CODEWITHSUNDEEP
configurationamazon-web-servicesprovisioningamazon-elastic-beanstalk
Gabe Kopley
Gabe Kopley

Reputation: 16677

Where to put Elastic Beanstalk config commands that are only run once on spin-up?

I know I can put commands in my source code in .ebextensions/*.config using the commands array. These are executed on every deploy however. What about if I want to execute a configuration command only once when spinning up a new instance?

Upvotes: 20

Views: 4583

Answers (2)

jmosbech
jmosbech

Reputation: 1128

On Windows this should work:

commands:
  01-do-always:
    command: run_my_script
  02-do-on-boot:
    command: script_to_run_once
    test: cmd /c "if exist c:\\semaphore.txt (exit 1) else (exit 0)"
  99-signal-startup-complete:
    command: echo %date% %time% > c:\\semaphore.txt

Note that I had to change the test command from Jim Flanagan's answer.

Upvotes: 0

Jim Flanagan
Jim Flanagan

Reputation: 2129

Commands can be run conditionally using the test: modifier. You specify a test to be done. If the test returns 0, the command is run, otherwise it is not.

If the last command in your config file touches a file, and the commands above that you only want to run once check for the existence of that file, then those commands will only run the first time.

commands:
  01-do-always:
    command: run_my_script
  02-do-on-boot:
    command: script_to_run_once
    test: test ! -f .semaphore
  99-signal-startup-complete:
    command: touch .semaphore

On Windows it would be something like this

commands:
  01-do-always:
    command: run_my_script
  02-do-on-boot:
    command: script_to_run_once
    test: if exists c:\\path\\to\\semaphore.txt (exit 0) else (exit 1)
  99-signal-startup-complete:
    command: date > c:\\path\\to\\semaphore.txt

Upvotes: 39

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