How to use override-stage?

I have a part that only provides 2 files after the build process. This files are being built correctly, but I don’t want to use the standard stage process (autoconf plugin). But the following code doesn’t work:

    override-stage: |
      install -D -m0755 ../parts/openssl098/build/libssl.so.0.9.8 "usr/lib/libssl.so.0.9.8"
      install -D -m0755 ../parts/openssl098/build/libcrypto.so.0.9.8 "usr/lib/libcrypto.so.0.9.8"

I can’t see what I’m doing wrong. Those files are not present on the final snap.

I wonder why you don’t want to use it? You may use the organize keyword to re-arrange the location of the files in the part’s installdir, for more info check out:

snapcraft help plugins

Probably due to the fact that snapcraft keep track of all the files each part installs, but not including the ones you’ve installed to the stagedir manually via scriptlet and thus aren’t copied to the primedir during the prime step(and thus not into the final snap).

If you really want to modify the content installed by a part you should use the override-build scriptlet and operate the files installed in the installdir ($SNAPCRAFT_PART_INSTALL, a.k.a. parts/part_name/install) to ensure it will be tracked by snapcraft:

    override-build: |
      snapcraftctl build
      mkdir --parents $SNAPCRAFT_PART_INSTALL/usr/lib
      mv $SNAPCRAFT_PART_INSTALL/lib/libssl.so.0.9.8 $SNAPCRAFT_PART_INSTALL/usr/lib

A good method to debug this is to run each step separately and inspect the resulting directory’s content using the tree command to verify if the result is desirable:

snapcraft build _part_name_
tree parts/_part_name_/install | less
snapcraft stage _part_name_
tree stage | less
snapcraft prime _part_name_
tree prime | less

Like @Lin-Buo-Ren suggested, try using organize first.

    organize:
      openssl098/build: usr/lib

I do something similar with libraries I need inserted in my snap.

Cheers!

Note you might run into this bug: Bug #1775582 “
organize:{ /: another-dir/ } causes the items under host root directory to be copied in another-dir ” : Bugs : Snapcraft

Well, after a big session of hit and miss, I’ve managed to make it work. The final part is:

openssl098:
  plugin: autotools
  source: https://github.com/openssl/openssl.git
  source-type: git
  source-depth: 1
  source-branch: OpenSSL_0_9_8-stable
  override-pull: |
    snapcraftctl pull
    patch -p0 < ../../../snap/openssl098/ca-dir.patch
    patch -p0 < ../../../snap/openssl098/no-rpath.patch
    sed -i '/^push(@INC/s|)|,".")|' crypto/des/asm/des-586.pl
  override-build: |
    ./config --prefix="/usr" --openssldir="/etc/ssl" shared \
      enable-md2 -Wa,--noexecstack
    sed -i '/^CFLAG=/s/$/ $(CFLAGS)/' Makefile
    make

    mkdir -p $SNAPCRAFT_PART_INSTALL/usr/lib
    mv *.so.0.9.8 $SNAPCRAFT_PART_INSTALL/usr/lib
  organize:
    openssl098/install/usr/lib/*.so.0.9.8: usr/lib/

For some crazy reason, the make install part was not working as expected. That’s why I’m being forced to copy manually the final files to the final location.

Thanks for everyone that answered. Probably I’ll have to come back later with other issues =D