Summary
Wait for an entity to reach a specified state.
Usage
juju wait-for [options] <command> ...
Options
| Flag | Default | Usage |
|---|---|---|
--description |
false | Show short description of plugin, if any |
--h, --help
|
false | Show help on a command or other topic. |
Details
The wait-for set of commands (model, application, machine and unit) defines a way to wait for a goal state to be reached. The goal state can be defined programmatically using the query DSL (domain specific language).
The wait-for command is an optimized alternative to the status command for determining programmatically if a goal state has been reached. The wait-for command streams delta changes from the underlying database, unlike the status command which performs a full query of the database.
The query DSL is a simple language that can be comprised of expressions to produce a boolean result. The result of the query is used to determine if the goal state has been reached. The query DSL is evaluated against the scope of the command.
Built-in functions are provided to help define the goal state. The built-in functions are defined in the query package. Examples of built-in functions include len, print, forEach (lambda), startsWith and endsWith.
Examples:
Waits for the mysql/0 unit to be created and active.
juju wait-for unit mysql/0
Waits for the mysql application to be active or idle.
juju wait-for application mysql --query='name=="mysql" && (status=="active" || status=="idle")'
Waits for the model units to all start with ubuntu.
juju wait-for model default --query='forEach(units, unit => startsWith(unit.name, "ubuntu"))'
See also: wait-for model wait-for application wait-for machine wait-for unit