References

Errand uses a simple dot-notation to reference named entities in a playbook. When you reference a block, Errand automatically ensures it runs before any block that depends on it.

Syntax

Reference	Refers to
`var.<name>`	A declared `variable` block
`computed.<name>`	A declared `computed` block
`task.<name>`	A declared `task` block

Where you can use references

In task commands

variable "version" {
  type = string
}

task "tag" {
  commands = [
    "git tag v${var.version}",
    "git push origin v${var.version}",
  ]
}

In computed expressions

variable "app" {
  type    = string
  default = "api"
}

computed "image" {
  expression = "${env("CI_REGISTRY", "registry.example.com")}/${var.app}"
}

In task conditions

variable "deploy" {
  type    = bool
  default = true
}

task "deploy" {
  condition = var.deploy
  commands  = ["./bin/deploy"]
}

In depends_on

depends_on takes a list of task.<name> references:

task "deploy" {
  depends_on = [task.build, task.test]
  commands   = ["./bin/deploy"]
}

Implicit vs explicit dependencies

Errand infers dependencies from references. If a task command uses var.version, Errand knows the variable must be resolved before the task runs. You do not need to list variables in depends_on. Use depends_on when the dependency is not expressed in a command or condition, such as an aggregate task:

task "ci" {
  depends_on = [task.lint, task.test, task.build]
  commands   = []
}

Cycle detection

Errand detects circular dependencies before execution begins and reports a Cyclic dependency error. Fix cycles by breaking the dependency chain or restructuring tasks.

Undefined references

Referencing a name that does not exist is an Undefined reference error. Errand validates all references before running any task.

Getting started

Playbook

Syntax

CLI

Syntax

Where you can use references

In task commands

In computed expressions

In task conditions

In depends_on

Implicit vs explicit dependencies

Cycle detection

Undefined references

​Syntax

​Where you can use references

​In task commands

​In computed expressions

​In task conditions

​In depends_on

​Implicit vs explicit dependencies

​Cycle detection

​Undefined references

Syntax

Where you can use references

In task commands

In computed expressions

In task conditions

In depends_on

Implicit vs explicit dependencies

Cycle detection

Undefined references