[PATCH proxmox 2/7] acme: add retry-after header to renewal information.

[Manuel Federanko <m.federanko@proxmox.com>]

This is not yet used but makes it easier to make the ARI workflow of
the client smarter later.

Signed-off-by: Manuel Federanko <m.federanko@proxmox.com>
---
 proxmox-acme/src/async_client.rs | 19 ++++++++++++++++++-
 proxmox-acme/src/renewal.rs      |  3 +++
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/proxmox-acme/src/async_client.rs b/proxmox-acme/src/async_client.rs
index 6670bc24..c133a54e 100644
--- a/proxmox-acme/src/async_client.rs
+++ b/proxmox-acme/src/async_client.rs
@@ -360,7 +360,10 @@ impl AcmeClient {
         match Self::execute(&mut self.http_client, request, &mut self.nonce).await {
             Ok(response) => {
                 let data: crate::renewal::RenewalInformationData = response.json()?;
-                Ok(Some(crate::renewal::RenewalInformation { data }))
+                Ok(Some(crate::renewal::RenewalInformation {
+                    data,
+                    retry_after: response.retry_after,
+                }))
             }
             Err(err) => Err(err.into()),
         }
@@ -384,6 +387,7 @@ impl AcmeClient {
 struct AcmeResponse {
     body: Bytes,
     location: Option<String>,
+    retry_after: Option<String>,
     got_nonce: bool,
 }
 
@@ -470,9 +474,22 @@ impl AcmeClient {
                 })
                 .transpose()?;
 
+            let retry_after = parts
+                .headers
+                .get("Retry-After")
+                .map(|header| {
+                    header.to_str().map(str::to_owned).map_err(|err| {
+                        Error::Client(format!(
+                            "received invalid retry-after header from ACME server: {err}"
+                        ))
+                    })
+                })
+                .transpose()?;
+
             return Ok(AcmeResponse {
                 body,
                 location,
+                retry_after,
                 got_nonce,
             });
         }
diff --git a/proxmox-acme/src/renewal.rs b/proxmox-acme/src/renewal.rs
index eb4ff96a..6454affc 100644
--- a/proxmox-acme/src/renewal.rs
+++ b/proxmox-acme/src/renewal.rs
@@ -30,4 +30,7 @@ pub struct RenewalInformationData {
 pub struct RenewalInformation {
     /// the actual response of the acme server
     pub data: RenewalInformationData,
+
+    /// when to check the renewal endpoint again
+    pub retry_after: Option<String>,
 }
-- 
2.47.3