actix-web-middleware-opa

Open Policy Agent (openpolicyagent/OPA) middleware for actix-web applications.

This middleware performs a policy check against an Open Policy Agent instance for incoming HTTP requests.

Both the policy check request and response are generic.

Flow

Example

Take the following request :

curl -XGET -H 'Authorization: Bearer 123123123' http://localhost:8080/order/item/1

This will need to be translated to a JSON call to OPA :

json { "input" : { "token" : "123123123", "method" : "GET", "path" : ["order", "item", "1"] } }

We represent this as two Rust structs which implement Serialize,

```rust

[derive(Serialize)]

struct PolicyRequest { input: PolicyRequestInput, }

[derive(Serialize)]

struct PolicyRequestInput { token: String, method: String, path: Vec, } ```

json { "result" : { "allow" : true } }

```rust #[derive(Serialize)] struct PolicyRequest { name: String, }

impl<S> OPARequest<S> for PolicyRequest {
    fn from_http_request(_req: &HttpRequest<S>) -> Result<Self, String> {
        Ok(PolicyRequest {
            name: "Sam".to_string(),
        })
    }
}

#[derive(Deserialize)]
struct PolicyResponse {
    result: OPAResult,
}

#[derive(Deserialize)]
struct OPAResult {
    allow: bool,
}

impl OPAResponse for PolicyResponse {
    fn allowed(&self) -> bool {
        self.result.allow
    }
}

type VerifierMiddleware = PolicyVerifier<PolicyRequest, PolicyResponse>;

```