In the quest^Wrather leisurely ambulation towards the smallest possible Docker image for Pharo for running headless, batch and server-side applications, one approach is to reduce the size of the Pharo VM, by removing irrelevant built-in and external plugins, also known as modules.

Here's what a pharo.cog.spur.minheadless VM built yesterday produces from STON toStringPretty: Smalltalk vm listBuiltinModules:

'[
	''SqueakFFIPrims'',
	''IA32ABI VMMaker.oscog-eem.2480 (i)'',
	''FilePlugin VMMaker.oscog-eem.2530 (i)'',
	''FileAttributesPlugin FileAttributesPlugin.oscog-eem.50 (i)'',
	''LargeIntegers v2.0 VMMaker.oscog-eem.2530 (i)'',
	''LocalePlugin VMMaker.oscog-eem.2495 (i)'',
	''MiscPrimitivePlugin VMMaker.oscog-eem.2480 (i)'',
	''SecurityPlugin VMMaker.oscog-eem.2480 (i)'',
	''SocketPlugin VMMaker.oscog-eem.2568 (i)'',
	''B2DPlugin VMMaker.oscog-eem.2536 (i)'',
	''BitBltPlugin VMMaker.oscog-nice.2587 (i)'',
	''FloatArrayPlugin VMMaker.oscog-eem.2480 (i)'',
	''FloatMathPlugin VMMaker.oscog-eem.2480 (i)'',
	''Matrix2x3Plugin VMMaker.oscog-eem.2480 (i)'',
	''DropPlugin VMMaker.oscog-eem.2480 (i)'',
	''ZipPlugin VMMaker.oscog-eem.2480 (i)'',
	''ADPCMCodecPlugin VMMaker.oscog-eem.2480 (i)'',
	''AsynchFilePlugin VMMaker.oscog-eem.2493 (i)'',
	''BMPReadWriterPlugin VMMaker.oscog-eem.2480 (i)'',
	''DSAPrims CryptographyPlugins-eem.14 (i)'',
	''FFTPlugin VMMaker.oscog-eem.2480 (i)'',
	''FileCopyPlugin VMMaker.oscog-eem.2493 (i)'',
	''JoystickTabletPlugin VMMaker.oscog-eem.2493 (i)'',
	''MIDIPlugin VMMaker.oscog-eem.2493 (i)'',
	''SerialPlugin VMMaker.oscog-eem.2493 (i)'',
	''SoundCodecPrims VMMaker.oscog-eem.2480 (i)'',
	''SoundGenerationPlugin VMMaker.oscog-eem.2480 (i)'',
	''StarSqueakPlugin VMMaker.oscog-eem.2480 (i)'',
	''Mpeg3Plugin VMMaker.oscog-eem.2495 (i)'',
	''VMProfileLinuxSupportPlugin VMMaker.oscog-eem.2480 (i)'',
	''UnixOSProcessPlugin VMConstruction-Plugins-OSProcessPlugin.oscog-dtl.66 (i)''
]'

And here's the directory listing of the VM as built:

~/src/opensmalltalk-vm/products/ph64mincogspurlinuxht% ls
libAioPlugin.so*             libPharoVMCore.a             libSqueakSSL.so*             libssh2.so@
libCroquetPlugin.so*         libRePlugin.so*              libSurfacePlugin.so*         libssh2.so.1@
libEventsHandlerPlugin.so*   libSDL2-2.0.so.0@            libcrypto.so.1.1*            libssh2.so.1.0.1*
libInternetConfigPlugin.so*  libSDL2-2.0.so.0.7.0*        libgit2.so@                  libssl.so@
libJPEGReadWriter2Plugin.so* libSDL2.so@                  libgit2.so.0.26.8*           libssl.so.1.1*
libJPEGReaderPlugin.so*      libSDL2DisplayPlugin.so*     libgit2.so.26@               pharo*

For server-side applications, a number of the plugins and shared libraries (certainly also libPharoVMCore.a) need not be part of the Docker image.

Tags: Alpine Linux, deployment, Docker