nix: add user doc and pkg fixes

- Add user doc for how to use with nix/nixos

- fix potential collisions in packages if both are installed via
  `nix-env`

build.sbt

@@ -314,7 +314,8 @@ val microsite = project.in(file("modules/microsite")).
     fork in run := true,
     micrositeCompilingDocsTool := WithMdoc,
     mdocVariables := Map(
-      "VERSION" -> version.value
+      "VERSION" -> version.value,
+      "PVERSION" -> version.value.replace('.', '_')
     ),
     Compile/resourceGenerators += Def.task {
       val conf1 = (resourceDirectory in (restserver, Compile)).value / "reference.conf"

modules/microsite/docs/doc/nix.md

@@ -0,0 +1,129 @@
+---
+layout: docs
+title: Nix/NixOS
+permalink: doc/nix
+---
+
+# {{ page.title }}
+
+## Install via Nix
+
+Docspell can be installed via the [nix](https://nixos.org/nix) package
+manager, which is available for Linux and OSX. Docspell is currently not
+part of the [nixpkgs collection](https://nixos.org/nixpkgs/), but you
+can use the derivation from this repository. This is sometimes
+referred to as [import from
+derivation](https://nixos.wiki/wiki/Import_From_Derivation).
+
+For example, the `builtins.fetchTarball` function can be used to
+retrieve the files; then import the `release.nix` file:
+
+``` nix
+let
+  docspellsrc = builtins.fetchTarball "https://github.com/eikek/docspell/archive/master.tar.gz";
+in
+import "${docspellsrc}/nix/release.nix";
+```
+
+This creates a set containing a function for creating a derivation for
+docspell. This then needs to be called like other custom packages. For
+example, in your `~/.nixpkgs/config.nix` you could write this:
+
+``` nix
+let
+  docspellsrc = builtins.fetchTarball "https://github.com/eikek/docspell/archive/master.tar.gz";
+  docspell = import "${docspellsrc}/nix/release.nix";
+in
+{ packageOverrides = pkgs:
+   let
+     callPackage = pkgs.lib.callPackageWith(custom // pkgs);
+     custom = {
+       docspell = callPackage docspell.currentPkg {};
+     };
+   in custom;
+}
+```
+
+The `docspell` custom package is again a set that contains derivations
+for all 3 installable docspell programs: the restserver, joex and the
+tools.
+
+Then you can install docspell via `nix-shell` or `nix-env`, for example:
+
+``` bash
+$ nix-env -iA nixpkgs.docspell.server nixpkgs.docspell.joex nixpkgs.docspell.tools
+```
+
+You may need to replace `nixpkgs` with `nixos` when you're on NixOS.
+
+The expression `docspell.currentPkg` refers to the most current release
+of Docspell. So even if you use the tarball of the current master
+branch, the `release.nix` file only contains derivations for releases.
+The expression `docspell.currentPkg` is a shortcut for selecting the
+most current release. For example it translates to `docspell.pkg
+docspell.cfg.v@PVERSION@` – if the current version is `@VERSION@`.
+
+
+## Docspell as a service on NixOS
+
+If you are running [NixOS](https://nixos.org), there is a module
+definition for installing Docspell as a service using systemd.
+
+There are the following modules provided:
+
+- restserver
+- joex
+- consumedir
+
+The `consumedir` module defines a systemd unit that starts the
+`consumedir.sh` script to watch one or more directories for new files.
+
+You need to import the `release.nix` file as described above in your
+`configuration.nix` and then append the docspell module to your list of
+modules. Here is an example:
+
+```nix
+{ config, pkgs, ... }:
+let
+  docspellsrc = builtins.fetchTarball "https://github.com/eikek/docspell/archive/master.tar.gz";
+  docspell = import "${docspellsrc}/nix/release.nix";
+in
+{
+  imports = [ mymodule1 mymodule2 ] ++ docspell.modules;
+
+  nixpkgs = {
+    config = {
+      packageOverrides = pkgs:
+        let
+          callPackage = pkgs.lib.callPackageWith(custom // pkgs);
+          custom = {
+            docspell = callPackage docspell.currentPkg {};
+          };
+        in custom;
+    };
+  };
+
+  services.docspell-restserver = {
+    enable = true;
+    base-url = "http://docspelltest:7880";
+    # ... more settings here
+  };
+  services.docspell-joex = {
+    enable = true;
+    base-url = "http://docspelltexst:7878";
+    # ... more settings here
+  };
+  services.docspell-consumedir = {
+    enable = true;
+    watchDirs = ["/tmp/test"];
+    urls = ["http://localhost:7880/api/v1/open/upload/item/the-source-id"];
+  };
+
+  ...
+}
+
+```
+
+Please see the `nix/module-server.nix` and `nix/module-joex.nix` files
+for the set of options. The nixos options are modelled after the
+default configuration file.

modules/microsite/src/main/resources/microsite/data/menu.yml

@@ -18,6 +18,9 @@ options:
      - title: Installation
        url: doc/install.html
 
+     - title: Nix/NixOS
+       url: doc/nix
+
      - title: Configuring
        url: doc/configure.html
 

nix/configuration-test.nix

@@ -39,7 +39,11 @@ in
     urls = ["http://localhost:7880/api/v1/open/upload/item/blabla"];
   };
 
-  environment.systemPackages = [ pkgs.docspell.tools pkgs.jq ];
+  environment.systemPackages =
+    [ pkgs.docspell.tools
+      pkgs.docspell.server
+      pkgs.docspell.joex pkgs.jq
+    ];
 
   services.xserver = {
     enable = false;

nix/pkg.nix

@@ -17,11 +17,11 @@ in
     buildPhase = "true";
 
     installPhase = ''
-      mkdir -p $out/{bin,program}
-      cp -R * $out/program/
+      mkdir -p $out/{bin,docspell-restserver-${cfg.version}}
+      cp -R * $out/docspell-restserver-${cfg.version}/
       cat > $out/bin/docspell-restserver <<-EOF
       #!${bash}/bin/bash
-      $out/program/bin/docspell-restserver -java-home ${jre8_headless} "\$@"
+      $out/docspell-restserver-${cfg.version}/bin/docspell-restserver -java-home ${jre8_headless} "\$@"
       EOF
       chmod 755 $out/bin/docspell-restserver
     '';
@@ -39,11 +39,11 @@ in
     buildPhase = "true";
 
     installPhase = ''
-      mkdir -p $out/{bin,program}
-      cp -R * $out/program/
+      mkdir -p $out/{bin,docspell-joex-${cfg.version}}
+      cp -R * $out/docspell-joex-${cfg.version}/
       cat > $out/bin/docspell-joex <<-EOF
       #!${bash}/bin/bash
-      $out/program/bin/docspell-joex -java-home ${jre8_headless} "\$@"
+      $out/docspell-joex-${cfg.version}/bin/docspell-joex -java-home ${jre8_headless} "\$@"
       EOF
       chmod 755 $out/bin/docspell-joex
     '';