Clojure in the Cloud Everett Toews Developer JavaOne Sept. 29, 12:30 pm

Intro Developer

PMC and Committer on Apache jclouds

Intro Advocate

Operations

Co-author of The OpenStack Ops Guide docs.openstack.org/ops

Clojure

List

(2 3)

Clojure Vector

[2 3]

Clojure Map

{:key1 "value1" :key2 "value2"} :key2 "value2"}

Clojure Parens

(fn arg1 arg2) (sf arg1 arg2)

Clojure Prefix

(+ 2 3) ; 5

Clojure Functional

(defn add-7 [x] [x] (+ x 7)) (+ x 7))

(add-7 3) ; 10

(map add-7 [2 3]) ; (9 10)

Clojure Types

(add-7 "3") ; ClassCastException java.lang.String cannot be cast to java.lang.Number

Clojure Destructuring

1 (defn print-args 2 [f & rest] 3 (println f) 4 (println 5 (apply sorted-map rest)))

(print-args "first" :k3 "v3" :k1 "v1" :k3 "v3" :k1 "v1" :k2 "v2") :k2 "v2") ; first ; {:k1 v1, :k2 v2, :k3 v3}

Clojure Lambda

(map (fn [x] (+ x 7)) (fn [x] (+ x 7)) [2 3]) [2 3]) ; (9 10)

Clojure Macro

(defmacro when [test & body] [test & body] (list 'if test (list 'if test (cons 'do body))) (cons 'do body)))

(when true (+ 2 3)) ; 5

Clojure lein

lein new app github-comment-clj lein clean lein install lein test lein run lein repl

Clojure REPL

PrintEvalRead Loop

Cloud

SaaS

IaaS

Resources Accessible Via HTTP API

HTTP APIs

Documentation

Logging

Auth

Endpoint

Environment

Connect!

Request

Response

Headers

Body

JSON

Clojure in the Cloud

Conjecture in the Cloud ClojectureConjecture

Clojure in the Cloud Clojure > Java

Clojure in the Cloud Domain Modeling vsMaps

Example ExampleSurprise!

"""" {"key": "value"} Map Map

"" {"key": {BLAH}}ParseException

Example Example Changing Objects

"""" {"obj": "BLAH"} "" {"obj": {BLAH}} "" {"obj": [BLAH]}

Clojure in the Cloud Example Huge Objects

Clojure in the Cloud Maps

WARNING Demos Ahead

Clojure in the Cloud Compile/Run/printlnvsREPL

Demo lein repl

Clojure in the Cloud pom.xml/mvn/Classvs lein try

Clojure in the Cloud Demo lein try

Clojure in the Cloud Works For Me vs I Feel Your Pain

Clojure in the Cloud Demo lein repl :connect

Use Case

GitHubTwitter Rackspace Jenkins Developer 1.PR 2. Webhook 4. Comment 3. Status 5. Save

Talkin’ HTTP

HTTP Library

clj-http

Talkin’ HTTP Java SDK

Hosebird Client (hbc)

Talkin’ HTTP Clojure Bindings for Java SDK

Clojure Bindings for Java SDK Apache jclouds

Talkin’ HTTP Clojure SDK

twitter-apitentacles

twitter-api

:dependencies

1 [org.clojure/clojure "1.4.0"] ;; Clojure 2 [org.clojure/data.json "0.2.1"] ;; JSON 3 [http.async.client "0.5.2"] ;; HTTP 4 [clj-oauth "1.4.0"]] ;; OAuth

twitter-api Macros

1 (defmacro def-twitter-restful-method 2 [verb resource-path & rest] 3 (let [json-path (str resource-path ".json") 4 dashed-name (...) 5 clean-name (...) 6 fn-name (symbol clean-name)] 7 `(def-twitter-method ~fn-name ~verb ~json-path :api ~*rest-api* :callbacks (get- default-callbacks :sync :single)

1 (defmacro def-twitter-method 2 [fn-name default-verb resource-path & rest] 3 (let [rest-map (apply sorted-map rest)] 4 `(defn ~fn-name 5 [& {:as args#}] 6 (let [...] 7 (http-request verb# uri# arg-map#))))

1 (def-twitter-restful-method :get "statuses/home_timeline") 2 (statuses-home-timeline :oauth-creds twitter ‑ creds :params {:count 3}) ; {:headers {:content-length "7558",...} ; :status {:code 200,...} ; :body ; [{:text "Untappd but for Pho",...}...]}

1 (def-twitter-restful-method :post "statuses/update") 2 (statuses-update :oauth-creds twitter ‑ creds :params {:status ”Hi!"}) ; {:headers {:content-length ”1904",...} ; :status {:code 200,...} ; :body ; [{:text "Hi!",...}...]}

twitter-api Documentation

Logging

tentacles

:dependencies

1 [org.clojure/clojure "1.5.1"] ;; Clojure 2 [org.clojure/data.codec "0.1.0"] ;; Base64 3 [clj-http "0.4.0"] ;; HTTP 4 [cheshire "4.0.0"] ;; JSON 5 [com.cemerick/url "0.0.6"] ;; URLs 6 [environ "0.4.0"] ;; Env

tentacles Functions

1 (defn api-call 2 [method end-point positional query] 3 (let [query (query-map query) 4 all-pages? (query "all_pages") 5 req (make-request...) 6 exec-request-one (fn...(request req)) 7 exec-request (fn...)] 8 (exec-request req)))

1 (issues/create-comment "everett-toews” "github-comment-clj" 6 "Hi!" github-creds) ; {:url " ; :id , ; :user {:id ,...} ; :body "Hi!"}

tentacles Documentation

Logging

jclouds

:dependencies

1 [org.clojure/clojure "1.3.0"] ;; Clojure 2 [org.clojure/tools.logging "0.2.3"] ;; Log 3 [org.clojure/core.incubator "0.1.0"];; Inc 4 [org.apache.jclouds.labs/ rackspace-cloudfiles-us 1.8.0"] ;; BlobStore rackspace-cloudfiles-us 1.8.0"] ;; BlobStore

jclouds JavaClasses/Methods

1 (defn create-container 2 [^BlobStore blobstore container-name & 3 {:keys [location public-read?]}] 4 (let [cco (CreateContainerOptions.) 5 cco (if public-read?...)] 6 (.createContainerInLocation blobstore location container-name cco)))

1 (defn put-blob 2 [^BlobStore blobstore container-name blob & 3 {:keys [multipart?]}] 4 (let [options (if multipart?...)] 5 (.putBlob blobstore container-name blob options)))

1 (def my-blob (blob "my-file.log" :payload "my-file-contents")) ; #'blobstore.core/blob 2 (create-container blobstore "my-container") ; true 3 (put-blob blobstore "my-container" my-blob) ; "60e46aeaed dd7ae99858f03"

jclouds Documentation

Logging

Clojure in the Cloud

Thank You Clojure Made Simple Intro to Apache jclouds Everett Toews Developer