Winter

Distributed table based KV server

Introduction

Winter is a distributed in memory key-value store, the term table based comes from the idea that each group of data lives in isolation. If you want to PUT/GET/DELETE/etc... you must specify the table on which these commands are going to be actioned. Each table runs in a supervision tree which makes the server more responsive and reliable against application and network level errors.

Building

Build the image from the Dockerfile and specify BUILD_ENV as part of the build configuration.

Then specify RECEPTOR_PORT when running it.

Example

> docker build --build-arg BUILD_ENV=prod -t name:tag .

> docker run -e RECEPTOR_PORT=1010 -it name:tag

## Alternatively, you can pull it from the hub
> docker pull aguxez/winter:latest

Connecting

Connections happen through TCP. Open a connection to the specified RECEPTOR_PORT and you should be able to start sending commands.

Supported Commands

Click to show

All commands in this section, except for CREATE will also return a missing table message if the table hasn't been created

CREATE table

Creates a new table

Example

> CREATE table
created

> CREATE table
already created

GET table key

Gets key on table

Example

> GET table key
nil

> PUTNEW table key data
ok

> GET table key
data

PUTNEW table key data

Puts data under key on table. This command is immutable.

Example

> PUTNEW table key more data
ok

> PUTNEW table key another chunk of data
ok

> GET table key
more data

DELETE table key

Deletes key on table

Example

> PUTNEW table key chunk
ok

> DELETE table key
ok

> GET table key
nil

Distributed workload

Click to show

Winter can work as a distributed deployment if you wish to do so, based on a toggle (IS_DISTRIBUTED=true) at startup, Winter will set the necessary configuration. At this moment Winter only works with Kubernetes through DNS configuration. You have to set two env vars for this to work properly if IS_DISTRIBUTED=true

• DNS_SERVICE_NAME
• DNS_APPLICATION_NAME

In the k8s folder you can see an example configuration (which can be easily deployed to minikube) and in that example DNS_SERVICE_NAME=winter-nodes and DNS_APPLICATION_NAME=winter.

Nodes discovery/removal works automatically by default.

TODO

• More friendly configuration so we can abstract the need to know Elixir for distributed workload.