---
title: Charmhub | litmus_auth interface
description: Interfaces describe the relation between two charms. This interface shows
  opinionated, standardized interface specifications for charm relations.
url: https://charmhub.io/integrations/litmus_auth
---

# litmus\_auth

## Usage

This interface enables communication between the Litmus auth and backend
charms by primarily sharing each service’s gRPC server endpoints.

In most cases, this will be accomplished using the [litmus\_auth library](https://github.com/canonical/litmus-operators/blob/main/libs/src/litmus_libs/interfaces/litmus_auth.py), although charm developers are free to provide alternative libraries as long as they fulfill the behavioral and schematic requirements described in this document.

## Direction

This interface implements a provider/requirer pattern. The provider is the auth server and the requirer is the backend server.

Information flows back and forth: The requirer shares its gRPC server endpoint, and the provider also shares its gRPC server endpoint.

```
flowchart TD
    Requirer -- Endpoint --> Provider
    Provider -- Endpoint --> Requirer
```

## Behavior

### Provider

* Must publish its gRPC server's hostname and port.
* Must pass `insecure=True` if the gRPC server endpoint is incapable of accepting TLS connections.

### Requirer

* Must publish its gRPC server's hostname and port.
* Must pass `insecure=True` if the gRPC server endpoint is incapable of accepting TLS connections.

## Relation Data

[[Pydantic Schema]](https://github.com/canonical/charmlibs/blob/main/interfaces/litmus_auth/interface/vv0/schema.py)

### Example

A yaml/json example of a valid databag state (for the whole relation), in absence of an ingress
integration for the provider:

```
provider:
  app:
    grpc_server_host: provider.grpc.host
    grpc_server_port: 8080
    insecure: false
    version: 0
  unit:
requirer:
  app:
    grpc_server_host: requirer.grpc.host
    grpc_server_port: 3030
    insecure: false
    version: 0
  unit:
```

## Charms implementing this interface

### Providers

* [litmus-auth-k8s](https://charmhub.io/litmus-auth-k8s)

### Requirers

* [litmus-backend-k8s](https://charmhub.io/litmus-backend-k8s)

## Other charms using this interface

### Providers

### Requirers