Created Dockerfile and fixed typo fix in main flask app

.python-version

@@ -0,0 +1 @@
+3.10.13

Dockerfile

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+FROM ubuntu:22.04
+RUN useradd -u 1001 testuser
+RUN apt-get update \
+    && apt-get install python3 python3-pip -y \
+    && mkdir /app/ \
+    && mkdir /req/
+ADD requirements.txt /req/
+RUN pip install -r /req/requirements.txt
+ADD app /app
+EXPOSE 5000
+# Use this user here, because of permissions
+USER testuser
+ENTRYPOINT ["python3"]
+CMD ["/app/app.py"]

README.md

@@ -1 +1,30 @@
-# devops-programme
+# devops-programme
+
+## How to build it on Ubuntu 22.04 LTS
+```bash
+$ sudo docker build -t test:v0.1 .
+
+...
+Successfully built 14fd734fcfc3
+Successfully tagged test:v0.1
+
+$ sudo docker images
+REPOSITORY                                  TAG                     IMAGE ID       CREATED         SIZE
+test                                        v0.1                    14fd734fcfc3   5 minutes ago   476MB
+```
+
+## How to run it on Ubuntu 22.04 LTS
+```bash
+$ sudo docker build -t test:v0.1 .
+2ff974622935c628227b58162eba6445d22cbba9272bd35a4f2dbe4992dd7a6e
+
+$ sudo docker ps -a
+CONTAINER ID   IMAGE            COMMAND                  CREATED         STATUS                       PORTS                                       NAMES
+2ff974622935   test:v0.1        "python3 /app/app.py"    4 minutes ago   Up 4 minutes                 0.0.0.0:5000->5000/tcp, :::5000->5000/tcp   nifty_bose
+
+$ netstat -nltp | grep 5000
+tcp        0      0 0.0.0.0:5000            0.0.0.0:*               LISTEN      -
+
+$ curl http://127.0.0.1:5000/
+Hello, World!
+```

app/app.py

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+import os
+
+from flask import Flask
+
+app = Flask(__name__)
+
+
+@app.route("/")
+def hello_world():
+    return "Hello, World!"
+
+
+if __name__ == "__main__":
+    # Allow running on localhost
+    app.run(debug=True, host='0.0.0.0', port=os.environ.get("PORT", 5000))

app/app_test.py

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+import unittest
+
+from app import app
+
+
+class TestApp(unittest.TestCase):
+    def setUp(self):
+        self.client = app.test_client()
+
+    def test_hello_world(self):
+        response = self.client.get("/")
+        self.assertEqual(response.status_code, 200)
+        self.assertEqual(response.data, b"Hello, World!")
+
+
+if __name__ == "__main__":
+    unittest.main()

requirements.txt

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+blinker==1.6.3 ; python_version >= "3.10" and python_version < "4.0"
+click==8.1.7 ; python_version >= "3.10" and python_version < "4.0"
+colorama==0.4.6 ; python_version >= "3.10" and python_version < "4.0" and platform_system == "Windows"
+flask==3.0.0 ; python_version >= "3.10" and python_version < "4.0"
+itsdangerous==2.1.2 ; python_version >= "3.10" and python_version < "4.0"
+jinja2==3.1.2 ; python_version >= "3.10" and python_version < "4.0"
+markupsafe==2.1.3 ; python_version >= "3.10" and python_version < "4.0"
+werkzeug==3.0.0 ; python_version >= "3.10" and python_version < "4.0"