scott Densmore's blog. But I also threw together the following, rather messy, code to prove it. The tests pass, and it does use continuation tokens to retrieve all the inserted entities. If you use HTTP, you can watch it with Fiddler and see the tokens go back and forth.

        [Test, Explicit]
        public void WriteAndReadALotOfRows()
        {
            CloudStorageAccount acct = CloudStorageAccount.Parse("PUT IN SOME CREDS HERE");
            TableServiceContext ctx = null;
            List<TestEntity> testEntities = new List<TestEntity>(2000);

            acct.CreateCloudTableClient().CreateTableIfNotExist("Test");

            //Create entities
            for (int i = 0; i < 2000; i++)
            {
                if (i % 100 == 0)
                {
                    if (ctx != null)
                    {
                        ctx.SaveChangesWithRetries(SaveChangesOptions.Batch);
                    }

                    ctx = new TableServiceContext(acct.TableEndpoint.AbsoluteUri, acct.Credentials);
                }
                TestEntity entity = new TestEntity(i);
                testEntities.Add(entity);
                ctx.AddObject("Test", entity);
            }

            ctx.SaveChangesWithRetries(SaveChangesOptions.Batch);

            ctx = new TableServiceContext(acct.TableEndpoint.AbsoluteUri, acct.Credentials);

            List<TestEntity> retrievedEntities = (from r in ctx.CreateQuery<TestEntity>("Test")
                                                  select r).AsTableServiceQuery().ToList();

            Assert.AreEqual(testEntities.Count, retrievedEntities.Count);
            Console.Out.WriteLine(retrievedEntities.Count); //prints 2000

            foreach (var insertedEntity in testEntities)
            {
                TestEntity retrievedEntity = retrievedEntities.First(r => r.RowKey == insertedEntity.RowKey);
                Assert.NotNull(retrievedEntity);
            }
        }

        public class TestEntity : TableServiceEntity
        {
            public TestEntity()
            {
            }

            public TestEntity(int id)
                : base("Test", id.ToString())
            {

            }
        }

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