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merge(maps...) combines all given maps or objects into one. When multiple arguments contain the same key, the value from the last argument wins.

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Signature

merge(maps... map) map

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Example

Start with a base set of environment variables and override specific values for the production environment: 
variable "env" {
  description = "Target environment"
  type        = string
  default     = "staging"
}

computed "config" {
  description = "Merged environment configuration"
  expression  = merge(
    {
      LOG_LEVEL    = "info"
      CACHE_TTL    = "300"
      MAX_WORKERS  = "4"
    },
    var.env == "production" ? {
      LOG_LEVEL   = "warn"
      MAX_WORKERS = "16"
    } : {}
  )
}

task "run" {
  description = "Start the application with the merged config"
  commands = [
    "LOG_LEVEL=${computed.config["LOG_LEVEL"]} MAX_WORKERS=${computed.config["MAX_WORKERS"]} ./bin/app",
  ]
}
In production, LOG_LEVEL is warn and MAX_WORKERS is 16. In staging, both use the base defaults.

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Notes

  • Later arguments override keys from earlier arguments when there are conflicts.
  • merge accepts maps and objects. When merging maps, all maps must have the same value type.
  • merge does not perform deep merging. Nested values are replaced entirely, not merged recursively.