Add runHydra shell

runHyda automatically starts hydra and postgres:

```
$ nix-shell -A runHydra
```

The shell receives hydra from the working copy as buildInput.
Running hydra, queue-runner, evaluator and postgres is managed
by foreman (https://github.com/ddollar/foreman) and configured
in `Procfile`.

.gitignore

@@ -3,6 +3,7 @@
 Makefile
 Makefile.in
 .deps
+.hydra-data
 /config.guess
 /config.log
 /config.status

Procfile

@@ -0,0 +1,4 @@
+hydra-server: ./scripts/start-hydra.sh
+hydra-queue-runner: ./scripts/start-queue-runner.sh
+hydra-evaluator: ./scripts/start-evaluator.sh
+postgres: ./scripts/start-postgres.sh

flake.nix

@@ -104,13 +104,16 @@
             [ makeWrapper autoconf automake libtool unzip nukeReferences pkgconfig libpqxx
               gitAndTools.topGit mercurial darcs subversion bazaar openssl bzip2 libxslt
               perlDeps perl final.nix
-              postgresql95 # for running the tests
               boost
               (if lib.versionAtLeast lib.version "20.03pre"
                then nlohmann_json
                else nlohmann_json.override { multipleHeaders = true; })
             ];
 
+          checkInputs = [
+            postgresql95
+          ];
+
           hydraPath = lib.makeBinPath (
             [ subversion openssh final.nix coreutils findutils pixz
               gzip bzip2 lzma gnutar unzip git gitAndTools.topGit mercurial darcs gnused bazaar
@@ -290,6 +293,8 @@
         nixpkgs.overlays = [ self.overlay nix.overlay ];
       };
 
+      runHydra = pkgs.callPackage ./run-hydra.nix {};
+
       nixosModules.hydraTest = {
         imports = [ self.nixosModules.hydra ];
 

run-hydra.nix

@@ -0,0 +1,16 @@
+{ foreman, mkShell, hydra, netcat, postgresql95 }:
+{ doCheck ? true }:
+mkShell {
+  buildInputs = [
+    foreman (hydra.overrideAttrs (_: { inherit doCheck; })) netcat postgresql95
+  ];
+
+  shellHook = ''
+    export HYDRA_HOME="src/"
+    mkdir -p .hydra-data
+    export HYDRA_DATA="$(pwd)/.hydra-data"
+    export HYDRA_DBI='dbi:Pg:dbname=hydra;host=localhost;'
+
+    exec foreman start
+  '';
+}

scripts/start-evaluator.sh

@@ -0,0 +1,6 @@
+#!/bin/sh
+
+# wait for hydra-server to listen
+while ! nc -z localhost 3000; do sleep 1; done
+
+exec hydra-evaluator

scripts/start-hydra.sh

@@ -0,0 +1,11 @@
+#!/bin/sh
+
+# wait for postgresql to listen
+while ! nc -z localhost 5432; do sleep 1; done
+
+createdb -h $(pwd)/.hydra-data/postgres hydra
+
+hydra-init
+hydra-create-user alice --password foobar --role admin
+
+exec hydra-server

scripts/start-postgres.sh

@@ -0,0 +1,4 @@
+#!/bin/sh
+
+initdb ./.hydra-data/postgres
+exec postgres -D ./.hydra-data/postgres -k $(pwd)/.hydra-data/postgres

scripts/start-queue-runner.sh

@@ -0,0 +1,6 @@
+#!/bin/sh
+
+# wait until hydra is listening on port 3000
+while ! nc -z localhost 3000; do sleep 1; done
+
+hydra-queue-runner