2021/11/20 Introduce Clojerl for Alchemist

Introduce ClojerlClojerl.icon for AlchemistElixir.icon

2021/11/20 @ 2021/11/20 tokyo.ex Reboot #tokyoex

ne-sachirou.icon

.｡oO(さっちゃんですよヾ(〃l _ l)ﾉﾞ☆)

株式會社はてな株式會社はてな.iconで MackerelMackerel.icon を作ってゐます

ClojerlClojerl.icon =

ClojureClojure.icon

on ErlangErlang.icon VM

I 💕 ErlangErlang.icon VM

Free from crush.

supervisor and gen_server is a natural model of heterogeneous parallel processes.

I 💕 ClojureClojure.icon

It's Lisp.

Program is data.

Data is immutable.

Data is explicit. It's a map or a sequence.

Writing tests is very easy.

Libraries (both standard & 3rd. party) are basically stable, because data is stable.

Funny features🌟 including core.async & clojure.spec.

I 💕 ClojureClojure.icon

Runs on stable runtimes.

JVM : ClojureClojure.icon on JVM

Clojure - Java Interop

code:interop.clj

(.exampleMethod (ExampleJavaClass. arg1 arg2) arg3 arg4)

.NET : Clojure.NET

ECMAScript : ClojureScriptClojureScript.icon

ClojureScript - Quick Start

code:interop.cljs

(.querySelectorAll js/document ".class")

Erlang VMErlang.icon : ClojerlClojerl.icon (unofficial)

code:interop.clje

(exam.ple/erl-fun arg1 arg2)

Easy to integrate with other language's environments.

Python : libpython-clj on JVM

clj-python/libpython-clj: Python bindings for Clojure

code:libpython.clj

(require-python 'numpy :as np)

(np/array 1 2] [3 4)

ElixirElixir.icon$ \capClojerlClojerl.icon

ErlangErlang.icon VM

ErlangErlang.icon interoperability

Elixir.icon:module_name.f()

Clojerl.icon(module_name/f)

Functional programming.

threading (pipe operator)

Elixir.iconv |> f |> g

Clojerl.icon(-> v f g)

Data is basically immutable. Variable is reasignable.

$ diff ElixirElixir.icon ClojerlClojerl.icon

code:diff

- Phoenix

- Nerves

+ Lisp

+ Data oriented

+ Clojure ecosystem

data oriented programming

Example : Create a Web server

ne-sachirou/clojerl-example-20211120: Introduce Clojerl for Alchemist

Create a new project

$ rebar3 new clojerl_app example

Add Cowboy

Nine Nines: Cowboy User Guide

code:diff

diff --git a/rebar.config b/rebar.config

index a9410fa..95f5937 100644

--- a/rebar.config

+++ b/rebar.config

@@ -1,4 +1,5 @@

{erl_opts, debug_info}.

-{deps, {clojerl, "0.9.0"}}.

+{deps, [{clojerl, "0.9.0"},

+ {cowboy, "2.9.0"}]}.

{plugins, {rebar3_clojerl, "0.8.8"}}.

diff --git a/src/example.app.src b/src/example.app.src

index 1b8fb83..ddfc3cc 100644

--- a/src/example.app.src

+++ b/src/example.app.src

@@ -6,6 +6,7 @@

, [ stdlib

, kernel

, clojerl

+ , cowboy

]

}

, {mod, {'example.app', []}}

Create a webserver module to start Cowboy

code:clojure

;; src/example/webserver.clje

(ns example.webserver

(:require

cowboy

erlang

erlang.core

example.index-handler))

(erlang.core/behaviours gen_server)

(defn child-spec

[]

{:id :example.webserver

:start :example.webserver :start-link #erl()

:restart :permanent

:shutdown :brutal_kill

:type :worker

:modules '(:example.webserver)})

(defn start-link

[]

(gen_server/start_link #erl:local :example.webserver,

:example.webserver

nil

#erl()))

(defn init

(let [dispatch (cowboy_router/compile (clj->erl '(:example.index-handler nil)))]

(let* [#erl:ok listener-pid (cowboy/start_clear :example.listener

#erl(#erl:port 8080)

#erl{:env #erl{:dispatch dispatch}})]

(erlang/link listener-pid)))

#erl:ok nil)

(defn handle_call

_ state

#erl:noreply state)

(defn handle_cast

state

#erl:noreply state)

code:clojure

;; src/example/index_handler.clje

(ns example.index-handler)

(defn init

req state

(let [req (cowboy_req/reply 200

#erl{"content-type" "text/plain"}

"Hello Clojerl"

req)]

#erl:ok req state))

Supervise it.

code:diff

diff --git a/src/example/sup.clje b/src/example/sup.clje

index 4c5f198..1e74a1f 100644

--- a/src/example/sup.clje

+++ b/src/example/sup.clje

@@ -1,10 +1,16 @@

-(ns example.sup)

+(ns example.sup

+ (:require

+ erlang.core

+ example.webserver

+ supervisor))

(def sup-flags #erl{:strategy :one_for_one

:intensity 1

:period 5})

-(def child-specs #erl())

+(def child-specs #erl((clj->erl (example.webserver/child-spec))))

(defn start-link []

(supervisor/start_link #erl:local :example.sup

Start the application

$ rebar3 clojerl repl --apps example

Check it.

$ curl http://localhost:8080

Hello Clojerl

It's just a normal Cowboy application in ClojureClojure.icon world.

Monitoring the application by OpenTelemetryOpenTelemetry.icon

Add opentelemetryOpenTelemetry.icon

Erlang/Elixir | OpenTelemetry

code:diff

diff --git a/config/sys.config b/config/sys.config

new file mode 100644

index 0000000..18c775e

--- /dev/null

+++ b/config/sys.config

@@ -0,0 +1,7 @@

+ {opentelemetry,

+ [{processors, [{otel_batch_processor,

+ #{exporter => {otel_exporter_stdout, []}}

+ }]

+ }]}

+].

diff --git a/rebar.config b/rebar.config

index 95f5937..922cfa0 100644

--- a/rebar.config

+++ b/rebar.config

@@ -1,5 +1,9 @@

{erl_opts, debug_info}.

{deps, [{clojerl, "0.9.0"},

- {cowboy, "2.9.0"}]}.

+ {cowboy, "2.9.0"},

+ {opentelemetry_api, "~> 1.0.0-rc.3"},

+ {opentelemetry, "~> 1.0.0-rc.3"}]}.

{plugins, {rebar3_clojerl, "0.8.8"}}.

+{shell, {config, "config/sys.config"}}.

diff --git a/src/example.app.src b/src/example.app.src

index ac6c9a9..2441fb4 100644

--- a/src/example.app.src

+++ b/src/example.app.src

@@ -5,6 +5,8 @@

, { applications

, [ stdlib

, kernel

+ , opentelemetry_api

+ , opentelemetry

, clojerl

, cowboy

]

Trace requests

code:diff

diff --git a/src/example/index_handler.clje b/src/example/index_handler.clje

index 2b84853..ee49789 100644

--- a/src/example/index_handler.clje

+++ b/src/example/index_handler.clje

@@ -1,10 +1,45 @@

-(ns example.index-handler)

+(ns example.index-handler

+ (:require

+ erlang

+ maps

+ opentelemetry))

+(defn now-microsecs

+ []

+ (let* [#erlmega-secs secs microsecs (erlang/now)]

+ (->> mega-secs

+ (* 1000)

+ (+ (->> secs

+ (* 1000000)))

+ (+ microsecs))))

+(defn with-response-time-span

+ callback attributes

+ (let [module (-> *ns* ns-name name)

+ tracer (-> module erlang/binary_to_existing_atom opentelemetry/get_application_tracer)]

+ (otel_tracer/with_span tracer

+ module

+ #erl{}

+ (fn _span-ctx

+ (let* [now-1 (now-microsecs)

+ resp (callback)

+ now-2 (now-microsecs)

+ attributes (-> (merge {"response-time" (- now-2 now-1)} attributes)

+ clj->erl

+ maps/to_list)]

+ (otel_span/set_attributes (otel_tracer/current_span_ctx) attributes)

+ resp)))))

(defn init

req state

- (let [req (cowboy_req/reply 200

- #erl{"content-type" "text/plain"}

- "Hello Clojerl"

- req)]

- #erl:ok req state))

+ (with-response-time-span

+ (fn []

+ (let [req (cowboy_req/reply 200

+ #erl{"content-type" "text/plain"}

+ "Hello Clojerl"

+ req)]

+ #erl:ok req state))

+ {"path" "/"}))

Start the application

$ rebar3 clojerl compile && rebar3 shell --apps example

Check it.

$ ab -n 100 -c 10 'http://127.0.0.1:8080/'

code:erlang

{span,206190385536417520207509724574528174945,12710625632486370212,[],

undefined,<<"clojure.core">>,internal,-576460738214198000,

-576460738204198000,

{<<"path">>,<<"/">>},{<<"response-time">>,16},

[],[],undefined,1,false,

{instrumentation_library,<<"clojerl">>,<<"0.9.0">>}}