Installation and customization

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

FreeBSD

databases/py-apsw in Ports

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

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.

Verifying your download

Github 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-3.45.1.0.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.

Building and customization

APSW is configured for standard building (PEP 518)

$ python3 -m build

You will need to update the MANIFEST first if you are providing your own SQLite, or if you are providing a setup.apsw with custom configuration. setuptools is used to compile the extension. You can use it directly instead by invoking setup.py.

Build process

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 inside 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.

setup.py 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, and provides more control than build.

--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

--apsw-no-old-names

Excludes old non PEP 8 complaint name aliases from the extension and type stubs.

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.:

                Python  /usr/bin/python3 sys.version_info(major=3, minor=11, micro=6, releaselevel='final', serial=0) 64bit ELF
Testing with APSW file  /space/apsw/apsw/__init__.cpython-311-x86_64-linux-gnu.so
          APSW version  3.44.0.0
    SQLite lib version  3.44.0
SQLite headers version  3044000
    Using amalgamation  True
.............................................................A message due to RecursionError is possible, and what is being tested
object address  : 0x7fea3c94ada0
object refcount : 1
object type     : 0x9de7a0
object type name: TypeError
object repr     :
lost sys.stderr
object address  : 0x7fea3c94ad40
object refcount : 1
object type     : 0x9de7a0
object type name: TypeError
object repr     :
lost sys.stderr
................................................................
----------------------------------------------------------------------
Ran 125 tests in 26.783s

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. In the source, there is a script that enables extra code that deliberately induces extra conditions such as memory allocation failures, SQLite returning error codes, Python APIs erroring etc. That brings coverage up to 99.6% of the code.

A memory checker Valgrind and compiler sanitizer options are also used for further validation.

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.

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