snmp-fetch 0.1.6

An opinionated python SNMPv2 library built for rapid database ingestion.

An opinionated python3.7 SNMPv2 library designed for rapid database ingestion.

Prerequisites

Snmp-fetch is built for python 3.7 and c++17. Building is currently only tested on gcc 8 and each release is only tested against the latest version of each prerequisite dependency. The following prerequisites must be installed before adding snmp-fetch to your project.

net-snmp

A recent version of net-snmp is required; testing has only been performed against net-snmp 5.8.

# perl bindings may be needed on RPM based systems
sudo yum install perl-devel

# compile and install net-snmp
wget https://sourceforge.net/projects/net-snmp/files/net-snmp/5.8/net-snmp-5.8.tar.gz/download -O net-snmp.tar.gz
tar xzfv net-snmp.tar.gz
cd net-snmp-5.8
./configure --enable-ipv6 --with-defaults
make
sudo make install
cd .. && rm -rf net-snmp*
sudo ldconfig -v

boost (headers only)

Boost is a popular C++ library to reduce boilerplate. Snmp-fetch makes use of some of the header only libraries.

wget https://dl.bintray.com/boostorg/release/1.71.0/source/boost_1_71_0.tar.gz
tar xzfv boost_1_71_0.tar.gz
sudo mv boost_1_71_0/boost /usr/local/include/
rm -rf boost_1_71_0*

pybind11

Pybind11 is a C++ wrapper around the Python C API to reduce boilerplate. This is a header only library, but the test script will attempt to build a binary.

# install pytest in the user space for the test build
pip3.7 install --user pytest

# install cmake
wget https://github.com/Kitware/CMake/releases/download/v3.15.4/cmake-3.15.4-Linux-x86_64.sh
chmod a+x cmake-3.15.4-Linux-x86_64.sh
sudo ./cmake-3.15.4-Linux-x86_64.sh \
  --prefix=/usr/local/ \
  --exclude-subdir \
  --skip-license
rm cmake-3.15.4-Linux-x86_64.sh

# test and install pybind11
wget https://github.com/pybind/pybind11/archive/v2.4.3.tar.gz -O pybind11.tar.gz
tar -xvf pybind11.tar.gz
cd pybind11-2.4.3
mkdir -p build && cd build
cmake .. -DPYBIND11_CPP_STANDARD=-std=c++17 -DDOWNLOAD_CATCH=1
make check -j 4
sudo make install
cd ../../
rm -rf pybind11*

Installation

# poetry
poetry add snmp-fetch --no-dev
# pip
pip install snmp-fetch

Development

Poetry is required for the development of snmp-fetch.

# add the testing framework
wget -P tests/capi https://raw.githubusercontent.com/catchorg/Catch2/master/single_include/catch2/catch.hpp

# clone the repository
git clone https://github.com/higherorderfunctor/snmp-fetch.git
cd snmp-fetch

# setup the virtual environment - mypy uses symbolic links in the 'stubs' directory to
# expose packages that play nicely with the static type checker
virtualenv -p python3.7 ENV
source ENV/bin/activate
poetry install

# python linting
poetry run isort -rc --atomic .
poetry run pylint snmp_fetch tests
poetry run flake8 snmp_fetch tests
poetry run mypy -p snmp_fetch -p tests
poetry run bandit -r snmp_fetch

# C++ linting
# TODO

# python testing
poetry run pytest -v --hypothesis-show-statistics tests
# fail fast testing
poetry run pytest -x --ff tests

# C++ testing (GCC)
g++ -std=c++17 `python-config --cflags` -O0 \
  src/capi/*.cpp \
  tests/capi/test_capi.cpp \
  -o test_capi \
  -L"$(python-config --prefix)/lib" \
  `python-config --ldflags` \
  `net-snmp-config --libs`
LD_LIBRARY_PATH="$(python-config --prefix)/lib" ./test_capi

# C++ testing (CLANG)
# TODO

Known Limitations

• The library only supports SNMPv2 at this time.

• BULKGET_REQUEST and NEXT_REQUEST will always perform a walk.

• Walks will always end if the root of the OID runs past the requested OID.

• Duplicate objects on the same host/request will be silently discarded.

  • This includes the initial request; walks must be performed on an OID prior to the first desired.

• NO_SUCH_INSTANCE, NO_SUCH_OBJECT, and END_OF_MIB_VIEW response variable bindings are exposed as errors for handling by the client.