Dockerfile example

Haskell/DockerfileExample.hs

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+#!/usr/bin/env nix-shell
+#! nix-shell -I nixpkgs=https://github.com/NixOS/nixpkgs/archive/19.09.tar.gz --pure -i runhaskell -p "pkgs.haskell.packages.ghc881.ghcWithPackages (ps: with ps; [ dockerfile containers ])"
+{-# OPTIONS_GHC -Wall -Werror #-}
+{-# LANGUAGE PackageImports #-}
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE BangPatterns #-}
+{-# LANGUAGE DeriveDataTypeable #-}
+{-# LANGUAGE DeriveGeneric #-}
+
+import "base"       Data.Foldable (foldl')
+import "base"       GHC.Generics (Generic)
+import "base"       Data.Typeable (Typeable)
+import "base"       Data.Data (Data)
+import "containers" Data.Map.Strict (Map, empty, assocs)
+import "dockerfile" Data.Docker
+import "directory"  System.Directory (getCurrentDirectory)
+
+data OS = Ubuntu
+        | RedHat
+        | CentOS
+        deriving (Show, Read, Eq, Ord, Enum, Bounded, Data, Typeable, Generic)
+
+data User = Root
+          | User { _user_name :: !String }
+          deriving (Show, Read, Eq, Ord, Data, Typeable, Generic)
+
+type Entrypoint = (String, [String])
+
+data ContainerEnv = ContainerEnv 
+          { _containerEnv_OS :: !OS 
+          , _containerEnv_users :: ![User]
+          , _containerEnv_image :: !String
+          , _containerEnv_installations :: ![(String, [String])]
+          , _containerEnv_env :: !(Map String String)
+          , _containerEnv_runCmds :: ![String]
+          , _containerEnv_entrypoint :: !(Maybe Entrypoint)
+          , _containerEnv_command :: !(Maybe [String])
+          } deriving (Show, Read, Eq, Ord, Data, Typeable, Generic)   
+
+aptInstalls :: (String, [String])
+aptInstalls = ("apt-get install -yq", ["python3", "python3-pip", "wget", "tar"])
+
+pipInstalls :: (String, [String])
+pipInstalls = ("pip3 install --user", ["jupyter"])
+
+runCmds :: [String]
+runCmds = ["wget http://apache.mirrors.hoobly.com/drill/drill-1.16.0/apache-drill-1.16.0.tar.gz", "tar -xzvf apache-drill-1.16.0.tar.gz"]
+
+jupyter :: Entrypoint
+jupyter = ("jupyter", ["notebook", "--ip-0.0.0.0", "--no-browser"])
+
+example :: ContainerEnv
+example = ContainerEnv Ubuntu 
+                       [User "atidot"] 
+                       "ubuntu" 
+                       [aptInstalls, pipInstalls]
+                       empty
+                       runCmds
+                       (Just jupyter)
+                       Nothing
+
+toDocker :: ContainerEnv -> Docker ()
+toDocker (ContainerEnv os users img pkgs environment toRun entrypoint' command) = do
+    from img
+    foreach (makeUser os) users
+    foreach (uncurry installPkgs) pkgs
+    foreach (uncurry env) $ assocs environment
+    foreach run toRun
+    doIfJust (uncurry entrypoint) entrypoint'
+    doIfJust cmd command
+        where doIfJust _ Nothing = return ()
+              doIfJust f (Just x) = f x
+
+foreach :: (a -> Docker ()) 
+        -> [a] 
+        -> Docker ()
+foreach f xs = foldl' (>>) (return ()) (map f xs)
+
+-- The last character of the string passed to `run` would be '\n' without the 
+-- call to `take`. Removing the '\n' standardizes the whitespace.
+installPkgs :: String
+            -> [String] 
+            -> Docker ()
+installPkgs installer pkgs = run (take (length installation - 1) installation)
+    where installation = foldl' (++) (installer ++ endl1) (map instLine pkgs)
+          instLine pkg = "    " ++ pkg ++ endl pkg
+          endl pkg     = replicate (maxLength - paddedLength pkg) ' ' ++ " \\\n"
+          paddedLine1  = "RUN " ++ installer ++ " \\"
+          endl1        = replicate (maxLength - length paddedLine1) ' ' ++ " \\\n"
+          maxLength    = maximum $ map length (paddedLine1 : map pad pkgs)
+          paddedLength = length . pad
+          pad pkg      = "    " ++ pkg ++ " \\"
+
+addUserProgram :: OS -> String
+addUserProgram Ubuntu = "adduser"
+addUserProgram CentOS = "adduser"
+addUserProgram RedHat = "useradd"
+
+makeUser :: OS 
+         -> User 
+         -> Docker ()
+makeUser _  Root         = return ()
+makeUser os (User uname) = do
+    run (addUserProgram os ++ " " ++ uname)
+    user uname
+    workdir ("/home/" ++ uname)
+    env "PATH" "/home/atidot/.local/bin:${PATH}"
+
+main :: IO ()
+main = do
+    pwd <- getCurrentDirectory
+    let dockerPath = pwd ++ "/DockerfileExample"
+    dockerfileWrite dockerPath $ toDocker example