Ensured entrypoint for python

Author: ByteMeDirk

Dockerfile

@@ -1,21 +1,19 @@
-FROM ubuntu:18.04
+FROM ubuntu:18.04 as pyspark
 
 ENV SPARK_VERSION=3.1.2
 ENV HADOOP_VERSION=2.7
 ENV JAVA_HOME /usr/lib/jvm/java-8-openjdk-amd64/
 
-WORKDIR /app
-
 COPY requirements.txt .
+
+# Install OpenJDK-8, Hadoop, & PySpark 3
 RUN apt-get update \
-    && apt-get install -y python3 python3-pip wget software-properties-common openjdk-8-jdk \
+    && apt-get install -y python3.8 python3-pip wget software-properties-common openjdk-8-jdk \
     && export JAVA_HOME \
     && pip3 install --upgrade pip \
-    && pip3 install --no-cache -r requirements.txt \
+    && pip3 install --no-cache-dir -r requirements.txt \
     && wget --no-verbose http://apache.mirror.iphh.net/spark/spark-${SPARK_VERSION}/spark-${SPARK_VERSION}-bin-hadoop${HADOOP_VERSION}.tgz \
     && tar -xvzf spark-${SPARK_VERSION}-bin-hadoop${HADOOP_VERSION}.tgz \
     && mv spark-${SPARK_VERSION}-bin-hadoop${HADOOP_VERSION} spark \
     && rm spark-${SPARK_VERSION}-bin-hadoop${HADOOP_VERSION}.tgz \
-    && apt-get remove -y curl bzip2  \
-    && apt-get autoremove -y  \
     && apt-get clean

README.md

@@ -21,13 +21,29 @@ The docker image may assume local AWS configurations and secrets on run for spec
 docker run --rm=true -v ~/.aws:/root/.aws <etc...>
 ```
 
-This image can be extended to run any PySpark .py script using python3 or spark-submit.
+This image can be extended to run any PySpark .py script using `python3`.
 
+## Example
+Set up your local docker container that will run your scripts, 
+in our case it could be `scripts/main.py` and one could set up the data in `data/*`:
 ```docker
 FROM dirkscgm/pyspark3:latest
 
 WORKDIR /app
+
 COPY scripts/* scripts/
+COPY data/* data/
+
+ENTRYPOINT ["python3"]
+CMD ["scripts/main.py"]
+```
+
+Build the local image:
+```shell
+docker build -t pyspark3 .
+```
 
-ENTRYSCRIPT ["python3", "scripts/main.py"]
-```
+Run the container with the CMD set to the main entrypoint of the spark application:
+```shell
+docker run --rm=true pyspark3
+```