Clojure

Detection

migetpacks detects a Clojure application when either of the following files is present in the project root:

project.clj (Leiningen)
deps.edn (Clojure CLI/tools.deps)

Version Detection

Clojure Version

Clojure version is resolved in the following priority order:

Source	Example
`.clojure-version`	`1.11.1`
`project.clj` (org.clojure/clojure dependency)	`[org.clojure/clojure "1.11.1"]`
`deps.edn` (org.clojure/clojure)	`org.clojure/clojure {:mvn/version "1.11.1"}`
Default	`1.11.1`

Leiningen Version

Leiningen version is detected from:

Source	Example
`project.clj` (`:min-lein-version`)	`:min-lein-version "2.11.2"`
Default	`2.11.2`

Java Version

The JDK version used for compilation and runtime is read from:

Source	Example
`system.properties`	`java.runtime.version=21`
Default	`21`

Build Process

migetpacks uses the official clojure:temurin-{java}-lein Docker image which includes Leiningen and the JDK:

# Build stage
FROM clojure:temurin-21-lein AS builder
WORKDIR /build

# Clojure build environment
ENV JAVA_TOOL_OPTIONS="-Dfile.encoding=UTF-8"
ENV LEIN_ROOT=1

# Layer caching: copy project.clj first
COPY project.clj ./

# Download dependencies (cached if project.clj unchanged)
RUN lein deps

# Copy source code
COPY . .

# Build uberjar and cleanup
RUN lein uberjar \
    && rm -rf src/ test/ dev/ resources/public/js/compiled

# Runtime stage
FROM eclipse-temurin:21-jre
WORKDIR /app
COPY --from=builder --chown=1000:1000 /build /app

Uberjar Detection

migetpacks detects custom uberjar names from project.clj:

(defproject myapp "1.0.0"
  :uberjar-name "myapp-standalone.jar"
  ...)

If :uberjar-name is specified, migetpacks uses it when configuring the run command.

Run Command

The default run command for Clojure applications:

java -jar target/uberjar/*-standalone.jar

Override with RUN_COMMAND or a Procfile:

web: java -jar target/uberjar/myapp-standalone.jar

JVM Configuration

The following environment variables are set for production:

Variable	Value
`JAVA_OPTS`	`-Dfile.encoding=UTF-8 -XX:MaxRAMPercentage=80.0 -Dclojure.main.report=stderr`
`JAVA_TOOL_OPTIONS`	`-Dfile.encoding=UTF-8`

Caching

Layer Caching

Dependencies are cached by copying project.clj before the full source:

Cached Files	Purpose
`project.clj`	Leiningen project definition with dependencies

Scenario	Dependency Install
First build	Runs
Source code change only	Cached
project.clj change	Runs

BUILD_CACHE_DIR

When BUILD_CACHE_DIR is set, Leiningen and Maven caches persist at:

Cache Path	Contents
lein cache	Leiningen profiles and plugins
m2 cache	Maven repository (`.m2`)

DHI Support

Docker Hardened Images are supported for Clojure runtime.

Clojure uses a hybrid approach: the official Clojure build image (which includes Leiningen) for building, and a DHI distroless image for runtime.

Stage	Image
Build	`clojure:temurin-{java}-lein` (official)
Runtime	`dhi.io/eclipse-temurin:{java}`

DHI Notes

The build image is always the official Clojure image (DHI does not provide Clojure/Leiningen images).
Only the runtime stage uses DHI distroless Eclipse Temurin JRE.
Java version is read from system.properties (default: 21).
Runtime images are distroless (no shell).

Example with DHI

docker run --rm \
  -v /path/to/clojure-app:/workspace/source \
  -v /var/run/docker.sock:/var/run/docker.sock \
  -e OUTPUT_IMAGE=my-clojure-app:latest \
  -e USE_DHI=true \
  miget/migetpacks:latest

Example

docker run --rm \
  -v /path/to/clojure-app:/workspace/source \
  -v /var/run/docker.sock:/var/run/docker.sock \
  -e OUTPUT_IMAGE=my-clojure-app:latest \
  miget/migetpacks:latest

With custom JVM options

docker run --rm \
  -v /path/to/clojure-app:/workspace/source \
  -v /var/run/docker.sock:/var/run/docker.sock \
  -e OUTPUT_IMAGE=my-clojure-app:latest \
  -e JAVA_OPTS="-Xmx1g -Dclojure.main.report=stderr" \
  miget/migetpacks:latest

Getting Started

Guides

Configuration

Languages

Deploying

Reference

Detection

Version Detection

Clojure Version

Leiningen Version

Java Version

Build Process

Uberjar Detection

Run Command

JVM Configuration

Caching

Layer Caching

BUILD_CACHE_DIR

DHI Support

DHI Notes

Example with DHI

Example

With custom JVM options

​Detection

​Version Detection

​Clojure Version

​Leiningen Version

​Java Version

​Build Process

​Uberjar Detection

​Run Command

​JVM Configuration

​Caching

​Layer Caching

​BUILD_CACHE_DIR

​DHI Support

​DHI Notes

​Example with DHI

​Example

​With custom JVM options

Detection

Version Detection

Clojure Version

Leiningen Version

Java Version

Build Process

Uberjar Detection

Run Command

JVM Configuration

Caching

Layer Caching

BUILD_CACHE_DIR

DHI Support

DHI Notes

Example with DHI

Example

With custom JVM options