hclapi

hclapi is a lightweight, declarative API runtime powered by HashiCorp HCL.

Define HTTP endpoints, input validation schemas, database queries, caching, sandboxed data transformations, real-time streams, and OpenAPI 3.1 specifications in human-readable manifests without writing boilerplate backend routing code.

Manifests are verified and precompiled at startup, then executed sequentially at request time.

Documentation · Quickstart · Examples

Example

server {
  host = "0.0.0.0"
  port = 8080
}

connection "sql" "main" {
  engine = "postgres"
  source = env("DATABASE_URL")
}

route "POST /users" {
  request {
    body {
      field "email" {
        type     = string
        format   = "email"
        required = true
      }

      field "name" {
        type     = string
        required = true
      }
    }
  }

  sql "create" {
    connection = "main"

    query = <<-SQL
      INSERT INTO users (email, name)
      VALUES (@email, @name)
      RETURNING id, email, name
    SQL

    args = {
      email = ctx.request.body.email
      name  = ctx.request.body.name
    }

    catch {
      code   = "23505"
      status = 409
      body   = problem(409, "Email is already registered")
    }
  }

  respond {
    status = 201
    body   = steps.create.row
  }
}

Go integration

hclapi is also distributed as an embeddable Go library:

package main

import (
 "log"
 "net/http"

 "github.com/ju4n97/hclapi"
)

func main() {
  manifest, err := hclapi.Load("routes/*.hcl")
  if err != nil {
    log.Fatal(err)
  }

  app, err := hclapi.New(manifest)
  if err != nil {
    log.Fatal(err)
  }
  defer app.Close()

  http.ListenAndServe(":8080", app)
}

Custom Go behavior can be registered with hclapi.WithStep. See the Go integration guide for details.

Install

Install the standalone CLI daemon via go install:

go install github.com/ju4n97/hclapi/cmd/hclapi@latest

Or use precompiled binary archives, Linux packages (.deb, .rpm, .apk, .pkg.tar.zst), and container images documented in the installation guide.

Documentation

See the full hclapi documentation.

Contributing

See CONTRIBUTING.md.

License

MIT