Installation and customization

PyPI (recommended)

APSW is on PyPI at https://pypi.org/project/apsw/

It can be installed in the same way as other packages:

pip install apsw

When you install from PyPI:

The corresponding SQLite version is embedded privately inside and not affected by or visible to the rest of the machine or even the rest of the process.

This means other modules and libraries will continue using whatever SQLite they would have before. For example Core Data on MacOS uses SQLite, but will not know of or be affected by the SQLite inside APSW.
All extensions are enabled
SQLITE_ENABLE_COLUMN_METADATA is enabled, providing Cursor.description_full

The PyPI releases include pre-built binaries for common platforms. If yours is not covered, then pip will download the source release and automatically compile with the same settings. It will require a C compiler and the Python development header files.

Linux/BSD provided

Most Linux & BSD distributions have packaged APSW which may trail the SQLite and APSW releases by a year, or more. The distribution provided APSW uses the system wide SQLite library.

Debian	Install python3-apsw
Fedora	Install python3-apsw
Ubuntu	Install python3-apsw
Gentoo	Install dev-python/apsw
Arch	Install python-apsw

There is a full list (150+) of distributions, the package name for APSW, and what APSW version they are currently on.

Building and customization

There are currently several different ways (that all work) from the Python packaging solutions.

Build process

No matter what tool is used, ultimately it invokes setup.py. This is a standard way of building C extensions originally provided by distutils, and now by setuptools.

A series of commands and options are given to setup.py in this pattern:

python setup.py cmdone --option --option value cmdtwo --option \
   cmdthree --option --option value

The only necessary command is build. You can get help by --help:

python setup.py build --help

Each command takes options which can be specified on the command line, or in a configuration file named setup.cfg or setup.apsw. The leading double dash on options is omitted, and dashes should become underscores.

# This is used with pypi source and binary builds

[build]
# download corresponding sqlite release
fetch = True
# all extensions included
enable_all_extensions = True
# ... except icu (not abi stable)
omit = icu
# for Cursor.description_full
enable = COLUMN_METADATA

SQLite options

It is important to understand SQLite's compile time options. They provide control over functionality and APIs included or excluded from SQLite.

APSW needs to know the options chosen so it can adapt. For example if extension loading is omitted from SQLite then APSW also needs to omit the same functionality, otherwise compilation or linking will fail.

Finding SQLite

APSW can fetch SQLite as detailed below, and places it in a sqlite3/ subdirectory. You can place your own SQLite in that directory. If there is a sqlite3.c (ie the amalgamation) then it will be statically included inside APSW. A compiled SQLite will be picked up if present. If none of that is present, then the standard compiler locations are used (eg /usr/include on Unix).

If sqlite3/sqlite3config.h is present it is included before sqlite3/sqlite3.c. It is a good location to put platform configuration which APSW's fetch does automatically by running configure.

Source

It is recommended you get the source from Github releases. If you get the source from PyPi then ensure you edit the setup.apsw file inside.

apsw-3.43.1.0.zip (Source, includes this HTML Help)
apsw-3.43.1.0-sigs.zip GPG signatures for all files

Verifying your download

Source releases are digitally signed so you can verify they have not been tampered with. Download and extract the corresponding zip file of signatures. These instructions are for GNU Privacy Guard. (GPG is installed as standard on most Unix/Linux platforms and can be downloaded for Windows.)

Verify

To verify a file use --verify specifying the corresponding .asc filename. This example verifies the source:
$ gpg --verify apsw-3.43.1.0.zip.asc
gpg: Signature made ... date ... using DSA key ID 0DFBD904
gpg: Good signature from "Roger Binns <rogerb@rogerbinns.com>"
If you get a "good signature" then the file has not been tampered with and you are good to go.

Getting the signing key

You may not have the signing key available in which case the last line will be something like this:
gpg: Can't check signature: public key not found
You can get a copy of the key using this command:
$ gpg --keyserver hkp://keyserver.ubuntu.com --recv-keys 0DFBD904
gpg: requesting key 0DFBD904 from hkp server keyserver.ubuntu.com
gpg: /home/username/.gnupg/trustdb.gpg: trustdb created
gpg: key 0DFBD904: public key "Roger Binns <rogerb@rogerbinns.com>" imported
gpg: Total number processed: 1
gpg:               imported: 1
Repeat the verify step.

Commands and their options

These are the relevant setup.py commands and their relevant options.

build

Does the complete build. This will invoke build_ext - use only one of build or build_ext.

--fetch	Fetches the corresponding SQLite version
--enable-all-extensions	Enables all the standard extensions
--enable	A comma separated list of options to enable that are normally off omitting the `SQLITE_ENABLE` prefix. They will be uppercased. eg `--enable column_metadata,fts5`
--omit	A comma separated list of options to omit that are normally enabled omitting the `SQLITE_OMIT` prefix. They will be uppercased. eg `--omit automatic_index`

fetch

This provides more fine grained control over what is fetched.

--version	Specify an explicit version of SQLite to fetch
--fetch-sqlite	Downloads the SQLite amalgamation
--all	Downloads all SQLite components other than the amalgamation. Over time this has included additional extensions and SQLite functions, but currently is nothing.
--missing-checksum-ok	APSW includes checksums of SQLite releases and will fail a fetch if you specify a version for which no checksum is known. This allows proceeding.

build_ext

This performs the compilation of the C code.

--use-system-sqlite-config	Uses `ctypes` to determine the system wide SQLite library compilation options
--definevalues	Additional #defines separated by commas. eg `--definevalues SQLITE_MAX_ATTACHED=37,SQLITE_EXTRA_INIT=mycore_init`
--enable-all-extensions	Enables all the standard extensions
--enable	A comma separated list of options to enable that are normally off omitting the `SQLITE_ENABLE` prefix. They will be uppercased. eg `--enable column_metadata,fts5`
--omit	A comma separated list of options to omit that are normally enabled omitting the `SQLITE_OMIT` prefix. They will be uppercased. eg `--omit automatic_index`

Testing

SQLite itself is extensively tested. It has considerably more code dedicated to testing than makes up the actual database functionality.

APSW includes tests which use the standard Python testing modules to verify correct operation. New code is developed alongside the tests. Reported issues also have test cases to ensure the issue doesn't happen or doesn't happen again.:

$ python3 -m apsw.tests
                Python  /usr/bin/python3 sys.version_info(major=3, minor=10, micro=4, releaselevel='final', serial=0)
Testing with APSW file  /space/apsw/apsw/__init__.cpython-310-x86_64-linux-gnu.so
          APSW version  3.39.2.0
    SQLite lib version  3.39.2
SQLite headers version  3039002
    Using amalgamation  True
...............................................................................................
----------------------------------------------------------------------
Ran 95 tests in 25.990s

OK

The tests also ensure that as much APSW code as possible is executed including alternate paths through the code. 95.5% of the APSW code is executed by the tests. If you checkout the APSW source then there is a script tools/coverage.sh that enables extra code that deliberately induces extra conditions such as memory allocation failures, SQLite returning undocumented error codes etc. That brings coverage up to 99.6% of the code.

A memory checker Valgrind is used while running the test suite. The test suite is run multiple times to make any memory leaks or similar issues stand out. A checking version of Python is also used. See tools/valgrind.sh in the source. The same testing is also done with the compiler's sanitizer option.

To ensure compatibility with the various Python versions, a script downloads and compiles all supported Python versions in both debug and release configurations (and 32 and 64 bit) against the APSW and SQLite supported versions running the tests. See tools/megatest.py in the source.

In short both SQLite and APSW have a lot of testing!