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I think that microservices are just a deployment model of the service boundary and there should not be really a distinction between whether something is deploye

by alexk 8y ago

I think that microservices are just a deployment model of the service boundary and there should not be really a distinction between whether something is deployed as a microservice or a monolith, because application should support both for the scenarios when it makes sense. Consider the following API: UsersService: CreateUser GetUser AppCatalog: GetApp CreateApp What if AppCatalog and UsersService implement both local version of the interface and GRPC one? Then the distinction whether it's a microservice vs a monolith goes away, it becomes a matter of whether they are deployed in a single linux process or across boundaries of processes/servers. I have implemented this technique in teleport: https://github.com/gravitational/teleport/tree/master/lib/services https://github.com/gravitational/teleport/tree/master/lib/se... Integration test suite is run against RPC version and local version at the same time to make sure the contract remains the same: https://github.com/gravitational/teleport/blob/master/lib/services/suite/suite.go https://github.com/gravitational/teleport/blob/master/lib/se... A single teleport binary can be deployed on one server with all microservices, or multiple cluster scenarios. where the binary is simply instantiated with different roles: auth_service: enabled: yes node_service: enabled: no Is Teleport a monolith? Yes! Is it a micro-service app? Yes! I'm so happy that we don't have to think about this split any more.

qaq 8y ago
The question is transaction boundaries try unrolling a change that had to touch state of several services and one of the requests failed
- alexk 8y ago
  Right, because we write against DynamoDB/Etcd transactions were a non-option anyways, and we only have CompareAndSwap as a locking primitive https://github.com/gravitational/teleport/blob/master/lib/backend/backend.go#L46 https://github.com/gravitational/teleport/blob/master/lib/ba... In addition to that Golang's context https://golang.org/pkg/context/ https://golang.org/pkg/context/ is used to broadcast the failure of a distributed operation and release associated resources with it
  - Thaxll 8y ago
    DynamoDB has transactions now. https://aws.amazon.com/blogs/aws/new-amazon-dynamodb-transactions/ https://aws.amazon.com/blogs/aws/new-amazon-dynamodb-transac...
    - alexk 8y ago
      It's probably closer to multi-writes though, than transactions in a classic sense, but good improvement nevertheless.
      - Thaxll 8y ago
        It's a real transaction like MySQL or PG. https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/transactions.html https://docs.aws.amazon.com/amazondynamodb/latest/developerg...
AmrMostafa 8y ago
I don’t think it is ok to try and make service boundaries transparent and swappable. A service speaking to another service has to know the cost and overhead of the call it is making as otherwise it can’t provide an efficient interface

by alexk 8y ago

qaq 8y ago

The question is transaction boundaries try unrolling a change that had to touch state of several services and one of the requests failed

alexk 8y ago
Right, because we write against DynamoDB/Etcd transactions were a non-option anyways, and we only have CompareAndSwap as a locking primitive https://github.com/gravitational/teleport/blob/master/lib/backend/backend.go#L46 https://github.com/gravitational/teleport/blob/master/lib/ba... In addition to that Golang's context https://golang.org/pkg/context/ https://golang.org/pkg/context/ is used to broadcast the failure of a distributed operation and release associated resources with it
- Thaxll 8y ago
  DynamoDB has transactions now. https://aws.amazon.com/blogs/aws/new-amazon-dynamodb-transactions/ https://aws.amazon.com/blogs/aws/new-amazon-dynamodb-transac...
  - alexk 8y ago
    It's probably closer to multi-writes though, than transactions in a classic sense, but good improvement nevertheless.
    - Thaxll 8y ago
      It's a real transaction like MySQL or PG. https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/transactions.html https://docs.aws.amazon.com/amazondynamodb/latest/developerg...

AmrMostafa 8y ago

I don’t think it is ok to try and make service boundaries transparent and swappable. A service speaking to another service has to know the cost and overhead of the call it is making as otherwise it can’t provide an efficient interface