2 files changed, 57 insertions, 5 deletions

diff --git a/nixos/modules/services/web-servers/nginx/default.nix b/nixos/modules/services/web-servers/nginx/default.nix
index 508398f03ace..6c733f093ba8 100644
--- a/nixos/modules/services/web-servers/nginx/default.nix
+++ b/nixos/modules/services/web-servers/nginx/default.nix
@@ -46,7 +46,7 @@ let
 
   configFile = pkgs.writeText "nginx.conf" ''
     user ${cfg.user} ${cfg.group};
-    error_log stderr;
+    error_log ${cfg.logError};
     daemon off;
 
     ${cfg.config}
@@ -341,6 +341,35 @@ in
         ";
       };
 
+      logError = mkOption {
+        default = "stderr";
+        description = "
+          Configures logging.
+          The first parameter defines a file that will store the log. The
+          special value stderr selects the standard error file. Logging to
+          syslog can be configured by specifying the “syslog:” prefix.
+          The second parameter determines the level of logging, and can be
+          one of the following: debug, info, notice, warn, error, crit,
+          alert, or emerg. Log levels above are listed in the order of
+          increasing severity. Setting a certain log level will cause all
+          messages of the specified and more severe log levels to be logged.
+          If this parameter is omitted then error is used.
+        ";
+      };
+
+      preStart =  mkOption {
+        type = types.lines;
+        default = ''
+          test -d ${cfg.stateDir}/logs || mkdir -m 750 -p ${cfg.stateDir}/logs  
+          test `stat -c %a ${cfg.stateDir}` = "750" || chmod 750 ${cfg.stateDir}
+          test `stat -c %a ${cfg.stateDir}/logs` = "750" || chmod 750 ${cfg.stateDir}/logs
+          chown -R ${cfg.user}:${cfg.group} ${cfg.stateDir}
+        '';
+        description = "
+          Shell commands executed before the service's nginx is started.
+        ";
+      };
+
       config = mkOption {
         default = "";
         description = "
@@ -608,9 +637,7 @@ in
       stopIfChanged = false;
       preStart =
         ''
-        mkdir -p ${cfg.stateDir}/logs
-        chmod 700 ${cfg.stateDir}
-        chown -R ${cfg.user}:${cfg.group} ${cfg.stateDir}
+        ${cfg.preStart}
         ${cfg.package}/bin/nginx -c ${configFile} -p ${cfg.stateDir} -t
         '';
       serviceConfig = {
diff --git a/nixos/modules/services/web-servers/tomcat.nix b/nixos/modules/services/web-servers/tomcat.nix
index be54e9255c78..68261c50324d 100644
--- a/nixos/modules/services/web-servers/tomcat.nix
+++ b/nixos/modules/services/web-servers/tomcat.nix
@@ -31,10 +31,26 @@ in
         '';
       };
 
+      purifyOnStart = mkOption {
+        type = types.bool;
+        default = false;
+        description = ''
+          On startup, the `baseDir` directory is populated with various files,
+          subdirectories and symlinks. If this option is enabled, these items
+          (except for the `logs` and `work` subdirectories) are first removed.
+          This prevents interference from remainders of an old configuration
+          (libraries, webapps, etc.), so it's recommended to enable this option.
+        '';
+      };
+
       baseDir = mkOption {
         type = lib.types.path;
         default = "/var/tomcat";
-        description = "Location where Tomcat stores configuration files, webapplications and logfiles";
+        description = ''
+          Location where Tomcat stores configuration files, web applications
+          and logfiles. Note that it is partially cleared on each service startup
+          if `purifyOnStart` is enabled.
+        '';
       };
 
       logDirs = mkOption {
@@ -197,6 +213,15 @@ in
       after = [ "network.target" ];
 
       preStart = ''
+        ${lib.optionalString cfg.purifyOnStart ''
+          # Delete most directories/symlinks we create from the existing base directory,
+          # to get rid of remainders of an old configuration.
+          # The list of directories to delete is taken from the "mkdir" command below,
+          # excluding "logs" (because logs are valuable) and "work" (because normally
+          # session files are there), and additionally including "bin".
+          rm -rf ${cfg.baseDir}/{conf,virtualhosts,temp,lib,shared/lib,webapps,bin}
+        ''}
+
         # Create the base directory
         mkdir -p \
           ${cfg.baseDir}/{conf,virtualhosts,logs,temp,lib,shared/lib,webapps,work}