#Types and schema constraints

hclapi features a strongly typed schema and configuration system. Types are verified at boot time during manifest parsing and enforced at request ingress before pipeline execution.

#Schema data types

Used inside schema and request field definitions (field "<name>" { type = <type> }):

#Examples

schema "product" {
  field "sku" {
    type = string,
    required = true
  }
  field "price" {
    type = float,
    required = true,
    min = 0.01
  }
  field "tags" {
    type = list(string),
    default = []
  }
  field "metadata" {
    type = map(any)
  }
}

#Scalar configuration types

hclapi provides specialized scalar types that parse human-readable strings into typed units at startup and fail fast on invalid syntax.

#Duration

Backed by Go's time.Duration.

Units can be combined (e.g. "1h30m", "2m45s").

#Usage in manifests:

server {
  read_timeout = "30s"
  idle_timeout = "2m"
}

connection "postgres" "main" {
  pool {
    conn_max_lifetime = "1h"
    idle_timeout      = "10m"
  }
}

#ByteSize

Backed by a 64-bit integer representing byte quantities. Both decimal (1,000-based) and binary (1,024-based) units are accepted case-insensitively.

Fractional quantities and raw integer bytes are both supported:

server {
  max_body_size = "25MB"    # 25,000,000 bytes
  max_body_size = "2.5MiB"  # 2,621,440 bytes
  max_body_size = "1048576" # 1,048,576 raw integer bytes
}

#Compile-time diagnostics

Invalid type or scalar formats fail fast during hclapi serve boot:

server {
  read_timeout = "100years"
}

error: server: invalid read_timeout: invalid duration "100years": time: unknown unit "years" in duration "100years"

server {
  max_body_size = "10XB"
}

error: server: invalid max_body_size: invalid byte size "10XB": unknown unit "XB"