Clojurians Log v2

hi there! how to start all states in current namespace only?

i have 10 or more states and want to avoid enumerate them all

(mount/start #'foo #'bar ....)

@mike1452: hey Mike, mount does not have API to scope the states by a namespace, but you can easily do it by:

dev=> (require '[clojure.string :as s])

dev=> (defn start-ns [ns]
       (->> (mount/find-all-states)
            (filter #(s/starts-with? % ns))
            mount/start))

dev=> (start-ns "#'neo.conf")
INFO  neo.conf - loading config from dev/resources/config.edn
{:started ["#'neo.conf/config"]}

I just opened a mount/find-all-states function in 0.1.11-SNAPSHOT. (it used to be private)

@tolitius Thanx! 🙂

sure, let me know if it works for you

@tolitius is it correct way to check?

dev=> ((mount/running-states) "#'app.db/conn")
nil

dev=> (mount/start)
{:started ["#'app.conf/config" "#'app.db/conn" "#'app.www/nyse-app" "#'app.example/nrepl"]}

dev=> ((mount/running-states) "#'app.db/conn")
"#'app.db/conn"

@tolitius If i have states: config, conn and obj - all of them in current namespace. And I want to not start conn if config not started. And not start obj if conn is not started. Under "not started" i mean any case that is not success in terms of state. For example, if I've got Exception during conn - it is "not success" cause resource is unavailable. What value should I put to conn state if "not success"? (mount.core.NotStartedState. "conn") ? Have you some semantics for values? So and I want to check in depended states if state is not started then I log error. "bit cleaner" variant is not handy for such case.

or it is error state and I should introduce some values for "error state" and check for "not started" and "error state"?

it might have to do with: https://github.com/tolitius/mount/issues/50

I am still digesting your use case.. give me a couple of seconds

let's say you have 3 states: config, conn and obj the problem you're trying to solve is: * not to start conn on case you could not start conf * not to start obj on case you could not start conn ?

yes

not start conn if conf not-started or in error state

in case we are talking about just (mount/start ...)

not start conn if conf in error state

not start conn if conf not-started state

so, are you talking about starting parts of your app in steps?

"since mount will stop in case there is an error starting" - that is what I want, but didn't catch.

I put intentionally 1/0

and config and all depended states will be in started state but iti is not true

mount didn't catch that i've got and exeception

boot.user=> (defstate a :start (/ 1 0))
#'boot.user/a
boot.user=> (defstate b :start (println "starting a with b:" b))
#'boot.user/b
boot.user=> (mount/start)

   java.lang.RuntimeException: could not start [#'boot.user/a] due to
java.lang.ArithmeticException: Divide by zero
boot.user=>

boot.user=> (mount/running-states)
#{}

hmmm, I will check right now ones more

boot.user=> (defstate ^:dynamic config :start (do (/ 1 0) (println "config is started")))
#'boot.user/config
boot.user=> (defstate db :start (println "starting db with config" config))
#'boot.user/db
boot.user=> (mount/start)

   java.lang.RuntimeException: could not start [#'boot.user/config] due to
java.lang.ArithmeticException: Divide by zero
boot.user=> (mount/running-states)
#{}

no such var mount/running-states

is it in 0.1.11 ?

ah.. it could be yes

might need to release it soon, since there are several small fixes there as well

0.1.11-SNAPSHOT

ok, cool. mount will not start if got an unhandled Exception

but, what if I have try-catch block inside and process Exception my self. What value should i return in order to tell mount this is not correct state?

I mean

in case you want to signal a problem don't do try/catch, or if you need to do it re throw the exception

@tolitius got it! thanx!

sure, good luck 🙂