TensorRT installation warning for onnx_to_trt (nv-morpheus#23)

* tensorrt installation warning for onnx_to_trt

* Update cli.py

* .

* .

* add better error message for tensorrt requirement, add tensorrt to sphinx mocks

docs/source/conf.py

@@ -89,6 +89,7 @@
 autodoc_mock_imports = [
     "morpheus.cli",  # Dont document the CLI in Sphinx
     "tqdm",
+    "tensorrt",
 ]
 
 # Config numpydoc

morpheus/utils/onnx_to_trt.py

@@ -12,8 +12,21 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import logging
+
 from morpheus.config import ConfigOnnxToTRT
 
+logger = logging.getLogger(__name__)
+
+try:
+    import tensorrt as trt
+except ImportError:
+    logger.error("The onnx_to_trt module requires the TensorRT runtime and python package to be installed. "
+                 "To install the `tensorrt` python package, follow the instructions located "
+                 "here: https://docs.nvidia.com/deeplearning/tensorrt/install-guide/index.html#installing-pip")
+    raise
+
+
 
 def gen_engine(c: ConfigOnnxToTRT):
     """
@@ -27,7 +40,7 @@ def gen_engine(c: ConfigOnnxToTRT):
     """
 
     # Local imports to avoid requiring TensorRT to generate the docs
-    import tensorrt as trt
+
     TRT_LOGGER = trt.Logger()
 
     input_model = c.input_model