Add Docker development workflow

Dockerfile

@@ -0,0 +1,19 @@
+FROM pataquets/collectd-python-pip
+
+RUN \
+  apt-get update && \
+  DEBIAN_FRONTEND=noninteractive \
+    apt-get -y install libmysqlclient-dev \
+  && \
+  apt-get clean && \
+  rm -rf /var/lib/apt/lists/*
+
+RUN pip install --no-cache mysqlclient
+
+RUN \
+  ln -vs /etc/collectd/conf-available/write-csv-stdout.conf \
+    /etc/collectd/conf.d/ \
+  && \
+  nl \
+    /etc/collectd/collectd.conf \
+    /etc/collectd/conf.d/*

README.md

@@ -322,5 +322,8 @@ For versions of MySQL with support for it and where enabled, `INFORMATION_SCHEMA
     response_time_total.14
     response_time_count.14
 
+## Development
+A Docker Compose manifest with a stack for testing and development is provided. Just issue ```docker-compose up --build``` to start it. See ```docker-compose.yml``` and ```mysql.conf``` files for configuration details.
+
 ## License
 MIT (http://www.opensource.org/licenses/mit-license.php)

docker-compose.yml

@@ -0,0 +1,28 @@
+# Docker Compose development manifest
+# This manifest spins up a MariaDB/MySQL server container and builds a
+# collectd+python image with all required runtime dependencies and starts
+# a collectd container linked to the database container to allow testing.
+
+# By default, MariaDB/MySQL port is not exposed to the development host,
+# since collectd connects using a hostname defined via container link.
+mysql:
+  image: mariadb
+  environment:
+    - MYSQL_ALLOW_EMPTY_PASSWORD=yes
+#    - MYSQL_ROOT_PASSWORD=root
+#    - MYSQL_USER=collectd
+#    - MYSQL_PASSWORD=collectd
+#  ports:
+#    - "3306:3306"
+
+# Collectd service mounts both Python code and plugin configuration from
+# current development directory.
+# The parent image used for the build just uses collectd's built in CSV
+# plugin with output to stdout for debugging.
+collectd:
+  build: .
+  links:
+    - mysql
+  volumes:
+    - ./mysql.py:/opt/collectd/lib/collectd/plugins/python/mysql.py:ro
+    - ./mysql.conf:/etc/collectd/conf.d/mysql.conf:ro

mysql.conf

@@ -0,0 +1,18 @@
+<LoadPlugin python>
+  Globals true
+</LoadPlugin>
+<Plugin python>
+  ModulePath "/opt/collectd/lib/collectd/plugins/python/"
+  # Verbose true
+</Plugin>
+<Plugin python>
+  Import mysql
+  <Module mysql>
+    Host "mysql"
+    # Port 3306
+    # User "root" # (default: root)
+    # Password "xxxx" # (default: empty)
+    # HeartbeatTable "percona.heartbeat" # (if using pt-heartbeat to track slave lag)
+    # Verbose false # (default: false)
+  </Module>
+</Plugin>