At what point did you **create** the Atom in :a? Any mutable references which need to be shared among all usages of a component must be created in the **constructor**, not the `start` or `stop` methods.
-S On Wednesday, April 30, 2014 5:13:15 PM UTC-4, frye wrote: > > Hi all, > > I'm having a weird state problem with > Component<https://github.com/stuartsierra/component>. > Let's say I have a system component, like in fig.1. Starting / stopping and > loading state is fine. > However, let's say I have 2 other components (:updater , :reader) that use > component :a. This is the problem that occurs. > > 1. When *:updater*, modifies an atom in *:a*, that change appears in > path [*:core :a*], not path [*:updater :a*] or [*:a*]. > 2. Because of the abouve, when *:reader* goes to it's local path [ > *:reader :a*] to read that change, it doesn't see those modifications. > 3. Using this scheme, *:a* is duplicated 4 times, in the system map. > However, the modifications only appear in path [*:core :a*]. Thus > :reader is unable to access it (it's local [*:a*] is unchanged). > > > (def system-components [:a :updater :reader]) > > (defrecord Core [env] component/Lifecycle > (start [this] ...) > (stop [this] ...)) > > (defn component-core [env] > > (component/system-map > :a (component/using > (ca/component-a env) > {}) > :updater (component/using > (cs/component-updater env) > {:a :a}) > :reader(component/using > (cs/component-reader env) > {:a :a}) > :core (component/using > (map->Foobar {:env env}) > {:a :a > > :updater :updater > > :reader :reader }))) > > *fig.1 * > > > I was hoping to use Component to manage all internal application state. > But maybe it's not designed for this use case (state changes between > components). I imagine that immutability is preventing all those duplicates > from seeing the modifications. However, in this case I do need an update to > :a in one component, to be accessed by another component. > > Any suggestions on patterns here? I'm also looking at > component/update-system<https://github.com/stuartsierra/component/blob/master/src/com/stuartsierra/component.clj#L116>. > > But again, I don't have access to the core *system* var, from within my > components. > > > Any insights appreciated > > Tim Washington > Interruptsoftware.com <http://interruptsoftware.com> > > > -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
