Kubes Hooks

Hook Generator

To generator a starter hook:

$ kubes new hook kubes
      create  .kubes/config/hooks/kubes.rb

You can use hooks to run scripts at specific steps of the kubes deploy lifecycle.

Lifecycle Hooks

Hook Description
compile When kubes compiles the .kubes/resources to .kubes/output.
apply When kubes runs all the kubectl apply commands.
delete When kubes runs all the kubectl delete commands.
prune When kubes prunes. IE: To clean old secrets.

Kubes Lifecyle Level

These lifecycle points occur at a higher-level than the kubectl commands. Here’s an example to help explain:

$ kubes apply
=> kubectl apply -f .kubes/output/shared/namespace.yaml
=> kubectl apply -f .kubes/output/web/service.yaml
=> kubectl apply -f .kubes/output/web/deployment.yaml
$

Kubes calls out to kubectl apply 3 times for each resource kind.

The kubes hooks run before and after all the kubectl apply commands. So the hook only runs once.

$ kubes apply
# kubes apply before hook <= HERE
=> kubectl apply -f .kubes/output/shared/namespace.yaml
=> kubectl apply -f .kubes/output/web/service.yaml
=> kubectl apply -f .kubes/output/web/deployment.yaml
# kubes apply after hook  <= HERE
$

Example

.kubes/config/hooks/kubes.rb

before("apply",
  execute: "echo 'kubes before apply hook'",
)

after("apply",
  execute: "echo 'kubes after apply hook'",
)

Example results:

$ kubes apply
Running kubes before apply hook.
=> echo 'kubes before apply hook'
kubes before apply hook
=> kubectl apply -f .kubes/output/shared/namespace.yaml
=> kubectl apply -f .kubes/output/web/service.yaml
=> kubectl apply -f .kubes/output/web/deployment.yaml
Running kubes after apply hook.
=> echo 'kubes after apply hook'
kubes after apply hook
$

General Form

before(COMMAND_NAME, OPTIONS)

The command name corresponds to the kubes commands: apply, delete, etc.

Hook Options

Name Description
label A human-friendly label so you can see what hooks is being run.
execute The script or command to run. IE: path/to/some/script.sh
exit_on_fail Whether or not to continue process if the script returns an failed exit code.

Ruby Hooks

Instead of using a script for the hook execute option, you can also use a Ruby object. This provides some more control over the current process. See: Ruby Hooks