addie

Initial Docker Image Build

As conventionally, the ADDIE (ADvanced DIffraction Environment, available at addie.ornl.gov) service is deployed on a VPS (specifically, an instance on the ORNL hosted research cloud). The service itself and all the necessary configurations are therefore locked to the VPS machine, making it extremely painful for transfer and maintenance. Especially for the maintenance, anytime we need to install a new functionality into the ADDIE service, unavoidably we would need some new dependencies. However, the existing modules and libraries will potentially be conflicting with the module we are trying to install and quite often we need to do the homework for testing and find out the compatible versions of all the modules (existing ones and those to be installed). Doing such on a VPS locally is rather risky as once the installed new module breaks some other modules, it is very difficult, or sometimes even impossible, to roll back. So, from the long run, we need to make the service containerized, using, e.g., docker so the whole service is self-contained and more importantly, the testing will become way easier. We just need to pull the docker image, fire up a container and perform the installation and test interactively. Once finished, we can then push the image to a new version and deploy it on the VPS via docker. This blog will keep a record of the preparation of the docker image for ADDIE. The procedure may not be the optimal one, as the finally prepared docker image is with the size of ~10 Gb. But at least, it will give us a working version of the docker image, with which we can then easily fire up a ADDIE service instance on any supported VPS.

N.B. The reason why the docker image is large is that we include all the required modules and configurations in the image. We could probably do the installation and configuration via docker entrypoint or startup script. But in this case, I will not go through that route, and in my case, the image is huge, but the startup script is very simple.

Pull a startup docker image, e.g.,
```
 docker pull ubuntu
```
Run the pulled docker image interactively,
```
 docker run -i -t ubuntu bash
```

where the ubuntu refers to the pulled docker image name.

Within the interactive docker container, install all the necessary packages,

 apt install git
 apt install gfortran
 apt install build-essential
 apt install vim
 apt install wget
 apt install curl
 wget https://repo.anaconda.com/miniconda/Miniconda3-latest-Linux-x86_64.sh -P /tmp & bash /tmp/Miniconda3-latest-Linux-x86_64.sh
 apt install python-wxtools
 curl https://subversion.xray.aps.anl.gov/admin_pyGSAS/downloads/gsas2full-Latest-Linux-x86_64.sh > /tmp/gsas2full-Latest-Linux-x86_64.sh
 bash /tmp/gsas2full-Latest-Linux-x86_64.sh -b -p ~/g2full
 apt install redis-server

curl and python-wxtools are needed for running GSASII. Without python-wxtools, running GSASII will complain about wx not found.

GSASII also needs libgfortran.so.4 to run and usually the library file is not available in the startup image. We can download this file here and put it somewhere in the docker container (e.g., /usr/lib64) which we will use later on.

Clone the source code of ADDIE (assuming we are located at / in the docker container on the command line),
```
 git clone https://code.ornl.gov/general/tsitc.git
```
We need the token for login. Go to Settings -> Access Tokens -> Add new token, and select proper permission, select the expiration date and then copy the generated token.
Create a conda environment,
```
 conda create -n py37 python=3.7
 conda activate py37
```
The Diffpy-CMI module is only compatible with Python=3.7, so we have to stay with it for the moment, even the Python=3.7 has been dropped for support.
Go into the tsitc directory and install all the required python modules,
```
 pip install -r requirements.txt
```

Install Diffpy-CMI,

 conda config --add channels diffpy
 conda install diffpy-cmi

Install strumining,
```
 git clone https://code.ornl.gov/ly0/strumining.git
 cd strumining
 pip install pymatgen
 pip install pybtex
 pip install PyYAML
 python setup.py install
```
After the installation, we need to manually copy over two folders (data and utils) in the strumining source code tree to the corresponding location in the conda environment. In my case, the destination is,
```
 /root/miniconda3/envs/py37/lib/python3.7/site-packages/strumining-1.0.0-py3.7.egg/strumining
```
The specific location will depend on the conda installation location and the conda environment we created previously.
Finally, we need to copy over the instance folder (download the zip file here, get in touch with Yuanpeng for access passcode) to the /tsitc directory.

With the recent update to include the LDAP authentication, there is another file ldap_blueprint.py under the pdfitc directory that needs to be copied over manually, as this file contains sensitive authentication information which should not be included in the git history.

Also with the LDAP implementation, we need to install the flask-session, flask-wtf, pyldap, and pyoncat modules,
```
 conda install conda-forge::flask-session
 conda install anaconda::flask-wtf
 pip install pyldap
 pip install https://oncat.ornl.gov/packages/pyoncat-1.5.1-py3-none-any.whl
```
When installing pyldap with pip, we might come across with errors relevant to the gcc failure, in which case the following command might be helpful [12],
```
 sudo apt install libsasl2-dev libldap2-dev libssl-dev
```
Going through all the procedures as detailed above, the container should be ready to be committed to a new image with which we can then fire up an ADDIE service.
Exit the docker container – just execute exit from the command line.

After exiting the container, if we want to run the container again in the interactive mode, use the following command,
```
docker exec -it [CCONTAINER_NAME] bash
```
Commit the container to a new image. First, we can check the running container(s) using the command,
```
docker ps -a
```
Identifying the container we were working on by its name and ID, then,
```
docker commit [CONTAINER_ID] flask_addie
```
Use the command docker images to check the new committed image in the docker image list.

The flask_addie here refers to the name of the image to be created by the commitment. It could be possible that an image with the same name already exists on the local host. In such a situation, the existing image with the same name as, e.g., flask_addie, will be renamed to <none> and the new flask_addie stays the latest.
Prepare a Dockerfile file, as below,
```
FROM flask_addie

WORKDIR /tsitc

COPY startup.sh /

CMD ["/bin/bash", "-c", "/startup.sh"]
```
where flask_addie is just the name of the new committed docker image in previous step. The name can be whatever we prefer to use. To avoid confusion, we can choose a new name anytime we commit the new image from a container – I am not sure whether committing a container to an already existing image will cause any issues.
In the same folder (now, we already existed the docker container and we are on the host machine) as the Dockerfile file, we need to create a startup.sh file as below,
```
#!/bin/bash

source /root/miniconda3/etc/profile.d/conda.sh
conda activate py37
export LD_LIBRARY_PATH='/usr/lib64'
gunicorn -w 3 -b :5000 run:app &
redis-server --port 6379 &
celery -A pdfitc.app.celery worker --loglevel=info
```
N.B. The startup script will be run when launching the docker image and it will be running in the linux environment. So, if we were preparing the startup.sh file on Windows, the file ending will cause some issues, in which case, we may need to edit the file using special solutions, e.g., in WSL linux environment on Windows.

The export command is for exporting the library system path so that the GSASII program can find the libgfortran.so.4 that we previously put in the /usr/lib64 directory.

In the last line of the startup script, we don’t need the & sign so that the process will be running as the for-ground process without releasing the process. If we put an & sign to the end of the command, docker will exit immediately after running the last command since he thinks that he has gone over all the processes and will exit without worrying about those jobs running in the background.
Build the docker image,
```
docker image build -t flask_addie .
```
Again, the flask_addie here refers to the image to be created via the image building. Same as the comments above, if a local image of the same name already exists, the existing image will be renamed to <none>, with the new flask_addie staying the latest.
Fire up the container,
```
docker run -p 5000:5000 -d flask_addie
```
The Flask server should be now accessible from the host machine, at localhost:5000.
Push the local docker image to the Docker Hub,
```
docker login --username=apw247
docker tag bb38976d03cf apw247/flask_addie:latest
docker push apw247/flask_addie
```
where bb38976d03cf is the docker image ID which we can obtain via the command,
```
docker images
```
to see all the existing images on our host machine and we can identify the associated image ID with the flask_addie image.

For security purpose, the remote docker repository is made private. To contribute to the repo, please get in touch with Yuanpeng to request access.

Development

Following the procedures above, we now have the docker image to start with. For further development, we need a) new codes, b) local testing, c) making new docker image, and d) deployment. In this section, we will focus the local testing, assuming that we have put in our new codes. The source codes for ADDIE is hosted on ORNL gitlab server, https://code.ornl.gov/general/tsitc. The master branch corresponds to the current deployed production version. The docker branch is specifically for the the docker version of the service, as the GSASII installation location is different in the docker image and the server where the current service is deployed. The docker_dev branch is for the development and testing of the docker version. Here follows are given the detailed steps to do the local testing,

Commit and push the new codes to be tested to the docker_dev branch.

The source code is also protected, so, to contribute, get in touch with Yuanpeng .

Pull the docker image, check local images and run the image as a container interactively,

 docker pull apw247/flask_addie:latest
 docker images
 docker run -i -t apw247/flask_addie bash

Within the docker container, change directory to the source code repo of ADDIE, pull the codes and exit the container,
```
 cd /tsitc
 git checkout docker_dev
 git pull
 exit
```
There should be a better way to build the docker image to include such steps in the startup running script. But I will stay with the slightly tedious steps here, which is actually not too tedious.

To prevent the popup request for username and the token any time when running the git push or pull command, we could run the following command (before running git push or git pull) to remember the passcode for git,
```
 git config --global credential.helper store
```
Check the running container, identify the one we were just working with, and commit the container to a new image,
```
 docker commit [CONTAINER_ID] flask_addie
```
On the local machine, change directory to the tsitc repo and further into the docker directory inside the repo – clone the source repo if not yet cloned.
Follow the steps 13-15 in previous section to build the new image and run the service locally for testing.

Deployment

For deployment, the initial steps are quite similar to the development procedures as detailed in the Development section above. The only difference is that we need to check out the master branch instead of the docker_dev one. After all the initial steps, we need to push the new docker image to Docker Hub, following the instruction as presented in step-18 in the first section.
Finally, on the remote VPS, we need to run,
```
 docker run -p 5000:5000 -d flask_addie
```
to start up the server and then we can configure nginx to redirect the traffic on the port 443 to the local 5000 port.