fabric8-analytics / fabric8-analytics-scaler

Service that scales workers based on SQS queue size

fabric8-analytics-worker-scaler

OpenShift service that scales fabric8-analytics workers based on number of messages in SQS. This service directly uses oc command-line tool to scale the deployment. This requires to have mounted service account inside the container. workerscaler service account for that purpose by default. Definitions and role binding of the service account are available in the openshift/ directory.

Configuration

The service needs to be configured via environment variables. The list of variables recognized by the service follows.

DC_NAME

Name of the deployment config to scale. Default value: bayesian-worker-ingestion

DEFAULT_REPLICAS

Default (minimum) number of replicas. Default value: 1

MAX_REPLICAS

Max number of replicas. Default value: 2

SQS_QUEUE_NAME

Name of the queue to monitor (without deployment prefix). Default value: ingestion_bayesianFlow_v0,ingestion_bayesianPackageFlow_v0

OC_PROJECT

Name of the project in OpenShift where to apply the changes. Default value: bayesian-preview

SCALE_COEF

Number of messages that singe worker is able to process, i.e. no need to spawn additional pods. Default value: 100

SLEEP_INTERVAL

Interval, in minutes, how often to run the scaler. Default value: 5

DRY_RUN

Run in dry-run mode, do not scale anything. Default value: false

The default values can be tweaked directly in the template. The values for specific deployments (staging, production) can be set in openshiftio/saas-analytics repository.

Deployment on openshift

OpenShift deployment information is located at openshift directory.

Footnotes

Check for all possible issues

The script named check-all.sh that is stored in the qa subdirectory is to be used to check the sources for all detectable errors and issues. This script can be run w/o any arguments:

./check-all.sh

Expected script output:

Running all tests and checkers
  Check all BASH scripts
    OK
  Check documentation strings in all Python source file
    OK
  Detect common errors in all Python source file
    OK
  Detect dead code in all Python source file
    OK
  Run Python linter for Python source file
    OK
  Unit tests for this project
    OK
Done

Overal result
  OK

An example of script output when one error is detected:

Running all tests and checkers
  Check all BASH scripts
    Error: please look into files check-bashscripts.log and check-bashscripts.err for possible causes
  Check documentation strings in all Python source file
    OK
  Detect common errors in all Python source file
    OK
  Detect dead code in all Python source file
    OK
  Run Python linter for Python source file
    OK
  Unit tests for this project
    OK
Done

Overal result
  One error detected!

Please note that the script creates bunch of *.log and *.err files that are temporary and won't be commited into the project repository.

Coding standards

• Local setup instructions and files can be found at local-setup directory, in case anyone wants local DynamoDB support. Note that, the container images used in the backup directory are not the same that are used to host the project in OpenShift. This directory should be removed once the local development support for DynamoDB makes its way in the current master branch.

• For any queries related to building of container images on registry.centos.org, or if some modifications are required in the Dockerfiles, then the CentOS Container Pipeline team can be contacted on the container-build channel under CentOS on Mattermost.

• For any queries regarding deployment of the application on OpenShift, contact the Deploy team at [e-mail] or at devtools-deploy channel under RH-DevTools on Mattermost.

• You can use scripts run-linter.sh and check-docstyle.sh to check if the code follows PEP 8 and PEP 257 coding standards. These scripts can be run w/o any arguments:

./run-linter.sh
./check-docstyle.sh

The first script checks the indentation, line lengths, variable names, white space around operators etc. The second script checks all documentation strings - its presence and format. Please fix any warnings and errors reported by these scripts.

List of directories containing source code, that needs to be checked, are stored in a file directories.txt

Code complexity measurement

The scripts measure-cyclomatic-complexity.sh and measure-maintainability-index.sh are used to measure code complexity. These scripts can be run w/o any arguments:

./measure-cyclomatic-complexity.sh
./measure-maintainability-index.sh

The first script measures cyclomatic complexity of all Python sources found in the repository. Please see this table for further explanation how to comprehend the results.

The second script measures maintainability index of all Python sources found in the repository. Please see the following link with explanation of this measurement.

You can specify command line option --fail-on-error if you need to check and use the exit code in your workflow. In this case the script returns 0 when no failures has been found and non zero value instead.

Dead code detection

The script detect-dead-code.sh can be used to detect dead code in the repository. This script can be run w/o any arguments:

./detect-dead-code.sh

Please note that due to Python's dynamic nature, static code analyzers are likely to miss some dead code. Also, code that is only called implicitly may be reported as unused.

Because of this potential problems, only code detected with more than 90% of confidence is reported.

List of directories containing source code, that needs to be checked, are stored in a file directories.txt

Common issues detection

The script detect-common-errors.sh can be used to detect common errors in the repository. This script can be run w/o any arguments:

./detect-common-errors.sh

Please note that only semantical problems are reported.

List of directories containing source code, that needs to be checked, are stored in a file directories.txt

Check for scripts written in BASH

The script named check-bashscripts.sh can be used to check all BASH scripts (in fact: all files with the .sh extension) for various possible issues, incompatibilities, and caveats. This script can be run w/o any arguments:

./check-bashscripts.sh

Please see the following link for further explanation about, how the ShellCheck works and which issues can be detected.