API

This uses the HTTP REST API from the container engines to run. See the API docs for more details:

• Docker docs
• Podman docs

How does it work?

• The Swagger 2.0 specs are downloaded and parsed into relevant edn files.
• They are categorized by engine type and stored into the resources with version numbers.
• The code doing this can be found here.
• The library is then published with only the parsed and optimized edn to be as lean as possible at runtime have optimal performance.
• The main code then loads the corresponding edn file by version and performs the necessary calls to the engine.

This library aims to be a as thin layer as possible between you and the container engine. This consists of following public functions:

categories

Lists the categories of operations supported.

(c/categories :docker "v1.41") ; for docker

(c/categories :podman "v3.2.3") ; for podman

#_=> (:system
      :exec
      :images
      :secrets
      :events
      :_ping
      :containers
      :auth
      :tasks
      :volumes
      :networks
      :build
      :nodes
      :commit
      :plugins
      :info
      :swarm
      :distribution
      :version
      :services
      :configs
      :session)

Some engines like podman support multiple APIs, for example it supports both podman and docker APIs. Hence the categories would be namespaced to show which belong to what engine. eg. :containers for docker and :libpod/containers for podman APIs.

client

Connect to the UNIX socket and create a client scoped to the operations of a given category.

(def images (c/client {:engine   :podman
                       :category :libpod/images
                       :conn     {:uri "unix:///var/run/podman.sock"}
                       :version  "v3.2.3"}))

Using a timeout for the connections. Some actions can take quite a long time so set the timeout accordingly. When you don't provide timeouts then there will be no timeout on the client side.

(def ping (c/client {:engine   :docker
                     :category :_ping
                     :version  "v1.41"
                     :conn     {:uri             "unix:///var/run/docker.sock"
                                :connect-timeout 10
                                :read-timeout    30000
                                :write-timeout   30000
                                :call-timeout    30000}}}))

Alternatively if connecting to a remote engine over TCP supply the :uri as http://your.engine.host:2376. NOTE: unix://, http://, tcp:// and https:// are the currently supported protocols.

ops

Lists the supported ops by a client.

(c/ops images)

#_=> (:ImageDeleteLibpod
      :ImagePushLibpod
      :ImageExportLibpod
      :ImageHistoryLibpod
      :ImageDeleteAllLibpod
      :ImageInspectLibpod
      :ImageGetLibpod
      :ImageUntagLibpod
      :ImageTagLibpod
      :ImageChangesLibpod
      :ImageListLibpod
      :ImageLoadLibpod
      :ImageTreeLibpod
      :ImagePruneLibpod
      :ImageSearchLibpod
      :ImageImportLibpod
      :ImageExistsLibpod
      :ImagePullLibpod)

doc

Returns the summary and the doc URL of an operation in a client.

(c/doc images :ImageList)

#_=> {:summary
      "List Images\nReturns a list of images on the server. Note that it uses a different, smaller representation of an image than inspecting a single image.",
      :doc-url "https://docs.docker.com/engine/api/v1.41/#operation/ImageList"}

invoke

Invokes an operation via the client and a given operation map and returns the result data.

; Pulls the busybox:musl image from Docker hub
(c/invoke images {:op     :ImageCreate
                  :params {:fromImage "busybox:musl"}})

; Creates a container named conny from it
(c/invoke containers {:op     :ContainerCreate
                      :params {:name "conny"}
                      :data   {:Image "busybox:musl"
                               :Cmd   "ls"}})

The operation map is of the following structure:

{:op     :NameOfOp
 :params {:param-1 "value1"
          :param-2 true}
 :data   {map or stream or raw data to be passed. Corresponds to the Request Body in the docs}}

Takes an optional key as. Defaults to :data. Returns an InputStream if passed as :stream, the raw underlying network socket if passed as :socket. :stream is useful for streaming responses like logs, events etc, which run till the container is up. :socket is useful for events when bidirectional streams are returned by docker in operations like :ContainerAttach.

{:op     :NameOfOp
 :params {:param-1 "value1"
          :param-2 true}
 :as     :stream}

Note: :socket is unsupported on the babashka runtime for now.

Takes another optional key :throw-exceptions. Defaults to false. If set to true will throw an exception for exceptional status codes from the Docker API i.e. status >= 400. Throws an java.lang.RuntimeException with the message.

{:op               :NameOfOp
 :throw-exceptions true}

In general if any param is documented to take a file or a binary string, pass an input-stream to it. This would not only make it more efficient but should keep the encoding correct. For example: https://docs.docker.com/engine/api/v1.41/#operation/ImageLoad