➡️Click me to clone this repo

This example illustrates all of the core event sourcing building blocks applied to a simplified banking model. In this sample, we have modeled a bank account aggregate, projector, process manager, and an artificial gateway that can be used for testing simulated inter-bank transfers (processes/sagas).

This particular repository is a template, meant to demonstrate a GitOps flow for deploying a wasmCloud application to Cosmonic. The application is a simple banking example, which is a fork of the Concordance Banking Example.

In order to try this repository out, you will need:

1. A Kubernetes cluster with access to deploy to. For local testing, we recommend kind.
2. Kubectl with kubeconfig pointing to your cluster from the previous step. Use kubectl config view to validate.
3. Argo CD deployed into your cluster. For local testing, we recommend following Argo's Getting Started guide for quick setup.
4. cosmo cli v0.23.2 or later installed. Use cosmo --version to validate.
5. Account on Cosmonic. It's free to sign up!

In this demo, we will walk through a set of steps with each step building on the previous one. With that being said, the steps we will walk through are as follows:

1. Logging into Cosmonic
2. Connect your Kubernetes cluster to Cosmonic
3. Deploy the initial state (v0.0.0) of the demo application
4. Deploy v0.1.0 release
5. Deploy v0.2.0 release
6. Deploy v0.3.0 release

Before you proceed with the rest of this demo, you will need to make sure that you are logged in on the command-line to Cosmonic.

To check whether you are logged in or not, you can run:

cosmo whoami

If you have not yet logged in, you will see the following message, prompting you to do so:

$ cosmo whoami
Failed to open user credentials. Have you run `cosmo login`?

Once you are logged in, you will be greeted with a message that should look something like the following with the actual values replaced with your account specific values:

$ cosmo whoami
Current user information:

Constellation IDs: dd722aff-7849-4f72-8f63-ca843999202c
NATS public key: AAYOBUJ5QG5YF3OYYSJERTW23SPWBTUF2AJRW3C4HPPVV5YOOM6LZWSV

With your cosmo cli now logged in, you are ready to proceed with the rest of the demo!

In order to begin deploying WebAssembly-based applications to your Kubernetes cluster, you will need to connect your cluster with Cosmonic.

To connect your Kubernetes cluster, we will deploy cosmo-controller in to your cluster by running the following:

cosmo connect k8s

By default without any options provided, this will:

1. Connect to your Cosmonic account, prompting you to login if you have not already.
2. Attempt to establish a connection to locally configured Kubernetes credentials by checking for existence of KUBECONFIG environment variable and then ~/.kube/config file.
3. Configure and deploy cosmo-controller into the Kubernetes cluster using the locally configured credentials.
4. Deploy a set of wasmCloud hosts using the bundled CosmonicHostConfig CRD to the specified namespace (or default namespace if no namespace is provided).
5. Deploy Kubernetes Applier Capability Provider and Kubernetes Applier Actor as wadm-managed applications into your constellation, which will help expose any HTTP-based actors as services inside of your Kubernetes cluster

Once cosmo connect k8s has run successfully, you should see the following output with the actual values matching your account:

$ cosmo connect k8s
Successfully connected to constellation [dd722aff-7849-4f72-8f63-ca843999202c]
✅ Successfully connected to k8s cluster
✅ Successfully configured controller
ℹ️ Applying additional host labels:
✅ Successfully started wasmcloud hosts
✅ Wadm manifest deployed. You can check deployment status at https://app.cosmonic.com/constellation/applications/detail/cosmo-connect-127-0-0-1-default?view=manifest
🔗 Kubernetes cluster successfully connected!
🚀 Open Cosmonic (https://app.cosmonic.com) to interact with your Kubernetes hosts.

With your Kubernetes cluster successfully connected to Cosmonic, you are ready to proceed to the next step of the demo!

For the next part, you will need to clone down your version of this repository that you have created based on the cosmonic/concordance-gitops template.

Once you have cloned the repository to your machine, you will find setup/argocd-application.yaml at the root of this repository, which defines a simple Argo CD directory-type Application.

To deploy this application in to your cluster, at the root of this repository run the following command:

kubectl apply -f setup/argocd-application.yaml -n argocd

When you apply the Argo CD Application definition to your cluster, Argo CD will check out the source code from your repository and deploy the wadm application defined at the root of this repository (in the wadm.yaml file) to the default namespace in your Kubernetes cluster.

To check the on the state of deployed application, you can check on it by running:

kubectl get app/bank-account -n default

Or you can check via Argo CD by running:

kubectl get applications.argoproj.io/bank-account --namespace argocd

Once the application has successfully been deployed, you can navigate to https://app.cosmonic.com/constellation/applications/detail/bank-account?view=manifest to see your application.

Under the "Wormholes" section you will find a link that you can click to view the application running live:

With the application now deployed to your Kubernetes cluster, you are ready to iterate!

Now that you have the initial version of the application, it's time to make some changes.

As part of the initialization we've set up for this repository, we've created 3 release branches (named release/v0.1.0 .. release/v0.3.0) that each have a set of changes which build on the previous release (or the initial state in the case of v0.1.0) as a way to demonstrate how you can use GitOps and wadm together to roll out different changes throughout your application's lifecycle.

So to get going with the first set of changes, what you will want to do is set up a Pull Request for the release/v0.1.0 branch against main. Here's a link for you to do exactly that:

https://github.com/sgfractal/concordance-credit/compare/release/v0.1.0?expand=1

Once you merge this Pull Request, Argo will detect that there are changes and push up the changes in the wadm.yaml file. Afterwards, you will be able to reload the Wormhole from before to see the changes. You’ll see two new events, CreateAccount and AccountCreated, corresponding to the request to create an account and the event indicating that the account creation was successful.

To demonstrate further iterations, we also have a release/v0.2.0 branch that adds the ability to deposit and withdraw funds into / from an account. This adds additional logic into the aggregate and projector microservices which were previously just handling the creation of accounts.

In order to deploy the changes from release/v0.2.0, you can create a Pull Request from the following link:

https://github.com/sgfractal/concordance-credit/compare/release/v0.2.0?expand=1

Once merged, Argo will once again sync the changes in wadm.yaml by applying them against the cluster, which in turn will prompt wadm to deploy the changes into the cluster.

As before, you will be able to view these changes by refreshing the Wormhole from before.

Finally, we have one set of changes queued up for you to complete the exercise. These changes add the ability to wire funds between bank accounts using a wire transfer process manager.

Release v0.3.0 introduces many new events so that we can wire money with a robust log of events, including exactly when money is committed to be wired and when it finishes transferring with checks along the way to ensure no account goes below the specified minimum balance.

In order to get these changes deployed, create a Pull Request for the release/v0.3.0 branch with the following link:

https://github.com/sgfractal/concordance-credit/compare/release/v0.3.0?expand=1

Once merged, Argo will take care of applying the changes to the cluster and wadm will roll out a new version of the application in response.

As before, you can refresh the Wormhole from before to see the final changes live!

That concludes the demo. We hope that this demonstration has helped illustrate how you can combine the familiar practice of GitOps with the new and emerging technology of WebAssembly!

If you would like to learn more about how wasmCloud and Cosmonic can help you realize the benefits of WebAssembly in development and production, you can connect with us at:

• Cosmonic Discord
• wasmCloud Slack