Module solvers 

ACME challenge solvers.

This module provides trait-based abstractions and concrete implementations for solving ACME challenges (HTTP-01, TLS-ALPN-01, DNS-01) as well as a distributed solver wrapper for clustered deployments.

Challenge types

Solver	Port	How it works
Http01Solver	80	Serves key_auth at /.well-known/acme-challenge/{token}
TlsAlpn01Solver	443	Presents a self-signed cert with the acmeIdentifier extension via acme-tls/1 ALPN
Dns01Solver	n/a	Creates a _acme-challenge TXT record via a DnsProvider

Distributed deployments

In a cluster, wrap any solver with DistributedSolver so that challenge data is persisted to shared Storage. This allows any cluster member to respond to the CA’s validation request, not just the instance that initiated the certificate order.

Structs

DistributedSolver

Wraps any Solver for clustered / distributed deployments.

Dns01Solver

Solves ACME DNS-01 challenges by creating a TXT record via a DnsProvider implementation and optionally waiting for propagation.

Http01Solver

Solves ACME HTTP-01 challenges by serving the key authorization string at GET /.well-known/acme-challenge/{token} on a simple HTTP server.

TlsAlpn01Solver

Solves ACME TLS-ALPN-01 challenges by presenting a self-signed certificate with the acmeIdentifier extension during the TLS handshake, negotiated via the acme-tls/1 ALPN protocol (RFC 8737).

Traits

DnsProvider

Abstraction over a DNS provider that can create and delete TXT records.

Solver

An ACME challenge solver.

Functions

get_active_challenge

Look up the key authorization for an active challenge by its identifier.