private SamlIdentityProviderConfig validateAndGetIdPConfig(LogoutRequest logoutRequest,
                                                               String endpointUri) {
        final String issuer = logoutRequest.getIssuer().getValue();
        if (issuer == null) {
            throw new InvalidSamlRequestException("no issuer found from the logout request: " +
                                                  logoutRequest.getID());
        }
        if (!endpointUri.equals(logoutRequest.getDestination())) {
            throw new InvalidSamlRequestException("unexpected destination: " + logoutRequest.getDestination());
        }
        final SamlIdentityProviderConfig config = idpConfigs.get(issuer);
        if (config == null) {
            throw new InvalidSamlRequestException("unexpected identity provider: " + issuer);
        }
        return config;
    }
A service which receives a single logout request from an identity provider in order to perform a global
logout.
saml/src/main/java/com/linecorp/armeria/server/saml/SamlSingleLogoutFunction.java