Unable to use PDF processing functions due to missing library

[megamattc]

Hello,

I am running kraken on ubuntu 24.04 with python 3.10 in a conda environment. I am unable to apply kraken models to a pdf document to produce OCR-ed text, using the command indicated in the documentation:

kraken -I document.pdf -o document.txt -f pdf binarize segment ocr -m ./models/my_model.mlmodel

An error arises indicating the module _libvips cannot be found, or the library libvips.so.42:

╭─────────────────────────────── Traceback (most recent call last) ────────────────────────────────╮
│ /home/ubuntu/anaconda3/envs/con2/lib/python3.10/site-packages/pyvips/__init__.py:19 in <module>  │
│                                                                                                  │
│    16 # try to import our binary interface ... if that works, we are in API mode                 │
│    17 API_mode = False                                                                           │
│    18 try:                                                                                       │
│ ❱  19 │   import _libvips                                                                        │
│    20 │                                                                                          │
│    21 │   logger.debug('Loaded binary module _libvips')                                          │
│    22                                                                                            │
╰──────────────────────────────────────────────────────────────────────────────────────────────────╯
ModuleNotFoundError: No module named '_libvips'

During handling of the above exception, another exception occurred:

╭─────────────────────────────── Traceback (most recent call last) ────────────────────────────────╮
│ /home/ubuntu/anaconda3/envs/con2/bin/kraken:8 in <module>                                        │
│                                                                                                  │
│   5 from kraken.kraken import cli                                                                │
│   6 if __name__ == '__main__':                                                                   │
│   7 │   sys.argv[0] = re.sub(r'(-script\.pyw|\.exe)?$', '', sys.argv[0])                         │
│ ❱ 8 │   sys.exit(cli())                                                                          │
│   9                                                                                              │
│                                                                                                  │
│ /home/ubuntu/anaconda3/envs/con2/lib/python3.10/site-packages/click/core.py:1157 in __call__     │
│                                                                                                  │
│ /home/ubuntu/anaconda3/envs/con2/lib/python3.10/site-packages/click/core.py:1078 in main         │
│                                                                                                  │
│ /home/ubuntu/anaconda3/envs/con2/lib/python3.10/site-packages/click/core.py:1720 in invoke       │
│                                                                                                  │
│ /home/ubuntu/anaconda3/envs/con2/lib/python3.10/site-packages/click/core.py:1657 in              │
│ _process_result                                                                                  │
│                                                                                                  │
│ /home/ubuntu/anaconda3/envs/con2/lib/python3.10/site-packages/click/core.py:783 in invoke        │
│                                                                                                  │
│ /home/ubuntu/anaconda3/envs/con2/lib/python3.10/site-packages/kraken/kraken.py:374 in            │
│ process_pipeline                                                                                 │
│                                                                                                  │
│   371 │                                                                                          │
│   372 │   # parse pdfs                                                                           │
│   373 │   if format_type == 'pdf':                                                               │
│ ❱ 374 │   │   import pyvips                                                                      │
│   375 │   │                                                                                      │
│   376 │   │   if not batch_input:                                                                │
│   377 │   │   │   logger.warning('PDF inputs not added with batch option. Manual output filena   │
│                                                                                                  │
│ /home/ubuntu/anaconda3/envs/con2/lib/python3.10/site-packages/pyvips/__init__.py:61 in <module>  │
│                                                                                                  │
│    58 │   elif _is_mac:                                                                          │
│    59 │   │   vips_lib = ffi.dlopen('libvips.42.dylib')                                          │
│    60 │   else:                                                                                  │
│ ❱  61 │   │   vips_lib = ffi.dlopen('libvips.so.42')                                             │
│    62 │                                                                                          │
│    63 │   logger.debug('Loaded lib %s', vips_lib)                                                │
│    64                                                                                            │
│                                                                                                  │
│ /home/ubuntu/anaconda3/envs/con2/lib/python3.10/site-packages/cffi/api.py:150 in dlopen          │
│                                                                                                  │
│   147 │   │   │   raise TypeError("dlopen(name): name must be a file name, None, "               │
│   148 │   │   │   │   │   │   │   "or an already-opened 'void *' handle")                        │
│   149 │   │   with self._lock:                                                                   │
│ ❱ 150 │   │   │   lib, function_cache = _make_ffi_library(self, name, flags)                     │
│   151 │   │   │   self._function_caches.append(function_cache)                                   │
│   152 │   │   │   self._libraries.append(lib)                                                    │
│   153 │   │   return lib                                                                         │
│                                                                                                  │
│ /home/ubuntu/anaconda3/envs/con2/lib/python3.10/site-packages/cffi/api.py:834 in                 │
│ _make_ffi_library                                                                                │
│                                                                                                  │
│   831                                                                                            │
│   832 def _make_ffi_library(ffi, libname, flags):                                                │
│   833 │   backend = ffi._backend                                                                 │
│ ❱ 834 │   backendlib = _load_backend_lib(backend, libname, flags)                                │
│   835 │   #                                                                                      │
│   836 │   def accessor_function(name):                                                           │
│   837 │   │   key = 'function ' + name                                                           │
│                                                                                                  │
│ /home/ubuntu/anaconda3/envs/con2/lib/python3.10/site-packages/cffi/api.py:829 in                 │
│ _load_backend_lib                                                                                │
│                                                                                                  │
│   826 │   │   │      "to locate a library called %r" % (name,))                                  │
│   827 │   │   if first_error is not None:                                                        │
│   828 │   │   │   msg = "%s.  Additionally, %s" % (first_error, msg)                             │
│ ❱ 829 │   │   raise OSError(msg)                                                                 │
│   830 │   return backend.load_library(path, flags)                                               │
│   831                                                                                            │
│   832 def _make_ffi_library(ffi, libname, flags):                                                │
╰──────────────────────────────────────────────────────────────────────────────────────────────────╯
OSError: cannot load library 'libvips.so.42': libvips.so.42: cannot open shared object file: No such file or directory.  Additionally, ctypes.util.find_library() 
did not manage to locate a library called 'libvips.so.42'

I have tried installing kraken from the github repository and then installing pyvips manually using pip install pyvips as well as install kraken with the pdf functionality using pip install kraken[pdf]. Both give the above error.

[mittagessen]

I believe pip-pyvips doesn't ship with the libvips shared library but just tries to load it from the host system. Can you try installing libvips42t64? That will most likely make it work.