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Lua on Miren

Lua isn't auto-detected, so you deploy it with a Dockerfile.miren. This guide uses lua-http — a proper Lua HTTP server — installed with LuaRocks. (For a heavier stack, OpenResty (nginx + Lua) works too.)

Let your agent do this

Ask your AI coding agent to "set up this Lua app on Miren" after installing the Miren agent skills. It adds the Dockerfile.miren, binds the server to 0.0.0.0:$PORT, and deploys — using this page as its reference.

Do you need a Dockerfile?​

Yes. Miren doesn't auto-detect Lua, so add a Dockerfile.miren to your project root. Miren builds from it instead of guessing the stack — see Using Dockerfile.miren.

Want native support?

Miren auto-detects and builds common stacks (Python, Node, Bun, Go, Ruby, Rust) without a Dockerfile. This language isn't one of them yet — if you'd like first-class support, request it.

Bind to the injected port​

Miren injects PORT and routes traffic to it, so read PORT and bind 0.0.0.0. With lua-http:

local server = require "http.server"
local headers = require "http.headers"

local port = tonumber(os.getenv("PORT") or "8080")

local function on_stream(_, stream)
  stream:get_headers()
  local res = headers.new()
  res:append(":status", "200")
  res:append("content-type", "text/plain")
  stream:write_headers(res, false)
  stream:write_chunk("Hello from Lua on Miren!\n", true)
end

local s = assert(server.listen {
  host = "0.0.0.0",
  port = port,
  onstream = on_stream,
})
assert(s:listen())
print("listening on 0.0.0.0:" .. port)
assert(s:loop())

The Dockerfile​

Create Dockerfile.miren in your project root. LuaRocks builds lua-http and its C dependencies (cqueues, luaossl), so the image needs a compiler and OpenSSL headers:

FROM debian:12-slim
RUN apt-get update -y \
    && apt-get install -y lua5.4 liblua5.4-dev luarocks gcc make m4 libssl-dev git \
    && rm -rf /var/lib/apt/lists/*
WORKDIR /app
RUN luarocks --lua-version=5.4 install http
COPY . /app
EXPOSE 8080
Pin the Lua version for LuaRocks

Debian's luarocks can target several Lua versions. Pass --lua-version=5.4 (matching the lua5.4/liblua5.4-dev packages) so the rock and its C parts build against the same interpreter you run with.

.dockerignore​

.git

Set up the app​

Even with a Dockerfile.miren, Miren needs at least one service defined — it doesn't use the image's CMD as the start command. Add a Procfile:

web: lua5.4 /app/app.lua

Then create .miren/app.toml naming your app and deploy from your project root:

name = "lua-bench"
miren deploy
Deploying without a service fails

If no service is defined, the build succeeds but the deploy stops with no services defined: please define at least one service in a Procfile or .miren/app.toml.

Environment variables​

Set variables with miren env set — -e for plain values, -s for secrets (masked in output and logs). Read them with os.getenv("KEY"):

miren env set -e LOG_LEVEL=info
miren env set -s API_TOKEN

See App Configuration — Environment Variables.

Agent quick reference​

  • Detection: none — requires Dockerfile.miren
  • Library: lua-http via luarocks --lua-version=5.4 install http (needs gcc make m4 libssl-dev)
  • Service is required: define a Procfile (web: lua5.4 /app/app.lua) — the image CMD is not used
  • Port: os.getenv("PORT"); server.listen { host = "0.0.0.0", port = port }
  • Env vars: miren env set -e/-s; read with os.getenv
  • Heavier option: OpenResty (nginx + Lua) for a production Lua web stack

Next steps​