First search in installed packages

Author: tmi

.gitignore

@@ -22,4 +22,6 @@ __pycache__/
 .vscode/*.code-snippets
 
 # Ignore code-workspaces
-*.code-workspace
+*.code-workspace
+
+*swp

findlibs/__init__.py

@@ -10,6 +10,7 @@
 
 import configparser
 import ctypes.util
+import importlib
 import os
 import sys
 from pathlib import Path
@@ -21,6 +22,48 @@
     "win32": ".dll",
 }
 
+def _find_in_package(lib_name: str, pkg_name: str) -> str|None:
+    """Tries to find the library in an installed python module `{pgk_name}libs`.
+    This assumes convention used by newly built binary-only ecmwf packages, eg, eckit shared libs
+    ending up in "eckitlib" python module."""
+    # NOTE we could have searched for relative location wrt __file__ -- but that breaks eg
+    # editable installs of findlibs, conda-venv combinations, etc. The price we pay is that
+    # the binary packages have to be importible, ie, the default output of auditwheel wont work
+    try:
+        module = importlib.import_module(pkg_name + "libs")
+        venv_wheel_lib = str((Path(module.__file__) / '..' / lib_name).resolve())
+        if os.path.exists(venv_wheel_lib):
+            return venv_wheel_lib
+    except ImportError:
+        pass
+    return None
+
+def _find_in_python(lib_name: str, pkg_name: str) -> str|None:
+    """Tries to find the library installed directly to Conda/Python sys.prefix libs"""
+    roots = [sys.prefix]
+    if "CONDA_PREFIX" in os.environ:
+        roots.append(os.environ["CONDA_PREFIX"])
+
+    for root in roots:
+        for lib in ("lib", "lib64"):
+            fullname = os.path.join(root, lib, lib_name)
+            if os.path.exists(fullname):
+                return fullname
+    return None
+
+def _find_in_home(lib_name: str, pkg_name: str) -> str|None:
+    env_prefixes = [pkg_name.upper(), pkg_name.lower()]
+    env_suffixes = ["HOME", "DIR"]
+    envs = ["{}_{}".format(x, y) for x in env_prefixes for y in env_suffixes]
+
+    for env in envs:
+        if env in os.environ:
+            home = os.path.expanduser(os.environ[env])
+            for lib in ("lib", "lib64"):
+                fullname = os.path.join(home, lib, lib_name)
+                if os.path.exists(fullname):
+                    return fullname
+    return None
 
 def _get_paths_from_config():
     locations = [
@@ -71,72 +114,27 @@ def _get_paths_from_config():
 
     return paths
 
-
-def find(lib_name, pkg_name=None):
-    """Returns the path to the selected library, or None if not found.
-
-    Arguments
-    ---------
-    lib_name : str
-        Library name without the `lib` prefix. The name of the library to
-        find is formed using ``lib_name`` and a platform specific suffix
-        (by default ".so"). E.g. when ``lib_name`` is "eccodes" the library
-        name will be "libeccodes.so" on Linux and "libeccodes.dylib"
-        on macOS.
-    pkg_name :  str, optional
-        Package name if it differs from the library name. Defaults to None.
-
-    Returns
-    --------
-    str or None
-        Path to selected library
-    """
-    pkg_name = pkg_name or lib_name
-    extension = EXTENSIONS.get(sys.platform, ".so")
-    libname = "lib{}{}".format(lib_name, extension)
-
-    # sys.prefix/lib, $CONDA_PREFIX/lib has highest priority;
-    # otherwise, system library may mess up anaconda's virtual environment.
-
-    roots = [sys.prefix]
-    if "CONDA_PREFIX" in os.environ:
-        roots.append(os.environ["CONDA_PREFIX"])
-
-    for root in roots:
-        for lib in ("lib", "lib64"):
-            fullname = os.path.join(root, lib, libname)
-            if os.path.exists(fullname):
-                return fullname
-
-    env_prefixes = [pkg_name.upper(), pkg_name.lower()]
-    env_suffixes = ["HOME", "DIR"]
-    envs = ["{}_{}".format(x, y) for x in env_prefixes for y in env_suffixes]
-
-    for env in envs:
-        if env in os.environ:
-            home = os.path.expanduser(os.environ[env])
-            for lib in ("lib", "lib64"):
-                fullname = os.path.join(home, lib, libname)
-                if os.path.exists(fullname):
-                    return fullname
-
-    config_paths = _get_paths_from_config()
-
-    for root in config_paths:
+def _find_in_config_paths(lib_name: str, pkg_name: str) -> str|None:
+    paths = _get_paths_from_config()
+    for root in paths:
         for lib in ("lib", "lib64"):
-            filepath = root / lib / f"lib{lib_name}{extension}"
+            filepath = root / lib / lib_name
             if filepath.exists():
                 return str(filepath)
+    return None
 
+def _find_in_ld_path(lib_name: str, pkg_name: str) -> str|None:
     for path in (
         "LD_LIBRARY_PATH",
         "DYLD_LIBRARY_PATH",
     ):
         for home in os.environ.get(path, "").split(":"):
-            fullname = os.path.join(home, libname)
+            fullname = os.path.join(home, lib_name)
             if os.path.exists(fullname):
                 return fullname
+    return None
 
+def _find_in_sys(lib_name: str, pkg_name: str) -> str|None:
     for root in (
         "/",
         "/usr/",
@@ -146,8 +144,48 @@ def find(lib_name, pkg_name=None):
         os.path.expanduser("~/.local"),
     ):
         for lib in ("lib", "lib64"):
-            fullname = os.path.join(root, lib, libname)
+            fullname = os.path.join(root, lib, lib_name)
             if os.path.exists(fullname):
                 return fullname
+    return None
 
+def _find_in_ctypes_util(lib_name: str, pkg_name: str) -> str|None:
     return ctypes.util.find_library(lib_name)
+
+def find(lib_name: str, pkg_name: str|None = None) -> str|None:
+    """Returns the path to the selected library, or None if not found.
+
+    Arguments
+    ---------
+    lib_name : str
+        Library name without the `lib` prefix. The name of the library to
+        find is formed using ``lib_name`` and a platform specific suffix
+        (by default ".so"). E.g. when ``lib_name`` is "eccodes" the library
+        name will be "libeccodes.so" on Linux and "libeccodes.dylib"
+        on macOS.
+    pkg_name :  str, optional
+        Package name if it differs from the library name. Defaults to None.
+
+    Returns
+    --------
+    str or None
+        Path to selected library
+    """
+    pkg_name = pkg_name or lib_name
+    extension = EXTENSIONS.get(sys.platform, ".so")
+    lib_name = "lib{}{}".format(lib_name, extension)
+
+    sources = [
+        _find_in_package,
+        _find_in_python,
+        _find_in_home,
+        _find_in_config_paths,
+        _find_in_ld_path,
+        _find_in_sys,
+        _find_in_ctypes_util,
+    ]
+
+    for source in sources:
+        if (result := source(lib_name, pkg_name)):
+            return result
+    return None