Kron - Command line utility for Kronbute

This is the repository for Kron, a command line utility for Kronbute job manager.

Why kron?

Well, when I was developing Kronbute, the automatic scheduled job manager for Healthcare.com ETL processes, I got stuck making the UI for the application, I am not really creative with UI development in Javascript and I had another two projects to work on at the same time, so I decided to throw away the current UI to develop it later and create a simple command line utility to handle Kronbute jobs, this is the product of that love.

What can I do with Kron?

Basically everything Kronbute allows you to do:

• Create a job to run under a schedule in Kronbute
• List all available jobs in Kronbute
• Display details about a Kronbute job
• Edit or modify a Kronbute job
• Delete a Kronbute job

More functionality will be available soon together with Kronbute development.

What commands are available?

In general, a Kron command looks like this:

kron <area> <verb> [options]

Where <area> is any of job or runs, depending on what area you want to work on, for example, job is for job related operations: list, create, edit, delete are verbs for the job command. Some commands use specific options.

The available verbs for the area job are:

• list, list all current jobs in Kronbute, available options are

• view [jobid], view details of a job with id jobid

• create, create a new job, it will ask for the following options if not provided:

  • --name, the name of the job
  • --timezone, optional, the timezone name to run the job on, by default is UTC, timezones looks like "America/New_York"
  • --image, the docker image to run the job
  • --tag, the docker image tag to run the job
  • --group or -g, this is optional, the list of environment groups to use with this job
  • --schedule, this is the cron schedule to run the job
  • --entrypoint, the image entry point to execute, optional
  • --alias, an alias name to know the job, it must be unique, optional
  • --environment or -e, this is optional, the list of environment variables to set the job to run, pass it in the form key=value, for example -e key=value1 -e key2=value2
  • --env-file, optional, environment file, each line contains a line in the form key=value with the environment variables to pass to the process, use when you have repetitive environment variables between jobs.

• edit, edit a job, you need to pass the job id (--id) and it will request the same arguments as create (if not passed as command line arguments)

• delete, removes a job, you need to pass the job id with --id, for example, kron job delete --id 5 will remove job with id 5, it will ask you yes/no before delete, pass --yes if you are sure you want to delete the job without any confirmation.

The available verbs for the area group are:

• list, list all existing environment groups
• view [groupid], view an environment group details
• create, create an environment group
  • --name, unique name for the environent group, case sensitive
  • --environment or -e, the list of environment variables to set, optional
  • --env-file, environment file to load environment variables
• edit [groupid], edit an existing environment group, same parameters as create
• delete [groupid], delete an existing evironment group

How do I install Kron?

Kron is a Python 3 application, so first make sure you have python installed. You can install Kron using pip:

pip install git+https://github.com/cprieto/kron.git

How do I upgrade Kron?

Again, this is easy using Pip:

pip install --upgrade git+https://github.com/cprieto/kron.git

Kron is failing with something regarding the server, what could be wrong?

You need to tell Kron where is your Kronbute server, by default is pointing to localhost:8080, if you want to test another server, you have two options:

• Pass the parameter --server with the address for the server, for example kron --server http://anotherserver.com job list
• Set the environment variable KRONBUTE_SERVER with the address of the server

How do I know what version am I running?

For this we have the noun version, this will display in a nice way the version of the tool and Kronbute server we are connecting to.

kron info

Using an import file

Instead of creating or edit a job using the command line you can load one or all yoru values from a YAML file, an example of a job YAML file:

name: Sample job
alias: sample_job
image: hc/data-integration-job:latest
schedule: '*/5 * * * *'
timezone: UTC
groups:
  - sample_group_1
  - sample_group_2
entrypoint: python3 main.py

environment:
  VARIABLE1: VALUE1
  VARIABLE2:

Notice the way we declare the image and tag, there is no separate entry for image and tag but it is declared in the docker way, image:tag, as in the command line, if no tag is declared, the default latest is used.

Use the --import option when creating or editing a file with an existing YAML file with the job definition (or partial job definition):

kron job create --import sample.yml

You can declare a partial file, only with the attributes you are insterested to use/edit and pass the rest from the command line, for example, you can use a file with the environment variables but pass the name from the command line.

The relevance order is command line > yaml file, it means, if you declare the name in the YAML file but as well pass it with the --name option, the option from the command line will have preference over the YAML file name, this is a very flexible way to declare options for edit, for example.

Remember YAML files are very delicate with tabs and spaces, read more about YAML syntax at this Wikipedia page

IMPORTANT Currently there is a bug with the way we specify YAML and environment variables all together see, so if you provide YAML and the environment variable parameter at the same time it will use only the parameters from the command line.

Export one job

Now we have the export verb for the job noun, we can export to standard output the details of a job so we can recreate that job, for example:

kron job export 1

Will export the data for the job 1 to the standard output, to save it into a file you can redirect the output to a file:

kron job export 1 > some_file.yml

You can use the alias name for the job or the id, it won't matter.