nixos/acme: lego run whenen account is missing

nixos/modules/security/acme.nix

@@ -253,7 +253,8 @@ let
         echo '${domainHash}' > domainhash.txt
 
         # Check if we can renew
-        if [ -e 'certificates/${keyName}.key' -a -e 'certificates/${keyName}.crt' ]; then
+        # Certificates and account credentials must exist
+        if [ -e 'certificates/${keyName}.key' -a -e 'certificates/${keyName}.crt' -a "$(ls -1 accounts)" ]; then
 
           # When domains are updated, there's no need to do a full
           # Lego run, but it's likely renew won't work if days is too low.

nixos/modules/security/acme.xml

@@ -263,4 +263,28 @@ chmod 400 /var/lib/secrets/certs.secret
    ones.
   </para>
  </section>
+ <section xml:id="module-security-acme-fix-jws">
+  <title>Fixing JWS Verification error</title>
+
+  <para>
+   It is possible that your account credentials file may become corrupt and need
+   to be regnerated. In this scenario lego will produce the error <literal>JWS verification error</literal>.
+   The solution is to simply delete the associated accounts file and
+   re-run the affected service(s).
+  </para>
+
+<programlisting>
+# Find the accounts folder for the certificate
+systemctl cat acme-example.com.service | grep -Po 'accounts/[^:]*'
+export accountdir="$(!!)"
+# Move this folder to some place else
+mv /var/lib/acme/.lego/$accountdir{,.bak}
+# Recreate the folder using systemd-tmpfiles
+systemd-tmpfiles --create
+# Get a new account and reissue certificates
+# Note: Do this for all certs that share the same account email address
+systemctl start acme-example.com.service
+</programlisting>
+
+ </section>
 </chapter>