Explanation

The following explanations provide context and clarification on key topics related to the use and configuration of web app frameworks.

12-factor app principles

The glue point of the 12-factor framework support in Rockcraft and Charmcraft is the 12-factor methodology. The 12-Factor methodology is a set of best practices for building modern, scalable, and maintainable web applications. By following these principles, you can easily create a rock (OCI image) and a charm (software operator) for your web app that can take advantage of the full Juju ecosystem.

Learn more about the components involved and how the principles are applied in the following pages:

12-factor ecosystem

The native 12-factor framework support in Rockcraft and Charmcraft provides an opinionated way to easily integrate your web application into the Juju ecosystem. The Juju ecosystem provides a multitude of curated software operators for your observability stack, database, SSO, and many more and allows their deployment and lifecycle management on metal, on VMs, on K8s and on cloud providers (see substrates).

That way, the 12-factor framework support in Rockcraft and Charmcraft offers a fully fledged Platform as a Service that streamlines managing the infrastructure, whether on premises or on cloud, at any scale, and allows developers to focus on their core competences instead of a complex software stack.

12-factor app charm

The software operator built with Charmcraft containerizes the web app workload so that you can deploy, configure, and integrate your web app in the Juju ecosystem. The following page provides an overview of the architecture, components, and source code.

Development and operations

        flowchart TD
%% -- Styling Classes --
classDef nodeBox fill:#fff,stroke:#666,stroke-width:2px,color:#333,rx:5,ry:5,text-align:center;
classDef groupContainer fill:none,stroke:#7c4dff,stroke-width:2px,stroke-dasharray: 5 5,color:#333,font-size:12px;

%% -- Main Flow Styling --
linkStyle default stroke:#7c4dff,stroke-width:2px,fill:none;

%% -- Phase 1 --
subgraph P1 ["CODE"]
    direction TB
    Node1["Source:<br/>12-factor web app"]:::nodeBox
end

%% -- Phase 2 --
subgraph P2 ["BUILD + TEST"]
    direction TB
    Node2["Container:<br/>12-factor app rock"]:::nodeBox
    Node3["Software operator:<br/>12-factor app charm"]:::nodeBox
end

%% -- Phase 3 --
subgraph P3 ["RELEASE"]
    direction TB
    Node4["Published:<br/>12-factor app rock<br/>and charm in the<br/>Charmhub store"]:::nodeBox
end

%% -- Phase 4 --
subgraph P4 ["DEPLOY + OPERATE"]
    direction LR
    Node5["Production:<br/>12-factor app deployed<br/>to end users"]:::nodeBox
    Node6["Day 1 Operations:<br/>Integrate with database, ingress, SSO, etc."]:::nodeBox

    %% Internal Link (Grey)
    Node5 --> Node6
end

%% -- Phase 5 --
subgraph P5 ["MONITOR"]
    direction TB
    Node7["Observe: <br/> Track and monitor<br/>with COS"]:::nodeBox
end

%% -- Connections --
%% Connect Source to the first item in Build
Node1 --> Node2
Node1 --> Node3

%% Connect both Build items to Release
Node2 --> Node4
Node3 --> Node4

%% Connect Release to Deploy
Node4 --> Node5

%% Connect Deploy to Monitor
Node6 --> Node7

%% -- Apply Group Styles --
class P1,P2,P3,P4,P5 groupContainer

The diagram above shows the 12-factor tooling in the context of the development and operations lifecycle. The developer creates the app, uses Rockcraft and Charmcraft to build a container image and software operator, publishes the contents to the Charmhub store, and deploys the app to a Kubernetes cloud using Juju. The charming ecosystem provides everything needed for operating the charm, including databases, ingresses, and more.