Create Installer of Python Program for Windows OS using Inno Setup

Introduction

This article is continuation of article Bundle Large Python Application using PyInstaller. Before moving to next section, it is recommended to read the previous article.

Inno Setup is a free installer for Windows programs. Some of it's key features are

Supports creation of a single EXE to install your program for easy online distribution.
Extensive support for both administrative and non-administrative installations.
Customizable setup types, e.g. Full, Minimal, Custom.
Complete uninstall capabilities.
Running other programs before, during or after install.
Support for password-protected and encrypted installs.

Prerequisite

Download and Install Inno Setup (Preview)

Script Format

Inno Setup scripts are arranged into sections. Each section controls a different aspect of the installation. A section is started by specifying the name of the section enclosed in square brackets []. Inside each section is any number of entries.

You can put comments in the script by placing semicolon at the beginning of the line.
It is legal to specify multiple sections of the same name.

Directory Constants

I have included some of the commonly used constants below

{app}: The application directory, which the user selects on the Select Destination Location page of the wizard.
{src}: The directory in which the Setup files are located.
{pf}: The path of the system's Program Files directory.
{username}: The name of the user who is running Setup or Uninstall program.
{sd}: System Drive. The drive Windows is installed on, typically "C:".
{commondesktop}: The path to desktop folder.
{group}: The path to the Start Menu folder, as selected by the user on Setup's Select Start Menu Folder wizard page. This folder is created under the All Users profile unless the user installing the application does not have administrative privileges, in which case it is created in the user's profile.

Setup section

This section contains global settings used by the installer and uninstaller. Certain directives are required for any installation you create. Here is an example of a Setup section:

[Setup]
AppName=My Program
AppVersion=1.5
DefaultDirName={pf}\My Program
DefaultGroupName=My Program

AppName: This required directive specifies the name of the application being installed.
AppVersion: This directive specifies the version number of the application being installed.
DefaultDirName: The value of this required directive is used for the default directory name, which is used in the Select Destination Location page of the wizard.
DefaultGroupName: The value of this directive is used for the default Start Menu folder name on the Select Start Menu Folder page of the wizard.
You can read official documentation of setup section to know more.

Files section

This optional section defines any files Setup is to install on the user's system. Here is an example of a Files section:

[Files]
Source: "CTL3DV2.DLL"; DestDir: "{sys}"; Flags: onlyifdoesntexist uninsneveruninstall
Source: "MYPROG.EXE"; DestDir: "{app}"
Source: "MYPROG.CHM"; DestDir: "{app}"
Source: "README.TXT"; DestDir: "{app}"; Flags: isreadme

Source: The name of the source file. This can be a wildcard to specify a group of files in a single entry. When a wildcard is used, all files matching it use the same options.
DestDir: The directory where the file is to be installed on the user's system. Will almost always begin with one of the directory constants.
Please follow official documentation of Files section to know more.

Run section

Run section is optional, and specifies any number of programs to execute after the program has been successfully installed, but before the Setup program displays the final dialog. Programs are executed in the order they appear in the script. By default, when processing a Run entry, Setup will wait until the program has terminated before proceeding to the next.

[Run]
Filename: "{app}\INIT.EXE"; Parameters: "/x"
Filename: "{app}\README.TXT"; Description: "View the README file"; Flags: postinstall shellexec skipifsilent
Filename: "{app}\MYPROG.EXE"; Description: "Launch application"; Flags: postinstall nowait skipifsilent unchecked

You can read official documentation to know about more.

Other important sections

Inno Setup supports collection of different sections. As I have covered, few commonly used sections but depending upon the requirements, you can use other sections. I recommend to have a look on Dirs, Icons, Tasks, Registry and Code sections.