Allow $site_path/secure.config to overlay $site_path/gerrit.config

The secure configuration file can be used to store only passwords,
or other data which must be node specific and cannot otherwise be
shared.  This makes it easier to check gerrit.config into an SCM
and track changes on it, without leaking key account information.

Bug: issue 325
Change-Id: Iae5fa5ff853d116f2957fffcf3820e63bb830fd5
Signed-off-by: Shawn O. Pearce <sop@google.com>

Documentation/config-gerrit.txt

@@ -1127,6 +1127,30 @@ If not set, Gerrit generates this as "gerrit@`hostname`", where
 By default, not set, generating the value at startup.
 
 
+File `secure.config`
+--------------------
+The optional file `'$site_path'/secure.config` overrides (or
+supplements) the settings supplied by `'$site_path'/gerrit.config`.
+The file should be readable only by the daemon process and can be
+used to contain private configuration entries that wouldn't normally
+be exposed to everyone.
+
+Sample `secure.config`:
+----
+[database]
+	username = webuser
+	password = s3kr3t
+
+[ldap]
+	password = l3tm3srch
+
+[httpd]
+	sslKeyPassword = g3rr1t
+
+[sendemail]
+	smtpPass = sp@m
+----
+
 File `replication.config`
 -------------------------
 

gerrit-server/src/main/java/com/google/gerrit/server/config/GerritServerConfigProvider.java

@@ -41,11 +41,13 @@ class GerritServerConfigProvider implements Provider<Config> {
 
   @Override
   public Config get() {
-    final File cfgPath = new File(sitePath, "gerrit.config");
-    final FileBasedConfig cfg = new FileBasedConfig(cfgPath);
+    final File gerrit_config = new File(sitePath, "gerrit.config");
+    final File secure_config = new File(sitePath, "secure.config");
+
+    FileBasedConfig cfg = new FileBasedConfig(gerrit_config);
 
     if (!cfg.getFile().exists()) {
-      log.info("No " + cfgPath.getAbsolutePath() + "; assuming defaults");
+      log.info("No " + gerrit_config.getAbsolutePath() + "; assuming defaults");
       return cfg;
     }
 
@@ -57,6 +59,17 @@ class GerritServerConfigProvider implements Provider<Config> {
       throw new ProvisionException(e.getMessage(), e);
     }
 
+    if (secure_config.exists()) {
+      cfg = new FileBasedConfig(cfg, secure_config);
+      try {
+        cfg.load();
+      } catch (IOException e) {
+        throw new ProvisionException(e.getMessage(), e);
+      } catch (ConfigInvalidException e) {
+        throw new ProvisionException(e.getMessage(), e);
+      }
+    }
+
     return cfg;
   }
 }