Create account key pair at startup

If several certificates uses the same account and this account doesn't
exists yet, they will both try to create it, resulting in a race
condition. This commit solves the problem by creating the account key
pair at startup. Account creation on the endpoint is not subject to a
race condition since the request does not differ from the one used to
retrieve the account id.
Fix #3

acmed/src/acme_proto.rs

@@ -10,7 +10,7 @@ use acme_common::error::Error;
 use serde_json::json;
 use std::fmt;
 
-mod account;
+pub mod account;
 mod certificate;
 mod http;
 pub mod structs;

acmed/src/acme_proto/account.rs

@@ -22,17 +22,7 @@ impl AccountManager {
         root_certs: &[String],
     ) -> Result<(Self, String), Error> {
         // TODO: store the key id (account url)
-        let key_pair = if storage::account_files_exists(cert) {
-            // TODO: check if the keys are suitable for the specified signature algorithm
-            // and, if not, initiate a key rollover.
-            storage::get_account_keypair(cert)?
-        } else {
-            // TODO: allow to change the signature algo
-            let sign_alg = SignatureAlgorithm::from_str(crate::DEFAULT_JWS_SIGN_ALGO)?;
-            let key_pair = sign_alg.gen_key_pair()?;
-            storage::set_account_keypair(cert, &key_pair)?;
-            key_pair
-        };
+        let key_pair = storage::get_account_keypair(cert)?;
         let account = Account::new(cert);
         let account = serde_json::to_string(&account)?;
         let data_builder =
@@ -53,3 +43,20 @@ impl AccountManager {
         Ok((ac, nonce))
     }
 }
+
+pub fn init_account(cert: &Certificate) -> Result<(), Error> {
+    if !storage::account_files_exists(cert) {
+        // TODO: allow to change the signature algo
+        let sign_alg = SignatureAlgorithm::from_str(crate::DEFAULT_JWS_SIGN_ALGO)?;
+        let key_pair = sign_alg.gen_key_pair()?;
+        storage::set_account_keypair(cert, &key_pair)?;
+        let msg = format!("Account {} created.", &cert.account.name);
+        cert.info(&msg)
+    } else {
+        // TODO: check if the keys are suitable for the specified signature algorithm
+        // and, if not, initiate a key rollover.
+        let msg = format!("Account {} already exists.", &cert.account.name);
+        cert.debug(&msg)
+    }
+    Ok(())
+}

acmed/src/main_event_loop.rs

@@ -1,3 +1,4 @@
+use crate::acme_proto::account::init_account;
 use crate::acme_proto::request_certificate;
 use crate::certificate::Certificate;
 use crate::config;
@@ -67,6 +68,7 @@ impl MainEventLoop {
                 env: crt.env.to_owned(),
                 id: i + 1,
             };
+            init_account(&cert)?;
             certs.push(cert);
         }