agilecreativity / clj-test-containers

A lightweight, inofficial wrapper around the Testcontainers Java library.

clj-test-containers

What it is

This library is a lightweight wrapper around the Testcontainers Java library.

What it isn't

This library does not provide tools to include testcontainers in your testing lifecycle. As there are many different test tools with different approaches to testing in the clojure world, handling the lifecycle is up to you.

Integration with test runners

There is an experimental kaocha plugin you can try out

Usage

The library provides a set of functions to interact with the testcontainers. A simple example, how to create a container with a Docker label, could look like this:

(require '[clj-test-containers.core :as tc])

(def container (-> (tc/create {:image-name    "postgres:12.1"
                               :exposed-ports [5432]
                               :env-vars      {"POSTGRES_PASSWORD" "verysecret"}})
                   (tc/bind-filesystem! {:host-path      "/tmp"
                                         :container-path "/opt"
                                         :mode           :read-only})
                   (tc/start!)))

(do-database-testing (:host container)
                     (get (:mapped-ports container) 5432))

(tc/stop! container)

If you'd rather create a container from a Dockerfile in your project, it could look like this:

(require '[clj-test-containers.core :as tc])

(def container (-> (tc/create-from-docker-file {:env-vars      {"FOO" "bar"}
                                                :exposed-ports [80]
                                                :docker-file   "resources/Dockerfile"})
                   (tc/start!)))

If you prefer to use prebuilt containers from the Testcontainers project, you can do it like this

(require '[clj-test-containers.core :as tc])
(:import [org.testcontainers.containers PostgreSQLContainer])

(def container (-> (tc/init {:container     (PostgreSQLContainer. "postgres:12.2")
                             :exposed-ports [5432]})
                   (tc/start!)))

Functions and Properties

create

Creates a testcontainers instance from a given Docker label and returns them

Config parameters:

Key	Type	Description
:image-name	String, mandatory	The name and label of an image, e.g. postgres:12.2
:exposed-ports	Vector with ints, mandatory	All ports which should be exposed and mapped to a local port
:env-vars	Map	A map with environment variables
:command	Vector with strings	The start command of the container
:network	Map	A map containing the configuration of a Docker Network (see: create-network)
:network-aliases	Map	A list of alias names for the container on the network
:wait-for	Map	A map containing the wait strategy to use and the condition to check for
:log-to	Map	A map containing the log strategy to use, e.g. {:log-strategy string}

Result:

Key	Type	Description
:container	org.testcontainers.containers.Container	The Testcontainers instance, accessible for everything this library doesn't provide (yet)
:exposed-ports	Vector with ints	Value of the same input parameter
:env-vars	Map	Value of the same input parameter
:host	String	The host for the Docker Container
:network	Map	The network configuration of the Container, if provided
:wait-for	Map	The wait-for configuration of the Container, if provided!

Example:

(create {:image-name      "alpine:3.2"
         :exposed-ports   [80]
         :env-vars        {"MAGIC_NUMBER" "42"}
         :network         (create-network)
         :network-aliases ["api-server"]
         :command         ["/bin/sh"
                           "-c"
                           "while true; do echo \"$MAGIC_NUMBER\" | nc -l -p 80; done"]})

Example using wait-for and healthcheck:

(create {:image-name      "alpine:3.2"
         :exposed-ports   [80]
         :env-vars        {"MAGIC_NUMBER" "42"}
         :network         (create-network)
         :network-aliases ["api-server"]
         :wait-for        {:strategy :health}
         :command         ["/bin/sh"
                           "-c"
                           "while true; do echo \"$MAGIC_NUMBER\" | nc -l -p 80; done"]})

init

Initializes a given Testcontainer, which was e.g. provided by a library

Config parameters:

Key	Type	Description
:container	org.testcontainers.containers.GenericContainer, mandatory	The name and label of an image, e.g. postgres:12.2
:exposed-ports	Vector with ints, mandatory	All ports which should be exposed and mapped to a local port
:env-vars	Map	A map with environment variables
:command	Vector with strings	The start command of the container
:network	Map	A map containing the configuration of a Docker Network (see: create-network)
:network-aliases	Map	A list of alias names for the container on the network
:wait-for	Map	A map containing the wait strategy to use and the condition to check for
:log-to	Map	A map containing the log strategy to use, e.g. {:log-strategy string}

Result:

Key	Type	Description
:container	org.testcontainers.containers.Container	The Testcontainers instance, accessible for everything this library doesn't provide (yet)
:exposed-ports	Vector with ints	Value of the same input parameter
:env-vars	Map	Value of the same input parameter
:host	String	The host for the Docker Container
:network	Map	The network configuration of the Container, if provided
:wait-for	Map	The wait-for configuration of the Container, if provided!

Example:

;; PostgreSQL container needs a separate library! This is not included.
(init {:container     (org.testcontainers.containers.PostgreSQLContainer)
       :exposed-ports [80]
       :env-vars      {"MAGIC_NUMBER" "42"}
       :command       ["/bin/sh"
                       "-c"
                       "while true; do echo \"$MAGIC_NUMBER\" | nc -l -p 80; done"]})

Example using wait-for and a log message:

;; PostgreSQL container needs a separate library! This is not included.
(init {:container     (org.testcontainers.containers.PostgreSQLContainer)
       :exposed-ports [80]
       :env-vars      {"MAGIC_NUMBER" "42"}
       :wait-for      {:strategy :log :message "accept connections"}
       :command       ["/bin/sh"
                       "-c"
                       "while true; do echo \"$MAGIC_NUMBER\" | nc -l -p 80; done"]})

create-from-docker-file

Creates a testcontainer from a Dockerfile

Config parameters:

Key	Type	Description
:docker-file	String, mandatory	String containing a path to a Dockerfile
:exposed-ports	Vector with ints, mandatory	All ports which should be exposed and mapped to a local port
:env-vars	Map	A map with environment variables
:command	Vector with strings	The start command of the container
:network	Map	A map containing the configuration of a Docker Network (see: create-network)
:network-aliases	Map	A list of alias names for the container on the network
:wait-for	Map	A map containing the wait strategy to use and the condition to check for
:log-to	Map	A map containing the log strategy to use, e.g. {:log-strategy string}

Result:

Key	Type	Description
:container	org.testcontainers.containers.Container	The Testcontainers instance, accessible for everything this library doesn't provide (yet)
:exposed-ports	Vector with ints	Value of the same input parameter
:env-vars	Map	Value of the same input parameter
:host	String	The host for the Docker Container
:network	Map	The network configuration of the Container, if provided
:wait-for	Map	The wait-for configuration of the Container, if provided!

Example:

(create-from-docker-file {:docker-file   "resources/Dockerfile"
                          :exposed-ports [5432]
                          :env-vars      {"MAGIC_NUMBER" "42"}
                          :command       ["/bin/sh"
                                          "-c"
                                          "while true; do echo \"$MAGIC_NUMBER\" | nc -l -p 80; done"]})

---

start!

Starts the Testcontainer, which was defined by create

Config parameters:

Key	Type	Description
First parameter:
container-config	Map, mandatory	Return value of the create function

Result:

Key	Type	Description
:container	org.testcontainers.containers.Container	The Testcontainers instance, accessible for everything this library doesn't provide (yet)
:exposed-ports	Vector with ints	Value of the same input parameter
:env-vars	Map	Value of the same input parameter
:host	String	The host for the Docker Container
:id	String	The ID of the started docker container
:mapped-ports	Map	A map containing the container port as key and the mapped local port as a value

Example:

(def container (create {:image-name    "alpine:3.2"
                        :exposed-ports [80]
                        :env-vars      {"MAGIC_NUMBER" "42"}}))

(start! container)

---

stop!

Stops the Testcontainer, which was defined by create

Config parameters:

Key	Type	Description
First parameter:
container-config	Map, mandatory	Return value of the create function

Result:

The container-config

Example:

(def container (create {:image-name    "alpine:3.2"
                        :exposed-ports [80]
                        :env-vars      {"MAGIC_NUMBER" "42"}}))

(start! container)
(stop! container)

---

map-classpath-resource!

Maps a resource from your classpath into the containers file system

Config parameters:

Key	Type	Description
First parameter:
container-config	Map, mandatory	Return value of the create function
Second parameter:
:resource-path	String, mandatory	Path of your classpath resource
:container-path	String, mandatory	Path, to which the resource should be mapped
:mode	Keyword, mandatory	:read-only or :read-write

Result:

The container-config

Example:

(map-classpath-resource! container {:resource-path  "test.sql"
                                    :container-path "/opt/test.sql"
                                    :mode           :read-only})

---

bind-filesystem!

Binds a path from your local filesystem into the Docker container as a volume

Config parameters:

Key	Type	Description
First parameter:
container-config	Map, mandatory	Return value of the create function
Second parameter:
:host-path	String , mandatory	Path on your local filesystem
:container-path	String, mandatory	Path, to which the resource should be mapped
:mode	Keyword, mandatory	:read-only or :read-write

Result:

The container-config

Example:

(bind-filesystem! container {:host-path      "."
                             :container-path "/opt"
                             :mode           :read-only})

---

copy-file-to-container!

Copies a file from your filesystem or classpath into the running container

Config parameters:

Key	Type	Description
First parameter:
container-config	Map, mandatory	Return value of the create function
Second parameter:
:path	String, mandatory	Path to a classpath resource or file on your filesystem
:container-path	String, mandatory	Path, to which the file should be copied
:type	Keyword, mandatory	:classpath-resource or :host-path

Result:

The container-config

Example:

(copy-file-to-container! container {:path           "test.sql"
                                    :container-path "/opt/test.sql"
                                    :type           :host-path})

---

execute-command!

Executes a command in the running container, and returns the result

Config parameters:

Key	Type	Description
First parameter:
container-config	Map, mandatory	Return value of the create function
Second parameter:
command	Vector with Strings, mandatory	A vector containing the command and its parameters

Result:

Key	Type	Description
:exit-code	int	Exit code of the executed command
:stdout	String	Content of stdout
:stdin	String	Content of stdin

Example:

(execute-command! container ["tail" "/opt/test.sql"])

create-network

Creates a network. The optional map accepts config values for enabling ipv6 and setting the driver

Config parameters:

Key	Type	Description
:ipv6	boolean	Should the network enable IPv6?
:driver	String	The network driver used by Docker, e.g. bridge or host

Result:

Key	Type	Description
:network	org.testcontainers.containers.Network	The instance of the network
:name	String	The name of the network
:ipv6	boolean	Does the network enable IPv6?
:driver	String	The network driver used

Example:

;;Create with config
(create-network {:ipv6   false
                 :driver "overlay"})

;;Create with default config
(create-network)

perform-cleanup!

Stops and removes all containers which were created in the JVM, including the REPL session you are in. This is helpful, if you are exploring functionality with containers in the REPL, and create lots of instances on the fly without stopping them. Testcontainers will remove all containers upon JVM shutdown, but the REPL keeps the JVM alive for a long time.

Config parameters:

None

Result:

None

Example:

(perform-cleanup!)

dump-logs

Call on a started container. Provided logging was enabled for a container, returns the given log presentation, e.g. as a string

Key	Type	Description
container-config	Map, mandatory	The configuration describing the container for which the log should be retrieved

License

Distributed under the Eclipse Public License either version 1.0 or (at your option) any later version.