Cannot connect remote REPL properly
Here are the steps I do:
Start local repl instance:
lein repl
Connect to local by remote repl instance(I do it through Intellij IDEA)
After this, every output in code goes only in local repl, in remote one there are nothing
What I need: to see all outputs in both repl instances
I have found partial solution, this code rebinds output of one repl to another. Just run it in remote one, and all output will go to it
(defn rebind-output []
(prn "Rebinding output...")
(System/setOut (PrintStream. (WriterOutputStream. *out*) true))
(System/setErr (PrintStream. (WriterOutputStream. *err*) true))
(alter-var-root #'*out* (fn [_] *out*))
(alter-var-root #'*err* (fn [_] *err*)))
out - is intstance of PrintWriter
However what I need is: see BOTH repls outputing the same, how to do it?
I can't seem to think that you are confused about how to connect to an existing REPL (the one you launch from the command line with lein repl). Did you check the section Remote REPLs in the Cursive manual?
Generally, you want only one of these:
Launch the REPL from Intellij itself on a project that is already managed with Leiningen (eg. it already has a project.clj file), or
Connect to an already running REPL, one that is running on the same host, or in a different machine.
If you are starting lein repl yourself in a console, you'll see that it prints some messages on startup:
$ lein repl
nREPL server started on port 39919 on host 127.0.0.1 - nrepl://127.0.0.1:39919
In this example, the server started listening on my own host (127.0.0.1 or localhost) on port 39919 (this port will change each time you launch the REPL with lein repl). You'll need to enter these values in Intellij to be able to connect to this REPL.
Related
I am using boot, and I am happy with it so far.
I still have to run two tasks currently, in two different consoles :
boot dev and boot autotest.
Therefore I would like to know it it is feasible/advised to make all boot tasks within the same JVM.
I tried to compose the tasks like so :
(deftask autotest []
(comp
(watch)
(run-tests)))
(deftask dev
"Start the dev env..."
[t run-tests bool "Run the tests continuously"]
(comp
....
(if run-tests (autotest) identity)))
But now when running boot dev -t I get an exception from one of the libraries that I am using, which could mean that I have to isolate it.
Are boot tasks intended to be used like that, and can boot pods solve my problem ?
Answering my own question:
I no longer have this exception
this is one of the strength of boot to use one single JVM (as opposed to leiningen)
I have a Ring app that through deploys to production as an uberwar thing; myservice.war. In production the WAR file gets tossed into Jetty where it runs in a context that follows its name
$ curl -i -X GET http://myservice.qa1.example.com:8080/myservice/healthz
HTTP/1.1 200 OK
...
When I run locally through lein ring, I need it to run in the same context; myservice.
$lein ring server-headless
2015-10-14 14:04:03,457 level=INFO [main] Server:271 - jetty-7.6.13.v20130916
2015-10-14 14:04:03,482 level=INFO [main] AbstractConnector:338 - Started SelectChannelConnector#0.0.0.0:10313
Started server on port 10313
But the same curl goes all 404 on me locally.
$ curl -i -X GET http://localhost:10313/myservice/healthz
HTTP/1.1 404 Not Found
...
The lein ring thing deployed it onto the root context.
$ curl -i -X GET http://localhost:10313/healthz
HTTP/1.1 200 OK
...
Whats up with that? How do I direct lein ring to deploy into a context name of my choosing? I need curl -i -X GET http://localhost:10313/myservice/healthz to work from lein ring
One way to work around this issue is to create the second (standalone) set of routes for your app. You also create the second handler for the standalone case. Then you can use Leiningen profiles to specify different handlers for the standalone case and the uberwar case. The default profile is used when running the app standalone. The :uberjar profile is used when the uberwar is created. As a result, your standalone handler going to be used with lein ring server-headless and your regular handler is going to be used when the war is deployed into a container.
Not much additional code needed to create the second set of routes. You can just wrap the existing routes in a context of your choosing. Suppose the following are your routes and ring handler:
(defroutes app-routes
(GET "/healthz" [] "Hello World")
(route/not-found "Not Found"))
(def app
(wrap-defaults app-routes site-defaults))
Additional routes and handler for the standalone case would look like this:
(defroutes standalone-routes
(context "/myservice" req app-routes)
(route/not-found "Not Found"))
(def standalone-app
(wrap-defaults standalone-routes site-defaults))
Now, onto lein-ring configuration in project.clj. We want the default ring handler to point to standalone-app. The ring handler for the uberwar should point to app. The :ring entry in the project map in project.clj should look like this (adjust for your actual namespace):
:ring {:handler myservice.handler/standalone-app}
Also, merge the following into your :profiles map in project.clj:
:uberjar {:ring {:handler myservice.handler/app}}
Please be sure to use the latest version of the lein-ring plugin. Version 0.9.7 worked for me. Earlier versions, like 0.8.3, did not work because they did not use the :uberjar profile when running the uberwar task.
If you do all this, and assuming your war file is called myservice.war, the context part of the URI is going to be the same whether your app is started with lein ring server-headless or if the war file is deployed in Jetty.
$ curl http://localhost:[port]/myservice/healthz
I have a Clojure app that I can use both from the command-line, and as a Compojure app.
I did that by putting a ring handler and a main function (clojure.tools.cli) in my leiningen project.clj.
{...
:main my-app.core
:ring {:handler my-app.handler/handler }}
The handler is defined (defroutes handler ...).
Now if I want to run the CLI app, I can run lein uberjar and then java -jar arguments.
And I can also run the Compojure app via lein ring server PORT.
Now, how do I deploy the thing as a Compojure app (and not a CLI app) in a production server ? (Bonus points for explaining how lein ring server works.)
Note : I already use nginx if that can help, and I'm flexible on the container to be used.
Here's kind of the default template I use for new projects. It allows you to do dependency injection into ring apps and run the app from the command line as an uberjar. You can read more here: http://www.sparxeng.com/blog/software/improved-clojure-workflow
; handler.clj
(defn wrap-inject-deps
"Ring middleware that injects the dependencies into each ring request map"
[handler deps]
(fn [req]
(handler (assoc req :deps deps))))
(defn create-handler
"Similar to the default ring 'handler', but with a parameter to let you inject dependencies"
[deps]
(-> (routes
api-routes
web-routes
(route/resources "/"))
(kwp/wrap-keyword-params)
(params/wrap-params)
(json/wrap-json-params)
(json/wrap-json-response)
(wrap-inject-deps deps))) ; this injects dependencies
(defn start-jetty
"Launch the Jetty instance"
[deps]
(let [port (Integer. (or (-> system :env :port) 5000))
handler (create-handler deps)]
(jetty/run-jetty handler {:port port :join? false})))
; system.clj
(defn get-env
"Initialize configuration vars"
[]
{:aws-access-key-id (System/getenv "AWS_ACCESS_KEY_ID")
:aws-secret-access-key (System/getenv "AWS_SECRET_ACCESS_KEY")
:mongo-url (System/getenv "MONGO_URL"))
(defn start
"Launch dependencies such as DB connection and Jetty. Return these as a map, for use in REPL"
[& [env]]
(let [env (or env (get-env))
deps {:env env
:monger (db/init env)}
jetty (handler/start-jetty deps)]
(assoc deps :jetty jetty)))
; program.clj
(defn -main [& [port]]
"App entrypoint"
(let [env (system/get-env) ; "env" is just a map of config variables, that can be hard-coded, read from file, or whatever you want.
env (if port (assoc env :port port) env)]
(system/start env)))
You can then use leiningen profiles if you need to create multiple apps with different entrypoints from your codebase.
lein ring server fires up jetty to serve the web application you've built. It does this by starting the server with the options you specify in :ring. If you specify LEIN_NO_DEV in your environment, the server will run in production mode. Whether jetty is the right fit for your productions needs or not, is up to you to decide.
If you would like to run your web application on a different server, there are multiple options. One of them is running on Tomcat. Take another look at the documentation for lein ring, in particular the section on war files. Basically, you would call lein war or lein uberwar to generate a war file. You can then e.g. drop the war file into the webapps directory of Tomcat.
Another option would be using immutant, which has substantial documentation on installation and running applications.
Update: this question has changed since the original set of commenters left responses. Apologies for any confusion.
This is my code repository https://github.com/Integralist/spurious-clojure-example you can use it as an example for what I'm working with.
Note that the above repo relies on a library I've not yet published to Clojars (as I'm still testing it - hence this question opened). You can see the source code of the library here: https://github.com/Integralist/spurious-clojure-aws-sdk-helper
I have a "hello world" Clojure web app written with Compojure that I have working fine when run using lein ring server and lein run (as I have a -main function now created). It also runs to a certain extent when compiled down into a jar and I run java -jar app.jar.
My problem now is that if I try to run the default java -jar app.jar from within a Docker container I get the following error telling me...
spurious-clojure-example is starting
2015-02-14 00:58:03.812:INFO:oejs.Server:jetty-7.x.y-SNAPSHOT
2015-02-14 00:58:03.854:INFO:oejs.AbstractConnector:Started SelectChannelConnector#0.0.0.0:8080
Started server on port 8080
Exception in thread "main" java.awt.HeadlessException:
My code is currently using a -main function like so...
(ns spurious-clojure-example.repl
(:use spurious-clojure-example.handler
ring.server.standalone
[ring.middleware file-info file])
(:gen-class))
(defonce server (atom nil))
(defn get-handler []
(-> #'app
(wrap-file "resources")
(wrap-file-info)))
(defn start-server
"used for starting the server in development mode from REPL"
[& [port]]
(let [port (if port (Integer/parseInt port) 8080)]
(reset! server
(serve (get-handler)
{:port port
:init init
:auto-reload? true
:destroy destroy
:join true}))
(println (str "You can view the site at http://localhost:" port))))
(defn stop-server []
(.stop #server)
(reset! server nil))
(defn -main []
(start-server))
...but how do I get the server to start headless? I can't quite follow the Compojure boilerplate code to decipher where or how it knows when to run headlessly or via browser?
I know that on the command line you can do lein ring server-headless so what's the programmatic equivalent of that?
Because ring-server is primarily meant for development, it tries to open a browser when the server starts. This fails with a java.awt.HeadlessException on platforms without a GUI. You'll want to set the :open-browser? option to false to prevent this.
From the offical Docker docs on EXPOSE
The EXPOSE instructions informs Docker that the container will listen
on the specified network ports at runtime. Docker uses this
information to interconnect containers using links (see the Docker
User Guide) and to determine which ports to expose to the host when
using the -P flag. Note: EXPOSE doesn't define which ports can be
exposed to the host or make ports accessible from the host by default.
To expose ports to the host, at runtime, use the -p flag or the -P flag.
So if you're setting the ring server port manually in your project.clj, ensure that you're using the same port also in your Dockerfile and then provide a mapping via -p or -P when starting docker.
I can't say for sure but I believe that your headless error message doesn't contribute to your problem.
My clojure noir app works 100% fine locally and connects to RedisToGo no problem.
The problem is when I deploy to Heroku (git push heroku master), I get a timeout error:
Error R10 (Boot timeout) -> Web process failed to bind to $PORT within 60 seconds of launch
Full log is here: https://gist.github.com/1842439
When I remove this redis connection code, it deploys fine:
(:use [aleph.redis :only (redis-client)])
(def r (redis-client {:host redis-url :password redis-pass :port redis-port}))
The weird thing is that when I run "heroku run lein run repl" and paste in the aleph code above, it connects to redis fine and I can read/write data.
So it something about how heroku boots up the app thats breaking the connection to RedisToGo and timing it out.
Doing something side-effecty at the top level is very suspect - that code is executed when compiling as well as when executing, so probably the automatic uberjar Heroku does is failing because redis isn't available at compile time, or something like that.
Instead, initialize your redis client after -main has been called, which will ensure you are in a production environment. You can accomplish this in a number of ways, for example by initially defining it to nil and then performing an alter-var-root in -main. My preferred solution would probably be something like:
(def r (delay (redis-client ...)))
(defn get-stuff []
(let [client #r] ...))
(defn -main [& args]
(get-stuff)
...)
Now the code to connect isn't performed until someone derefs the client, which they should never do until the app is up and running.