Add a template for a simple, generic memcached service

templates/task.memcached

@@ -0,0 +1,48 @@
+[[- /* vim: syntax=hcl
+ This is a generic, small and reusable memcached task */ -]]
+
+    # Local memcached instance
+    task "memcached" {
+      driver = "docker"
+      user   = 11211
+
+      lifecycle {
+        hook    = "prestart"
+        sidecar = true
+      }
+
+      config {
+        image           = "memcached:alpine"
+        readonly_rootfs = true
+        force_pull      = true
+        entrypoint      = ["/local/memcached"]
+      }
+
+      template {
+        data =<<_EOT
+#!/bin/sh
+
+set -eu
+exec memcached -l 127.0.0.1 -p 11211 -m {{ env "NOMAD_MEMORY_LIMIT" | parseInt | subtract 5 }}
+_EOT
+        destination = "local/memcached"
+        perms       = 755
+      }
+
+      resources {
+[[- if and (has . "resources") (has .resources "cpu") ]]
+        cpu = [[ .resources.cpu ]]
+[[- else ]]
+        cpu = 10
+[[- end ]]
+[[- if and (has . "resources") (has .resources "memory") ]]
+        memory = [[ .resources.memory ]]
+[[- else ]]
+        memory = 20
+[[- end ]]
+[[- if and (has . "resources") (has .resources "memory_max") ]]
+        memory_max = [[ .resources.memory_max ]]
+[[- end ]]
+      }
+    }
+