Docker Container Cron Alternative With Jobber.
| Bundle | Version | Tags | Dockerfile | Readme | Example |
|---|---|---|---|---|---|
| Jobber | latest, v1.2 | latest, v1.2 | Dockerfile | Readme | blacklabelops/jobber:latest |
| Jobber + Tools | latest, v1.2 | tools, tools.v1.2 | Dockerfile | blacklabelops/jobber:tools | |
| Jobber + Docker Tools | latest | docker, docker.v1.2 | Dockerfile | Readme | blacklabelops/jobber:docker |
| Jobber + AWS Cli | latest, v1.2 | aws, tools.v1.2 | Dockerfile | Readme | blacklabelops/jobber:aws |
| Jobber + GCE Cli | latest, v1.2 | gce, gce.v1.2 | Dockerfile | Readme | blacklabelops/jobber:gce |
| Jobber + All Above | latest, v1.2 | cloud, cloud.v1.2 | Dockerfile | Readme | blacklabelops/jobber:cloud |
AWS = Amazon Web Services, GCE = Google Cloud Engine
In short, you can define periodic tasks for an arbitrary number of jobs.
Example:
$ docker run -d \
--name jobber \
-e "JOB_NAME1=TestEcho" \
-e "JOB_COMMAND1=echo hello world" \
blacklabelops/jobber
Will print "hello world" to console every second.
The environment variables are numerated. Just add the number behind the environment variable and the container will create a job definition for Jobber!
This way the container can handle an arbitrary number of jobs without file handling or cumbersome syntax!
Example with two tasks:
$ docker run -d \
--name jobber \
-e "JOB_NAME1=TestEcho" \
-e "JOB_COMMAND1=echo hello world" \
-e "JOB_NAME2=TestEcho" \
-e "JOB_COMMAND2=echo hello moon" \
blacklabelops/jobber
First job will print "hello world" and then second job will print "hello moon" to console every second.
Globally, there is a notify program defined, default one is sendmail, you can override it using an environment variable, JOBS_NOTIFY_CMD.
This program will receive a JSON payload as specified in the jobber docs
Every job definition is specified by up to four environment variables:
- JOB_NAME: The identifier for the job, must not contain empty spaces!
- JOB_COMMAND: The bash command to be executed.
- JOB_TIME: The cron schedule for the job. See Documentation
- JOB_ON_ERROR: How Jobber should act on errors. Values: Stop, Backoff, Continue (Default). See Documentation
- JOB_NOTIFY_ERR: If Jobber should notify on error. Values:
true,false. Default isfalse - JOB_NOTIFY_FAIL: If Jobber should notify on failure. Values:
true,false. Default isfalse
Full example:
$ docker run -d \
--name jobber \
-e "JOBS_NOTIFY_CMD=/bin/bash" \
-e "JOB_NAME1=TestEcho" \
-e "JOB_COMMAND1=echo hello world" \
-e "JOB_TIME1=1" \
-e "JOB_ON_ERROR1=Backoff" \
-e "JOB_NOTIFY_ERR1=true" \
-e "JOB_NOTIFY_FAIL1=true" \
blacklabelops/jobber
Will print "hello world" at second 1 of every minute.
When it comes to the cron string then Jobber is a little bit different. If you do not define any time then the resulting cron table will be
* * * * * *
and the job will be executed every second.
You can also define just one number "1". This will be interpreted as
1 * * * * *
Example:
$ docker run \
--name jobber \
-e "JOB_NAME1=TestEcho" \
-e "JOB_COMMAND1=echo hello world" \
-e "JOB_TIME1=1 * * * * *"
blacklabelops/jobber
Will print "hello world" every second.
so you ca 65F5 n see that you have to specify the time string from the back and the rest will be filled up by Jobber.
As a reminder, cron timetable is like follows:
- Token: Second
- Token: Minute
- Token: Hour
- Token: Day of Month
- Token: Month
- Token: Day of Week