ExtremeSystem.Example

This is example project for using Extreme.System. It is set of building block usefull for CQRS+ES systems.

Dependencies

EventStore

Running system

Get the example

$ git clone https://github.com/exponentially/extreme_system_example.git
$ cd extreme_system_example
$ mix deps.get

Run local event store

First time pull docker image:

$ docker run --name eventstore4.1 -it -p 2113:2113 -p 1113:1113 -e EVENTSTORE_RUN_PROJECTIONS=all -e EVENTSTORE_START_STANDARD_PROJECTIONS=true eventstore/eventstore

Docker container can be stopped as follows

$ docker stop eventstore4.1

Next time you want to start it, just start container:

$ docker start eventstore4.1

Run beam nodes (api and users)

• From new terminal go to api folder and run it:

  $ cd apps/api $ ./run.sh

  You should have opened iex with something like:

Erlang/OTP 21 [erts-10.0.5] [source] [64-bit] [smp:4:4] [ds:4:4:10] [async-threads:1] [hipe]

2018-09-07 14:24:16.278 [info] pid=<0.295.0> Starting ExtremeSystem.Example.Api in :normal mode
2018-09-07 14:24:16.282 [info] pid=<0.295.0> Trying to connect node :example_api@mystique to: ["ExSysApi", "ExSysUsers"]
2018-09-07 14:24:16.285 [error] pid=<0.58.0>
** Cannot get connection id for node :example_api@mystique

2018-09-07 14:24:16.353 [info] pid=<0.312.0> Running ExtremeSystem.Example.Api.Endpoint with Cowboy using http://0.0.0.0:4000
Interactive Elixir (1.7.3) - press Ctrl+C to exit (type h() ENTER for help)
iex(example_api@mystique)1> 2018-09-07 14:24:17.305 [info] pid=<0.300.0> Connected nodes: []

• From the other terminal, go to users folder and run it:

  $ cd apps/users $ ./run.sh

Nodes should connect to cluster as you may see in iex:

Erlang/OTP 21 [erts-10.0.5] [source] [64-bit] [smp:4:4] [ds:4:4:10] [async-threads:1] [hipe]

2018-09-07 14:25:43.259 [info] pid=<0.266.0> Starting ExtremeSystem.Example.Users in :normal mode
2018-09-07 14:25:43.262 [info] pid=<0.266.0> Trying to connect node :es_users@mystique to: ["ExSysApi", "ExSysUsers"]
2018-09-07 14:25:43.282 [error] pid=<0.58.0>
** Cannot get connection id for node :es_users@mystique

2018-09-07 14:25:43.315 [info] pid=<0.286.0> Connecting Extreme to 127.0.0.1:1113
2018-09-07 14:25:43.316 [info] pid=<0.286.0> Successfully connected to EventStore using protocol version 3
Interactive Elixir (1.7.3) - press Ctrl+C to exit (type h() ENTER for help)
iex(es_users@mystique)1> 2018-09-07 14:25:44.283 [info] pid=<0.272.0> Connected nodes: [:example_api@mystique]

Calling API

There is Postman collection in apps/api/doc/ExtremeSystem.Example.postman_collection.json

You can try it using curl as well:

• Register new user:

curl -X POST \
  http://localhost:4000/users \
  -v \
  -H 'Accept: application/json' \
  -H 'Cache-Control: no-cache' \
  -H 'Content-Type: application/json' \
  -d '{
    "email": "user.1@example.com",
    "name": "Milan"
}'

Last line of output should be:

{"id":"05c03d0c-b29a-11e8-aff9-acbc32d4fe0b"}

If so, that is ID of your new User. You can confirm that in EventStore as well @ http://localhost:2113/web/index.html#/streams/ex_users-05c03d0c-b29a-11e8-aff9-acbc32d4fe0b

• Once you have registered user, you can change it's name:

curl -X PUT \
  http://localhost:4000/users/05c03d0c-b29a-11e8-aff9-acbc32d4fe0b \
  -v \
  -H 'Accept: application/json' \
  -H 'Cache-Control: no-cache' \
  -H 'Content-Type: application/json' \
  -d '{
  "version": 2,
    "name": "Milan II"
}'

You should get 204 back and new aggregate version in header:

< x-aggregate-version: 2

You should also notice new event in that users stream.