How to cache a dependency insallation? - github-actions

Question

I am currently trying to implement a workflow which requires protobuf to be installed. However, on Ubuntu I have to compile this myself. The problem is that this takes quite some time to do so I figured caching this step is the thing to do.
However, I am not sure how I can use actions/cache for this, if at all possible.
The following is how I am installing protobuf and my Python dependencies:
name: Service
on:
push:
branches: [develop, master]
jobs:
test:
runs-on: ubuntu-18.04
steps:
- name: Install protobuf-3.6.1
run: |
wget https://github.com/protocolbuffers/protobuf/releases/download/v3.6.1/protobuf-all-3.6.1.tar.gz
tar -xvf protobuf-all-3.6.1.tar.gz
cd protobuf-3.6.1
./configure
make
make check
sudo make install
sudo ldconfig
- uses: actions/checkout#v2
- name: Install Python dependencies
run: |
python -m pip install --upgrade pip setuptools
pip install -r requirements.txt
How can I cache these run steps s.t. they don't have to run each time?

Answer 1

I tested the following:
name: Service
on:
push:
branches: [develop, master]
jobs:
test:
runs-on: ubuntu-18.04
steps:
- uses: actions/checkout#v2
- name: Load from cache
id: protobuf
uses: actions/cache#v1
with:
path: protobuf-3.6.1
key: protobuf3
- name: Compile protobuf-3.6.1
if: steps.protobuf.outputs.cache-hit != 'true'
run: |
wget https://github.com/protocolbuffers/protobuf/releases/download/v3.6.1/protobuf-all-3.6.1.tar.gz
tar -xvf protobuf-all-3.6.1.tar.gz
cd protobuf-3.6.1
./configure
make
make check
- name: Install protobuf
run: |
cd protobuf-3.6.1
sudo make install
sudo ldconfig
- name: Install Python dependencies
run: |
python -m pip install --upgrade pip setuptools
pip install -r requirements.txt
I would also delete all the source files once it's built.