MetaCall Golang Python Http Example

This example shows how to embed Python into Go using MetaCall inside an HTTP server written in Go. In other words, calling Python functions from Go by using GET or POST. The instructions are focused on Linux but it can be ported to other platforms easily.

Dependencies

For building this example you need Python to be installed in the system (3.9 has been tested). For debian based distros:

sudo apt-get install -y --no-install-recommends build-essential cmake ca-certificates git python3 python3-dev python3-pip

Apart from this, you will need Go installed in order to build the main application. I have used Go 1.17.

Build

Build MetaCall first, with Python loader enabled:

git clone --branch v0.5.4 https://github.com/metacall/core
mkdir core/build && cd core/build
cmake \
	-DNODEJS_CMAKE_DEBUG=On \
	-DOPTION_BUILD_LOADERS_PY=On \
	-DOPTION_BUILD_PORTS=On \
	-DOPTION_BUILD_PORTS_PY=On \
	-DOPTION_BUILD_DETOURS=Off \
	-DOPTION_BUILD_SCRIPTS=Off \
	-DOPTION_BUILD_TESTS=Off \
	-DOPTION_BUILD_EXAMPLES=Off \
	..
cmake --build . --target install
ldconfig /usr/local/lib

Now clone the Go/Python example and build it.

git clone https://github.com/metacall/golang-python-http-example.git
cd golang-python-http-example
go build main.go

Run

From repository root directory, run the following commands:

export LOADER_LIBRARY_PATH="/usr/local/lib"
export LOADER_SCRIPT_PATH="`pwd`"
./main

Testing

For testing the endpoint:

curl localhost:8080/deploy_transaction
# or repeated 1000 times:
for run in {1..1000}; do curl localhost:8080/deploy_transaction; done

For closing the server:

curl localhost:8080/close

Docker

Building and running with Docker:

docker build -t metacall/golang-python-http-example .
docker run --rm -p 8080:8080 -it metacall/golang-python-http-example