Setup a Docker-based dev environment

Dockerfile-dev

@@ -0,0 +1,8 @@
+FROM python:3.6-alpine
+
+# Install dependencies
+COPY requirements.txt /prometheus-pgbouncer-exporter/
+RUN  apk add --update --no-cache postgresql-dev gcc musl-dev && \
+     pip install -r /prometheus-pgbouncer-exporter/requirements.txt
+
+WORKDIR /prometheus-pgbouncer-exporter

README.md

@@ -117,19 +117,27 @@ pgbouncers:
 The configuration file supports environment variables replacement. If you use the syntax `$(NAME)` in any setting value, it gets replaced by the content of `NAME` environment variable or left untouched if the `NAME` environment variable does not exist.
 
 
-## Contributions
+## How to contribute
 
-### Run locally
+Run the **development environment**:
 
-`python3 -m prometheus_pgbouncer_exporter.cli --config ./config.yml`
+```
+docker-compose build && docker-compose run dev
+```
 
-### Run tests
+Then inside the container:
 
-`python3 -m unittest`
+```
+# Run tests
+python -m unittest
 
-### Ensure the code is PEP 8 compliant
+# Run exporter
+python -m prometheus_pgbouncer_exporter.cli --config ./config.yml
+
+# Run linter
+pycodestyle --max-line-length=300 prometheus_pgbouncer_exporter/*.py
+```
 
-`pycodestyle --max-line-length=300 prometheus_pgbouncer_exporter/*.py`
 
 ### How to publish a new version
 

docker-compose.yml

@@ -0,0 +1,10 @@
+version: "3"
+
+services:
+  dev:
+    build:
+      context:    .
+      dockerfile: Dockerfile-dev
+    command: [ "sh" ]
+    volumes:
+      - .:/prometheus-pgbouncer-exporter:delegated