Slim - A Subscription Management API

Handle your customer subscription billing life cycle from end to end. Automate recurring billing, manage subscriptions, send professional tax-compliant invoices, and get paid on time, every time.

Getting Started

This subcription management API is built using the Crystal Language a statically type checked, compiled language with null reference checks, built in type inference.

Prerequisites

This project uses the following tools

• Crystal programming language
• Docker as container
• Postgres DB as database
• Kubernetes for deployments

MacOS Installation

brew install crystal
brew install kubernetes-cli kubectl
brew install postgres
brew install docker
brew install doctl

Installing

A step by step series of examples that tell you how to get a development env running

Say what the step will be

shards install
make build run

End with an example of getting some data out of the system or using it for a little demo

Running the tests

To run project tests

• Unit Tests - crystal spec spec/domain
• Endpoints Tests - crystal spec spec/endpoints (Must first run server in separate process make run)

Code Formatter

For code formatting this project uses Crystal built-in code formatter

crystal tool format
./bin/ameba

Crystal Ameba

A static code analysis tool for Crystal

crystal tool format
./bin/ameba

Deployment

Deployement is performed using GitLab CI/CD. Deployment scripts are available under the ./deploy directory

1. Setup a Kubenetes Cluster on Digital Ocean
2. Download the Certificate file using doctl with doctl kubernetes cluster kubeconfig save slim-cluster
3. Add new Kubernetes cluster in GitLab https://gitlab.com/eliasjpr/slim/clusters following these instructions https://docs.gitlab.com/ee/user/project/clusters/add_remove_clusters.html
4. Install Helm Tiller and GitLab Runner
5. Create a deploy token https://gitlab.com/eliasjpr/slim/-/settings/repository
6. Create a database url secret in kubernetes kubectl create secret generic databaseurl --from-literal=DATABASE_URL="{CONNECTION_STIRNG_HERE}"
7. Create a private docker registry secret in kubernetes with deploy token info create secret docker-registry regcred --docker-server=$CI_REGISTRY --docker-username='$CI_DEPLOY_USER' --docker-password='$CI_DEPLOY_PASSWORD' --docker-email='$GITLAB_USER_EMAIL --dry-run=true -o yaml | kubectl apply -f -
8. Run the pipeline

Run kubectl apply -f deploy to apply changes to the kubernetes cluster from local machine.

Gitlab AutoDevops on DigitalOcean k8s

Creating k8s cluster on DigitalOcean

1. Create a k8s cluster https://cloud.digitalocean.com/kubernetes/clusters
2. Install kubectl https://kubernetes.io/docs/tasks/tools/install-kubectl/
3. Download config file from cluster page to ~/.kube/config

Adding k8s cluster to Gitlab project

More info here: https://gitlab.com/help/user/project/clusters/index#adding-an-existing-kubernetes-cluster

Go to the group and add Kubernetes cluster https://gitlab.com/groups/urbica/-/clusters/

1. Create a gitlab service account in the default namespace:

kubectl create -f - <<EOF
  apiVersion: v1
  kind: ServiceAccount
  metadata:
    name: gitlab
    namespace: default
EOF

2. Create a cluster role binding to give the gitlab service account cluster-admin privileges:

kubectl create -f - <<EOF
kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: gitlab-cluster-admin
subjects:
- kind: ServiceAccount
  name: gitlab
  namespace: default
roleRef:
  kind: ClusterRole
  name: cluster-admin
  apiGroup: rbac.authorization.k8s.io
EOF

To determine the API URL, run

kubectl cluster-info | grep 'Kubernetes master' | awk '/http/ {print $NF}'

To determine the Token, list the secrets by running:

kubectl get secrets

Note the name of the secret you need the token for. Get the token for the appropriate secret by running:

kubectl get secret <SECRET_NAME> -o jsonpath="{['data']['token']}" | base64 -D

To determine the CA certificate, run:

kubectl get secret <SECRET_NAME> -o jsonpath="{['data']['ca\.crt']}" | base64 -D

Don't forget to enable RBAC.

On the cluster settings page install:

• Helm Tiller
• Ingress
• Cert Manager

After installing Ingress, check that external ip is set and pointing to the right load balancer https://gitlab.com/help/user/project/clusters/index.md#getting-the-external-ip-address

Built With

• Crystal - The web framework used
• Crystal Shards - Dependency Management

Contributing

Please read CONTRIBUTING.md for details on our code of conduct, and the process for submitting pull requests to us.

Versioning

We use SemVer for versioning. For the versions available, see the tags on this repository.

License

This project is licensed under the MIT License - see the LICENSE.md file for details