This has been mirrored from the master repository at https://gitlab.cern.ch/cara/cara. This mirror will be updated periodically, but for the absolute latest version of the code you should consult the CERN gitlab instance.
CARA is a risk assessment tool developed to model the concentration of viruses in enclosed spaces, in order to inform space-management decisions.
CARA models the concentration profile of potential virions in enclosed spaces with clear and intuitive graphs. The user can set a number of parameters, including room volume, exposure time, activity type, mask-wearing and ventilation. The report generated indicates how to avoid exceeding critical concentrations and chains of airborne transmission in spaces such as individual offices, meeting rooms and labs.
The risk assessment tool simulates the long-range airborne spread SARS-CoV-2 virus in a finite volume, assuming a homogenous mixture, and estimates the risk of COVID-19 infection therein. The results DO NOT include short-range airborne exposure (where the physical distance is a significant factor) nor the other known modes of SARS-CoV-2 transmission. Hence, the output from this model is only valid when the other recommended public health & safety instructions are observed, such as adequate physical distancing, good hand hygiene and other barrier measures.
The model used is based on scientific publications relating to airborne transmission of infectious diseases, dose-response exposures and aerosol science, as of February 2021. It can be used to compare the effectiveness of different airborne-related risk mitigation measures.
Note that this model applies a deterministic approach, i.e., it is assumed at least one person is infected and shedding viruses into the simulated volume. Nonetheless, it is also important to understand that the absolute risk of infection is uncertain, as it will depend on the probability that someone infected attends the event. The model is most useful for comparing the impact and effectiveness of different mitigation measures such as ventilation, filtration, exposure time, physical activity and the size of the room, only considering long-range airborne transmission of COVID-19 in indoor settings.
This tool is designed to be informative, allowing the user to adapt different settings and model the relative impact on the estimated infection probabilities. The objective is to facilitate targeted decision-making and investment through comparisons, rather than a singular determination of absolute risk. While the SARS-CoV-2 virus is in circulation among the population, the notion of 'zero risk' or 'completely safe scenario' does not exist. Each event modelled is unique, and the results generated therein are only as accurate as the inputs and assumptions.
CARA was developed by following members of CERN - European Council for Nuclear Research (visit https://home.cern/):
Andre Henriques1, Luis Aleixo1, Marco Andreini1, Gabriella Azzopardi2, James Devine3, Philip Elson4, Nicolas Mounet2, Markus Kongstein Rognlien2,6, Nicola Tarocco5
1HSE Unit, Occupational Health & Safety Group, CERN
2Beams Department, Accelerators and Beam Physics Group, CERN
3Experimental Physics Department, Safety Office, CERN
4Beams Department, Controls Group, CERN
5Information Technology Department, Collaboration, Devices & Applications Group, CERN
6Norwegian University of Science and Technology (NTNU)
A. Henriques, M. Andreini, G. Azzopardi, J. Devine, P. Elson, N. Mounet, M. Kongstein, N. Tarocco. CARA - COVID Airborne Risk Assessment tools. CERN (2021).
A risk assessment tool which simulates the long range airborne spread of the SARS-CoV-2 virus for space managers.
A tool to interact with various parameters of the CARA model.
CARA has not undergone review, approval or certification by competent authorities, and as a result, it cannot be considered as a fully endorsed and reliable tool, namely in the assessment of potential viral emissions from infected hosts to be modelled.
The software is provided "as is", without warranty of any kind, express or implied, including but not limited to the warranties of merchantability, fitness for a particular purpose and non-infringement. In no event shall the authors or copyright holders be liable for any claim, damages or other liability, whether in an action of contract, tort or otherwise, arising from, out of or in connection with the software or the use or other dealings in the software.
The easiest way to run a version of CARA Calculator is to use docker. A pre-built image of CARA is made available at https://gitlab.cern.ch/cara/cara/container_registry. In order to run cara locally with docker, run the following:
$ docker run -it -p 8080:8080 gitlab-registry.cern.ch/cara/cara/calculator
This will start a local version of CARA, which can be visited at http://localhost:8080/.
The CARA repository makes use of Git's Large File Storage (LFS) feature. You will need a working installation of git-lfs in order to run CARA in development mode. See https://git-lfs.github.com/ for installation instructions.
git lfs pull # Fetch the data from LFS
pip install -e . # At the root of the repository
python -m cara.apps.calculator
To run with the CERN theme:
python -m cara.apps.calculator --theme=cara/apps/templates/cern
To run the calculator on a different URL path:
python -m cara.apps.calculator --prefix=/mycalc
voila cara/apps/expert/cara.ipynb --port=8080
Then visit http://localhost:8080.
pip install -e .[test]
pytest ./cara
Simulate the docker build that takes place on openshift with:
s2i build file://$(pwd) --copy --keep-symlinks --context-dir ./app-config/nginx/ centos/nginx-112-centos7 cara-nginx-app
docker build . -f ./app-config/cara-webservice/Dockerfile -t cara-webservice
docker build ./app-config/auth-service -t auth-service
Get the client secret from the CERN Application portal for the cara-test app. See CERN-SSO-integration for more info.
read CLIENT_SECRET
Define some env vars (copy/paste):
export COOKIE_SECRET=$(openssl rand -hex 50)
export OIDC_SERVER=https://auth.cern.ch/auth
export OIDC_REALM=CERN
export CLIENT_ID=cara-test
export CLIENT_SECRET
Run docker-compose:
cd app-config
CURRENT_UID=$(id -u):$(id -g) docker-compose up
Then visit http://localhost:8080/.
The https://cern.ch/cara application is running on CERN's OpenShift platform. In order to set it up for the first time, we followed the documentation at https://cern.service-now.com/service-portal?id=kb_article&n=KB0004498. In particular we:
- Added the OpenShift application deploy key to the GitLab repository
- Created a Python 3.6 (the highest possible at the time of writing) application in OpenShift
- Configured a generic webhook on OpenShift, and call that from the CI of the GitLab repository
We have a replica of https://cara.web.cern.ch running on http://test-cara.web.cern.ch. Its purpose is to simulate what will happen when
a feature is merged. To push your changes to test-cara, simply push your branch to live/test-cara and the CI pipeline will trigger the
deployment. To push to this branch, there is a good chance that you will need to force push - you should always force push with care and
understanding why you are doing it. Syntactically, it will look something like (assuming that you have "upstream" as your remote name,
but it may be origin if you haven't configured it differently):
git push --force upstream name-of-local-branch:live/test-cara
First, get the oc client and then login:
$ oc login https://api.paas.okd.cern.chThen, switch to the project that you want to update:
$ oc project cara-testCreate a new service account in OpenShift to use GitLab container registry:
$ oc create serviceaccount gitlabci-deployer
serviceaccount "gitlabci-deployer" created
$ oc policy add-role-to-user registry-editor -z gitlabci-deployer
# We will refer to the output of this command as `test-token`
$ oc serviceaccounts get-token gitlabci-deployer
<...test-token...>Add the token to GitLab to allow GitLab to access OpenShift and define/change image stream tags. Go to Settings -> CI / CD -> Variables -> click on Expand button and create the variable OPENSHIFT_TEST_DEPLOY_TOKEN: insert the token <...test-token...>.
Then, create the webhook secret to be able to trigger automatic builds from GitLab.
Create and store the secret. Copy the secret above and add it to the GitLab project under CI /CD -> Variables with the name OPENSHIFT_TEST_WEBHOOK_SECRET.
$ WEBHOOKSECRET=$(openssl rand -hex 50)
$ oc create secret generic \
--from-literal="WebHookSecretKey=$WEBHOOKSECRET" \
gitlab-cara-webhook-secretFor CI usage, we also suggest creating a service account:
oc create sa gitlab-config-checkerUnder User Management -> RoleBindings create a new RoleBinding to grant View access to the gitlab-config-checker service account:
- name:
gitlab-config-checker-view-role - role name:
view - service account:
gitlab-config-checker
To get this new user's authentication token go to User Management -> Service Accounts -> gitlab-config-checker and locate the token in the newly created secret associated with the user (in this case gitlab-config-checker-token-XXXX). Copy the token value from Data.
Create the various configurations:
$ cd app-config/openshift
$ oc process -f configmap.yaml | oc create -f -
$ oc process -f services.yaml | oc create -f -
$ oc process -f imagestreams.yaml | oc create -f -
$ oc process -f buildconfig.yaml --param GIT_BRANCH='live/test-cara' | oc create -f -
$ oc process -f deploymentconfig.yaml --param PROJECT_NAME='cara-test' | oc create -f -The SSO integration uses OpenID credentials configured in CERN Applications portal. How to configure the application:
- Application Identifier:
cara-test - Homepage:
https://test-cara.web.cern.ch - Administrators:
cara-dev - SSO Registration:
- Protocol:
OpenID (OIDC) - Redirect URI:
https://test-cara.web.cern.ch/auth/authorize - Leave unchecked all the other checkboxes
- Protocol:
- Define new roles:
- Name:
CERN Users- Role Identifier:
external-users - Leave unchecked checkboxes
- Minimum Level Of Assurance:
CERN (highest) - Assign role to groups:
cern-accounts-primarye-group
- Role Identifier:
- Name:
External accounts- Role Identifier:
admin - Leave unchecked checkboxes
- Minimum Level Of Assurance:
Any (no restrictions) - Assign role to groups:
cara-app-external-accesse-group
- Role Identifier:
- Name:
Allowed users- Role Identifier:
allowed-users - Check
This role is required to access my application - Minimum Level Of Assurance:
Any (no restrictions) - Assign role to groups:
cern-accounts-primaryandcara-app-external-accesse-groups
- Role Identifier:
- Name:
Copy the client id and client secret and use it below.
$ COOKIE_SECRET=$(openssl rand -hex 50)
$ oc create secret generic \
--from-literal="CLIENT_ID=$CLIENT_ID" \
--from-literal="CLIENT_SECRET=$CLIENT_SECRET" \
--from-literal="COOKIE_SECRET=$COOKIE_SECRET" \
auth-service-secretsIf you need to update existing configuration, then modify this repository and after having logged in, run:
$ cd app-config/openshift
$ oc process -f configmap.yaml | oc replace -f -
$ oc process -f services.yaml | oc replace -f -
$ oc process -f imagestreams.yaml | oc replace -f -
$ oc process -f buildconfig.yaml --param GIT_BRANCH='live/test-cara' | oc replace -f -
$ oc process -f deploymentconfig.yaml --param PROJECT_NAME='cara-test' | oc replace -f -Be aware that if you create/recreate the environment you must manually create a route in OpenShift, specifying the respective annotation to be exposed outside CERN.