Add PyInstaller example

Author: gjbex

source-code/README.md

@@ -33,3 +33,5 @@ was used to develop it.
 1. `code-organization`: illustration of how to organize code in packages
    and modules.
 1. `error-handling`: simple illustration of error handling.
+1. `pyinstaller`: illustration of how to use `pyinstaller` to create
+   standalone executables.

source-code/pyinstaller/.gitignore

@@ -0,0 +1,11 @@
+# virtual environment to build applications
+build_env/
+
+# build directory
+build/
+
+# distribution directory
+dist/
+
+# Python cache directories
+__pycache__/

source-code/pyinstaller/README.md

@@ -0,0 +1,39 @@
+# PyInstaller
+
+PyInstaller bundles a Python application and all its dependencies into a single
+package. The user can run the packaged app without installing a Python
+interpreter or any modules.  It is very useful to minimize dependencies.
+
+
+## What is it?
+
+1. `src`: directory with a Python scripts that use the pandas library and that
+   requires access to a CSV file.  Note that the Python scripts dynamically
+   load a module `funcs` that is not in the same directory as the script.
+1. `data.csv`: CSV file that is used by the Python script in `src`.
+1. `requirements.txt`: file listing the Python packages that are required by
+   the Python script in `src`.
+
+
+## How to create the applications?
+
+1. Create a virtual environment and install the required packages:
+   ```bash
+   $ python -m venv build_venv
+   $ source build_venv/bin/activate
+   (venv)$ pip install -r requirements.txt
+   ```
+1. Create the application:
+   ```bash
+   (venv)$ pyinstaller \
+             --onefile \
+             --hidden-import funcs \
+             --collect-submodules funcs \
+             src/sum_columns.py
+   (venv)$ pyinstaller \
+             --onefile \
+             --add-data data.csv:data.csv \
+             --hidden-import funcs \
+             --collect-submodules funcs \
+             src/sum_columns.py
+   ```

source-code/pyinstaller/data.csv

@@ -0,0 +1,4 @@
+A,B,C
+1.2,2.3,4.5
+2.1,3.2,5.4
+3.3,5.5,9.9

source-code/pyinstaller/requirements.txt

@@ -0,0 +1,2 @@
+pyinstaller
+pandas

source-code/pyinstaller/src/prod_columns.py

@@ -0,0 +1,26 @@
+#!/usr/bin/env python3
+
+import argparse
+import pathlib
+import sys
+from lib.funcs import prod_columns
+
+def main():
+    parser = argparse.ArgumentParser()
+    parser.add_argument('input_file', nargs='?',
+                        help='Input CSV file')
+    parser.add_argument('--version', action='store_true',
+                        help='Print Python version and exit')
+    args = parser.parse_args()
+    if args.version:
+        print(sys.version)
+        sys.exit(0)
+    if args.input_file is None:
+        data_dir = pathlib.Path(__file__).parent
+        prod_columns(data_dir / 'data.csv')
+    else:
+        prod_columns(args.input_file)
+
+
+if __name__ == '__main__':
+    main()

source-code/pyinstaller/src/sum_columns.py

@@ -0,0 +1,20 @@
+#!/usr/bin/env python3
+
+import argparse
+import sys
+from lib.funcs import sum_columns
+
+def main():
+    parser = argparse.ArgumentParser()
+    parser.add_argument('input_file', help='Input CSV file')
+    parser.add_argument('--version', action='store_true',
+                        help='Print Python version and exit')
+    args = parser.parse_args()
+    if args.version:
+        print(sys.version)
+        sys.exit(0)
+    sum_columns(args.input_file)
+
+
+if __name__ == '__main__':
+    main()