initial commit

Dockerfile

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+FROM python:3.6-alpine
+
+RUN mkdir /app
+COPY my.py /app
+WORKDIR /app
+
+ENTRYPOINT ["python3", "-u", "my.py"]
+

README.md

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+Python I/O redirection with Docker example
+===
+
+Toy project experimenting how to use a Python app inside a Docker container to stream commands via STDIN
+and receive responses via STDOUT just like you would do with a local Python app.
+
+This might help in deciding how to invoke apps embedded with Docker.
+
+Local invocation
+===
+
+Just for reference, this is what I want to achieve:
+
+$ cat | python3===
+
+Toy project experimenting how to use a Python app inside a Docker container to stream commands via STDIN
+and receive responses via STDOUT just like you would do with a local Python app.
+
+Local invocation
+===
+
+Just for reference, this is what I want to achieve:
+
+    $ cat | python3 my.py 
+    1 2 3
+    6
+    10 20 30
+    60
+    ^CTraceback (most recent call last):
+      File "my.py", line 11, in <module>
+          for line in sys.stdin:
+          KeyboardInterrupt
+          my.py 
+
+Building the Docker image
+===
+
+    docker build -t mypy .
+
+Invoking it
+===
+
+    $ cat | docker run --rm -i mypy 
+    1 2 3
+    6
+    10 20 30
+    60
+    ^CTraceback (most recent call last):
+      File "my.py", line 12, in <module>
+        for line in sys.stdin:
+    KeyboardInterrupt
+

my.py

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+import sys
+
+def processLine(line):
+    return processTokens(line.split())
+
+def processTokens(tokens):
+    mysum = sum( [int(s) for s in tokens if s.isdigit()] )
+    return mysum
+
+if __name__ == "__main__":
+    for line in sys.stdin:
+        print(processLine(line))