Currently breaking CIs: AMQP/Kombu dependency conflict

[GuiTeK]

SUMMARY

The ST2 requirements.txt currently on master (from commit a9f72ae) requires amqp==2.5.0 and kombu==4.6.4. The problem is, kombu==4.6.4 requires amqp==2.5.1, so there is a dependency conflict.

Pip fails with the following error:

ERROR: kombu 4.6.4 has requirement amqp<3.0,>=2.5.1, but you'll have amqp 2.5.0 which is incompatible.

When using a recent version of pip (e.g. 19.2.2), this will cause pip to fail to install the requirements. However, if you try with an old version (e.g. 8.1.1), it will work. I don't know at which specific version of Pip it stops working.

I think ST2 requirements.txt should require amqp==2.5.1 instead of amqp==2.5.0. I made the PR: #4771

Note: this might be considered urgent because as https://github.com/StackStorm-Exchange/ci uses the master branch of ST2 and not a specific version, it is currently breaking CIs (depending on what version of Pip is used by the CI).

STACKSTORM VERSION

Current master branch, 26ffc2f

OS, environment, install method

N/A

Steps to reproduce the problem

It's easier to reproduce with Docker.

1. Start a container with the following command: docker run -it ubuntu:16.04 /bin/bash
2. Run the following commands inside the Docker container:

apt-get update
apt-get install python3 python3-pip python3-dev git build-essential libffi-dev libssl-dev nano
pip3 install virtualenv # To have a newer version of pip easily
virtualenv st2-amqp-test
cd st2-amqp-test
source ./bin/activate
# Create the st2/requirements.txt file
pip install -r requirements.txt # This will fail

Expected Results

Should correctly install all the dependencies when doing pip install -r requirements.txt.

Actual Results

Pip fails with the following error:

ERROR: kombu 4.6.4 has requirement amqp<3.0,>=2.5.1, but you'll have amqp 2.5.0 which is incompatible.

[blag]

Yep, I've got a PR incoming that fixes this. Thanks!