Configures an ACME (RFC 8555) client, e.g. to retrieve TLS certificates from Let's Encrypt.

To store the key material and certificates, you can use the local file system or your Kubernetes cluster.

To use ACME:

1. Register your domain and point the DNS record to your server(s) runnig Membrane.
2. Let Membrane listen on port 80 and use the <acmeHttpChallenge /> (see below).
3. Let Membrane listen on port 443 and use <ssl><acme .../><ssl> (see below). Here, you have to configure where Membrane will store the keys and certificates.

<acme directoryUrl="[acme server URL]"
contacts="mailto:webmaster@example.com"
termsOfServiceAgreed="[true,false]">
	[storage]
	[validation]
</acme>

<serviceProxy port="80">
  <acmeHttpChallenge />
    <groovy>
      exc.setResponse(Response.ok("here").build());
      RETURN
    </groovy>
</serviceProxy>

<serviceProxy host="test.example.com" port="443">
  <ssl>
    <acme
      directoryUrl="https://acme-staging-v02.api.letsencrypt.org/directory"
      contacts="mailto:webmaster@example.com"
      termsOfServiceAgreed="true">
      <fileStorage dir="C:\tmp" />
    </acme>
  </ssl>
    ...
</serviceProxy>

<serviceProxy host="test.example.com" port="443">
  <ssl>
    <acme
      directoryUrl="https://acme-staging-v02.api.letsencrypt.org/directory"
      contacts="mailto:webmaster@example.com"
      termsOfServiceAgreed="true"&gt;
  <kubernetesStorage namespace="membrane"
      masterLease="membrane" accountSecret="acme-account" prefix="acme-" />
    </acme>
  </ssl>
    ...
</serviceProxy>