Configure logrotate

This adds a logrotate configuration for Heka when systemd is not used.
diff --git a/heka/_service.sls b/heka/_service.sls
index 535e5cb..359e716 100644
--- a/heka/_service.sls
+++ b/heka/_service.sls
@@ -53,6 +53,16 @@
   - mode: 644
   - replace: false
 
+/etc/logrotate.d/{{ service_name }}:
+  file.managed:
+  - source: salt://heka/files/heka_logrotate.conf
+  - template: jinja
+  - defaults:
+    service_name: {{ service_name }}
+  - user: root
+  - group: root
+  - mode: 644
+
 heka_{{ service_name }}_service_wrapper:
   file.managed:
   - name: /usr/local/bin/{{ service_name }}_wrapper
diff --git a/heka/files/heka_logrotate.conf b/heka/files/heka_logrotate.conf
new file mode 100644
index 0000000..2e290ad
--- /dev/null
+++ b/heka/files/heka_logrotate.conf
@@ -0,0 +1,21 @@
+/var/log/{{ service_name }}.log {
+  # Heka cannot be told to close its log file and re-open it so we need to
+  # use the copytruncate option
+  copytruncate
+  compress
+  delaycompress
+  missingok
+  notifempty
+  # logrotate allows to use only year, month, day and unix epoch
+  dateext
+  dateformat -%Y%m%d-%s
+  # number of rotated files to keep
+  rotate 10
+  # do not rotate files unless both size and time conditions are met
+  hourly
+  minsize 20M
+  # force rotate if filesize exceeded 100M
+  maxsize 100M
+  # this must map the /var/log directory group ownership
+  su root syslog
+}