Merge pull request #812 from AnswerDotAI/fastprogress-lazy-import

Lazy import `progress_bar`

Author: jph00

fastcore/_modidx.py

@@ -582,6 +582,7 @@
                                    'fastcore.parallel._done_pg': ('parallel.html#_done_pg', 'fastcore/parallel.py'),
                                    'fastcore.parallel._f_pg': ('parallel.html#_f_pg', 'fastcore/parallel.py'),
                                    'fastcore.parallel.bg_task': ('parallel.html#bg_task', 'fastcore/parallel.py'),
+                                   'fastcore.parallel.import_progress_bar': ('parallel.html#import_progress_bar', 'fastcore/parallel.py'),
                                    'fastcore.parallel.parallel': ('parallel.html#parallel', 'fastcore/parallel.py'),
                                    'fastcore.parallel.parallel_async': ('parallel.html#parallel_async', 'fastcore/parallel.py'),
                                    'fastcore.parallel.parallel_gen': ('parallel.html#parallel_gen', 'fastcore/parallel.py'),

fastcore/parallel.py

@@ -3,8 +3,8 @@
 # AUTOGENERATED! DO NOT EDIT! File to edit: ../nbs/03a_parallel.ipynb.
 
 # %% auto #0
-__all__ = ['threaded', 'startthread', 'startproc', 'parallelable', 'ThreadPoolExecutor', 'ProcessPoolExecutor', 'parallel',
-           'parallel_async', 'bg_task', 'run_procs', 'parallel_gen']
+__all__ = ['threaded', 'startthread', 'startproc', 'parallelable', 'ThreadPoolExecutor', 'ProcessPoolExecutor',
+           'import_progress_bar', 'parallel', 'parallel_async', 'bg_task', 'run_procs', 'parallel_gen']
 
 # %% ../nbs/03a_parallel.ipynb #569d18c6
 from .imports import *
@@ -122,13 +122,16 @@ def map(self, f, items, *args, timeout=None, chunksize=1, **kwargs):
         except Exception as e: self.on_exc(e)
 
 # %% ../nbs/03a_parallel.ipynb #f5327cb3
-try: from fastprogress import progress_bar
-except: progress_bar = None
+def import_progress_bar():
+    try: from fastprogress import progress_bar
+    except ImportError: return None
+    return progress_bar
 
 # %% ../nbs/03a_parallel.ipynb #529e1bb1
 def parallel(f, items, *args, n_workers=defaults.cpus, total=None, progress=None, pause=0,
              method=None, threadpool=False, timeout=None, chunksize=1, **kwargs):
     "Applies `func` in parallel to `items`, using `n_workers`"
+    progress_bar = import_progress_bar()
     kwpool = {}
     if threadpool: pool = ThreadPoolExecutor
     else:
@@ -192,6 +195,7 @@ def _done_pg(queue, items): return (queue.get() for _ in items)
 # %% ../nbs/03a_parallel.ipynb #1122caee
 def parallel_gen(cls, items, n_workers=defaults.cpus, progress=True, **kwargs):
     "Instantiate `cls` in `n_workers` procs & call each on a subset of `items` in parallel."
+    progress_bar = import_progress_bar()
     if not parallelable('n_workers', n_workers): n_workers = 0
     if n_workers==0:
         yield from enumerate(list(cls(**kwargs)(items)))

nbs/03a_parallel.ipynb

@@ -477,6 +477,14 @@
     "show_doc(ProcessPoolExecutor, title_level=4)"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "id": "b1d7c809",
+   "metadata": {},
+   "source": [
+    "We define `import_progress_bar` to lazily import, `fastprogress` depends on `fasthtml` and takes about 1 sec to load"
+   ]
+  },
   {
    "cell_type": "code",
    "execution_count": null,
@@ -485,8 +493,10 @@
    "outputs": [],
    "source": [
     "#| export\n",
-    "try: from fastprogress import progress_bar\n",
-    "except: progress_bar = None"
+    "def import_progress_bar():\n",
+    "    try: from fastprogress import progress_bar\n",
+    "    except ImportError: return None\n",
+    "    return progress_bar"
    ]
   },
   {
@@ -500,6 +510,7 @@
     "def parallel(f, items, *args, n_workers=defaults.cpus, total=None, progress=None, pause=0,\n",
     "             method=None, threadpool=False, timeout=None, chunksize=1, **kwargs):\n",
     "    \"Applies `func` in parallel to `items`, using `n_workers`\"\n",
+    "    progress_bar = import_progress_bar()\n",
     "    kwpool = {}\n",
     "    if threadpool: pool = ThreadPoolExecutor\n",
     "    else:\n",
@@ -990,9 +1001,10 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "#| export \n",
+    "#| export\n",
     "def parallel_gen(cls, items, n_workers=defaults.cpus, progress=True, **kwargs):\n",
     "    \"Instantiate `cls` in `n_workers` procs & call each on a subset of `items` in parallel.\"\n",
+    "    progress_bar = import_progress_bar()\n",
     "    if not parallelable('n_workers', n_workers): n_workers = 0\n",
     "    if n_workers==0:\n",
     "        yield from enumerate(list(cls(**kwargs)(items)))\n",