Add back psutil as a dependency

Author: jtpio

CONTRIBUTING.md

@@ -17,7 +17,7 @@ We recommend using [pipenv](https://docs.pipenv.org/) to make development easier
    ```
 
 2. Create an environment that will hold our dependencies.
-   
+
    ```bash
    cd nbresuse
    pipenv --python 3.6
@@ -32,11 +32,9 @@ We recommend using [pipenv](https://docs.pipenv.org/) to make development easier
 4. Do a dev install of nbresuse and its dependencies
 
    ```bash
-   pip install --editable .[resources]
+   pip install --editable .[dev]
    ```
 
-   To test the behavior of NBResuse without `psutil` installed, run `pip install --editable .` instead.
-
 5. Install and enable the nbextension for use with Jupyter Classic Notebook.
 
    ```bash
@@ -73,7 +71,7 @@ the pre-commit hook should take care of how it should look. Here is how to set u
     ```bash
     pre-commit run
     ```
-	
+
 which should run any autoformatting on your code
 and tell you about any errors it couldn't fix automatically.
 You may also install [black integration](https://github.com/ambv/black#editor-integration)

README.md

@@ -22,11 +22,9 @@ main toolbar in the notebook itself, refreshing every 5s.
 You can currently install this package from PyPI.
 
 ```bash
-pip install nbresuse[resources]
+pip install nbresuse
 ```
 
-The above command will install NBResuse along with `psutil` Python package (which is used for getting hardware usage information from the system). If you would like to install NBResuse _without_ `psutil` (in which case NBResuse does essentially nothing), run `pip install nbresuse` instead.
-
 **If your notebook version is < 5.3**, you need to enable the extension manually.
 
 ```

nbresuse/api.py

@@ -1,14 +1,9 @@
 import json
 
+import psutil
 from notebook.base.handlers import IPythonHandler
 from tornado import web
 
-try:
-    # since psutil is an optional dependency
-    import psutil
-except ImportError:
-    psutil = None
-
 try:
     # Traitlets >= 4.3.3
     from traitlets import Callable
@@ -17,36 +12,30 @@
 
 
 class ApiHandler(IPythonHandler):
-
     @web.authenticated
     async def get(self):
         """
         Calculate and return current resource usage metrics
         """
-        config = self.settings['nbresuse_display_config']
+        config = self.settings["nbresuse_display_config"]
 
-        if psutil:
-            cur_process = psutil.Process()
-            all_processes = [cur_process] + cur_process.children(recursive=True)
+        cur_process = psutil.Process()
+        all_processes = [cur_process] + cur_process.children(recursive=True)
 
-            # Get memory information
-            rss = sum([p.memory_info().rss for p in all_processes])
+        # Get memory information
+        rss = sum([p.memory_info().rss for p in all_processes])
 
-            if callable(config.mem_limit):
-                mem_limit = config.mem_limit(rss=rss)
-            else:  # mem_limit is an Int
-                mem_limit = config.mem_limit
+        if callable(config.mem_limit):
+            mem_limit = config.mem_limit(rss=rss)
+        else:  # mem_limit is an Int
+            mem_limit = config.mem_limit
 
-            limits = {'memory': {
-                'rss': mem_limit
-            }}
-            if config.mem_limit:
-                limits['memory']['warn'] = (mem_limit - rss) < (
-                        mem_limit * config.mem_warning_threshold)
+        limits = {"memory": {"rss": mem_limit}}
+        if config.mem_limit:
+            limits["memory"]["warn"] = (mem_limit - rss) < (
+                mem_limit * config.mem_warning_threshold
+            )
 
-            metrics = {
-                'rss': rss,
-                'limits': limits,
-            }
+        metrics = {"rss": rss, "limits": limits}
 
-            self.write(json.dumps(metrics))
+        self.write(json.dumps(metrics))

setup.py

@@ -23,10 +23,9 @@
         "Programming Language :: Python :: 3",
     ],
     packages=setuptools.find_packages(),
-    install_requires=["notebook>=5.6.0", "prometheus_client"],
-    extras_require={
-        "resources": ["psutil>=5.6.0"],
-        "dev": ["autopep8", "black", "pytest", "flake8", "pytest-cov>=2.6.1", "mock"],
+    install_requires=["notebook>=5.6.0", "prometheus_client", "psutil>=5.6.0"],
+    extres_require={
+        "dev": ["autopep8", "black", "pytest", "flake8", "pytest-cov>=2.6.1", "mock"]
     },
     data_files=[
         ("share/jupyter/nbextensions/nbresuse", glob("nbresuse/static/*")),