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Samples

Azure Service Bus Hierarchy Migration Sample

NuGet Package: NServiceBus.Transport.AzureServiceBus (4.x)
Target Version: NServiceBus 9.x

Prerequisites

An environment variable named AzureServiceBus_ConnectionString with the connection string for the Azure Service Bus namespace.

Code walk-through

This sample demonstrates how an endpoint can be migrated without any downtime from one topic to another:

  • Endpoint1 publishes Event1 messages and subscribes to Event2 messages.
  • Endpoint2 subscribes to Event1 messages and publishes Event2 messages.
  • Migration does a step by step live migration of Endpoint2 while the endpoints are running and exchanging messages with each other.

Sample output

The migration program creates self-explanatory output during the migration process.

------ Infrastructure cleanup ------

⚠ Make sure 'Endpoint1' and 'Endpoint2' are not running for the infrastructure cleanup to succeed.

Cleanup infrastructure from previous runs of this sample? [y/n] (y): y
------ Deleted infrastructure ------
┌────────────────────────┐
│     Deleted Topics     │
├────────────────────────┤
│  bundle-to-publish-to  │
│ bundle-to-subscribe-to │
└────────────────────────┘
┌─────────────────────────────────────────────────────┐
│                   Deleted Queues                    │
├─────────────────────────────────────────────────────┤
│      samples.asbs.hierarchymigration.endpoint1      │
│      samples.asbs.hierarchymigration.endpoint2      │
│ samples.asbs.hierarchymigration.endpoint2.migration │
└─────────────────────────────────────────────────────┘

------ Topology before migration -----
Topics
└── bundle-to-publish-to
    ├── Samples.ASBS.HierarchyMigration.Endpoint1
    │   ├── $default: 1=0
    │   ├── Event2: [NServiceBus.EnclosedMessageTypes] LIKE '%Event2%'
    │   └── samples.asbs.hierarchymigration.endpoint1
    └── Samples.ASBS.HierarchyMigration.Endpoint2
        ├── $default: 1=0
        ├── Event1: [NServiceBus.EnclosedMessageTypes] LIKE '%Event1%'
        └── samples.asbs.hierarchymigration.endpoint2
Queues
├── samples.asbs.hierarchymigration.endpoint1
└── samples.asbs.hierarchymigration.endpoint2

----- Endpoints should be running ------

⚠ Start 'Endpoint1' and 'Endpoint2' and wait a bit until some messages are published. After some time...
:: Press any key to setup the sample topology

----- The 'bundle-to-subscribe-to' topic has been setup ------
Topics
├── bundle-to-publish-to
│   ├── Samples.ASBS.HierarchyMigration.Endpoint1
│   │   ├── $default: 1=0
│   │   ├── Event2: [NServiceBus.EnclosedMessageTypes] LIKE '%Event2%'
│   │   └── samples.asbs.hierarchymigration.endpoint1
│   └── Samples.ASBS.HierarchyMigration.Endpoint2
│       ├── $default: 1=0
│       ├── Event1: [NServiceBus.EnclosedMessageTypes] LIKE '%Event1%'
│       └── samples.asbs.hierarchymigration.endpoint2
└── bundle-to-subscribe-to
Queues
├── samples.asbs.hierarchymigration.endpoint1
└── samples.asbs.hierarchymigration.endpoint2
----- The forward rule on topic 'bundle-to-publish-to' has been setup ------
Topics
├── bundle-to-publish-to
│   ├── Samples.ASBS.HierarchyMigration.Endpoint1
│   │   ├── $default: 1=0
│   │   ├── Event2: [NServiceBus.EnclosedMessageTypes] LIKE '%Event2%'
│   │   └── samples.asbs.hierarchymigration.endpoint1
│   ├── Samples.ASBS.HierarchyMigration.Endpoint2
│   │   ├── $default: 1=0
│   │   ├── Event1: [NServiceBus.EnclosedMessageTypes] LIKE '%Event1%'
│   │   └── samples.asbs.hierarchymigration.endpoint2
│   └── forwardTo-bundle-to-subscribe-to
│       ├── $default: 1=1
│       └── bundle-to-subscribe-to
└── bundle-to-subscribe-to
Queues
├── samples.asbs.hierarchymigration.endpoint1
└── samples.asbs.hierarchymigration.endpoint2
----- The migration queue 'samples.asbs.hierarchymigration.endpoint2.migration' has been setup -----
Topics
├── bundle-to-publish-to
│   ├── Samples.ASBS.HierarchyMigration.Endpoint1
│   │   ├── $default: 1=0
│   │   ├── Event2: [NServiceBus.EnclosedMessageTypes] LIKE '%Event2%'
│   │   └── samples.asbs.hierarchymigration.endpoint1
│   ├── Samples.ASBS.HierarchyMigration.Endpoint2
│   │   ├── $default: 1=0
│   │   ├── Event1: [NServiceBus.EnclosedMessageTypes] LIKE '%Event1%'
│   │   └── samples.asbs.hierarchymigration.endpoint2
│   └── forwardTo-bundle-to-subscribe-to
│       ├── $default: 1=1
│       └── bundle-to-subscribe-to
└── bundle-to-subscribe-to
Queues
├── samples.asbs.hierarchymigration.endpoint1
├── samples.asbs.hierarchymigration.endpoint2
└── samples.asbs.hierarchymigration.endpoint2.migration
----- The subscription 'Samples.ASBS.HierarchyMigration.Endpoint2' on 'topic bundle-to-subscribe-to' has been setup ------
Topics
├── bundle-to-publish-to
│   ├── Samples.ASBS.HierarchyMigration.Endpoint1
│   │   ├── $default: 1=0
│   │   ├── Event2: [NServiceBus.EnclosedMessageTypes] LIKE '%Event2%'
│   │   └── samples.asbs.hierarchymigration.endpoint1
│   ├── Samples.ASBS.HierarchyMigration.Endpoint2
│   │   ├── $default: 1=0
│   │   ├── Event1: [NServiceBus.EnclosedMessageTypes] LIKE '%Event1%'
│   │   └── samples.asbs.hierarchymigration.endpoint2
│   └── forwardTo-bundle-to-subscribe-to
│       ├── $default: 1=1
│       └── bundle-to-subscribe-to
└── bundle-to-subscribe-to
    └── Samples.ASBS.HierarchyMigration.Endpoint2
        ├── $default: 1=0
        └── samples.asbs.hierarchymigration.endpoint2.migration
Queues
├── samples.asbs.hierarchymigration.endpoint1
├── samples.asbs.hierarchymigration.endpoint2
└── samples.asbs.hierarchymigration.endpoint2.migration
----- The subscription 'Samples.ASBS.HierarchyMigration.Endpoint2' on topic 'bundle-to-subscribe-to' with the necessary rules ------
Topics
├── bundle-to-publish-to
│   ├── Samples.ASBS.HierarchyMigration.Endpoint1
│   │   ├── $default: 1=0
│   │   ├── Event2: [NServiceBus.EnclosedMessageTypes] LIKE '%Event2%'
│   │   └── samples.asbs.hierarchymigration.endpoint1
│   ├── Samples.ASBS.HierarchyMigration.Endpoint2
│   │   ├── $default: 1=0
│   │   ├── Event1: [NServiceBus.EnclosedMessageTypes] LIKE '%Event1%'
│   │   └── samples.asbs.hierarchymigration.endpoint2
│   └── forwardTo-bundle-to-subscribe-to
│       ├── $default: 1=1
│       └── bundle-to-subscribe-to
└── bundle-to-subscribe-to
    └── Samples.ASBS.HierarchyMigration.Endpoint2
        ├── $default: 1=0
        ├── Event1: [NServiceBus.EnclosedMessageTypes] LIKE '%Event1%'
        └── samples.asbs.hierarchymigration.endpoint2.migration
Queues
├── samples.asbs.hierarchymigration.endpoint1
├── samples.asbs.hierarchymigration.endpoint2
└── samples.asbs.hierarchymigration.endpoint2.migration

🔎 Notice how Endpoint2 temporarily stops receiving events

:: Press any key to continue with the migration

----- The subscription 'Samples.ASBS.HierarchyMigration.Endpoint2' on topic 'bundle-to-publish-to' has been deleted ------
Topics
├── bundle-to-publish-to
│   ├── Samples.ASBS.HierarchyMigration.Endpoint1
│   │   ├── $default: 1=0
│   │   ├── Event2: [NServiceBus.EnclosedMessageTypes] LIKE '%Event2%'
│   │   └── samples.asbs.hierarchymigration.endpoint1
│   └── forwardTo-bundle-to-subscribe-to
│       ├── $default: 1=1
│       └── bundle-to-subscribe-to
└── bundle-to-subscribe-to
    └── Samples.ASBS.HierarchyMigration.Endpoint2
        ├── $default: 1=0
        ├── Event1: [NServiceBus.EnclosedMessageTypes] LIKE '%Event1%'
        └── samples.asbs.hierarchymigration.endpoint2.migration
Queues
├── samples.asbs.hierarchymigration.endpoint1
├── samples.asbs.hierarchymigration.endpoint2
└── samples.asbs.hierarchymigration.endpoint2.migration
----- Checking migration queue status ------
⚠ There are currently 3 messages in the migration queue.

----- The queue 'samples.asbs.hierarchymigration.endpoint2.migration' forwarding to 'samples.asbs.hierarchymigration.endpoint2' has been setup -----
Topics
├── bundle-to-publish-to
│   ├── Samples.ASBS.HierarchyMigration.Endpoint1
│   │   ├── $default: 1=0
│   │   ├── Event2: [NServiceBus.EnclosedMessageTypes] LIKE '%Event2%'
│   │   └── samples.asbs.hierarchymigration.endpoint1
│   └── forwardTo-bundle-to-subscribe-to
│       ├── $default: 1=1
│       └── bundle-to-subscribe-to
└── bundle-to-subscribe-to
    └── Samples.ASBS.HierarchyMigration.Endpoint2
        ├── $default: 1=0
        ├── Event1: [NServiceBus.EnclosedMessageTypes] LIKE '%Event1%'
        └── samples.asbs.hierarchymigration.endpoint2.migration
Queues
├── samples.asbs.hierarchymigration.endpoint1
├── samples.asbs.hierarchymigration.endpoint2
└── samples.asbs.hierarchymigration.endpoint2.migration
    └── samples.asbs.hierarchymigration.endpoint2
----- Checking forwarding progress in the migration queue ------
⌛ Everything forwarded. Moving on
------ The subscription 'Samples.ASBS.HierarchyMigration.Endpoint2' on topic 'bundle-to-subscribe-to' has been changed to forward to… ------
Topics
├── bundle-to-publish-to
│   ├── Samples.ASBS.HierarchyMigration.Endpoint1
│   │   ├── $default: 1=0
│   │   ├── Event2: [NServiceBus.EnclosedMessageTypes] LIKE '%Event2%'
│   │   └── samples.asbs.hierarchymigration.endpoint1
│   └── forwardTo-bundle-to-subscribe-to
│       ├── $default: 1=1
│       └── bundle-to-subscribe-to
└── bundle-to-subscribe-to
    └── Samples.ASBS.HierarchyMigration.Endpoint2
        ├── $default: 1=0
        ├── Event1: [NServiceBus.EnclosedMessageTypes] LIKE '%Event1%'
        └── samples.asbs.hierarchymigration.endpoint2
Queues
├── samples.asbs.hierarchymigration.endpoint1
├── samples.asbs.hierarchymigration.endpoint2
└── samples.asbs.hierarchymigration.endpoint2.migration
    └── samples.asbs.hierarchymigration.endpoint2
:: Press any key to continue with the migration

------ The queue 'samples.asbs.hierarchymigration.endpoint2.migration' was removed ------
Topics
├── bundle-to-publish-to
│   ├── Samples.ASBS.HierarchyMigration.Endpoint1
│   │   ├── $default: 1=0
│   │   ├── Event2: [NServiceBus.EnclosedMessageTypes] LIKE '%Event2%'
│   │   └── samples.asbs.hierarchymigration.endpoint1
│   └── forwardTo-bundle-to-subscribe-to
│       ├── $default: 1=1
│       └── bundle-to-subscribe-to
└── bundle-to-subscribe-to
    └── Samples.ASBS.HierarchyMigration.Endpoint2
        ├── $default: 1=0
        ├── Event1: [NServiceBus.EnclosedMessageTypes] LIKE '%Event1%'
        └── samples.asbs.hierarchymigration.endpoint2
Queues
├── samples.asbs.hierarchymigration.endpoint1
└── samples.asbs.hierarchymigration.endpoint2
🏅 Migration done.
Stop 'Endpoint2' and change:
`transport.Topology = TopicTopology.Single("bundle-to-publish-to");`

to

`transport.Topology = TopicTopology.Hierarchy("bundle-to-publish-to", "bundle-to-subscribe-to");`

and then start 'Endpoint2'.

Viewing in-flight messages

For every supported migration step, the migration console will wait for any key to continue, which allows for inspecting the queues, topics, and subscriptions on the Azure Portal or a third-party tool during the migration process.

The following queues for the two endpoints can be viewed in the Azure Portal or a third-party tool:

  • samples.asbs.hierarchymigration.endpoint1
  • samples.asbs.hierarchymigration.endpoint2
  • samples.asbs.hierarchymigration.endpoint2.migration

The following topics can be inspected:

  • bundle-to-publish-to
  • bundle-to-subscribe-to

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