Hello, I think you are coming to a point where you might want to consider Stuart Sierra's component library. https://github.com/stuartsierra/component
A dynamic var is kind of thread-bounded global state, which is to be avoided. There is a nice talk to go with it https://www.youtube.com/watch?v=13cmHf_kt-Q Kr, Jo Op vrijdag 31 juli 2015 02:44:31 UTC+2 schreef J. Pablo Fernández: > > Hello Clojurians, > > I found passing around the database connection to each function that uses > it very error prone when you are using transactions as passing the wrong > one could mean a query runs outside the transaction when in the source code > it is inside the with-db-transaction function. So I ended up defining the > db namespace like this: > > (ns db) > > (defonce ^:dynamic conn (atom nil)) > > (defn connect! > (reset conn (generate-new-connection))) > > (defn run-query > [query] (run-query query @conn) > [query conn] (run-the-query-in-connection query conn)) > > > This is pseudo-code of course, simplified to highlight the part that I'm > most unfamiliar with: > > (defonce ^:dynamic conn (atom nil)) > > The reason why it's an atom is so that connect! can *set* it and the > reason why it's a dynamic var is so I can do this: > > (jdbc/with-db-transaction > [db-connection-with-transaction @db/conn] > (binding [db/conn (atom db-connection-with-transaction)] > (db/run-query "SELECT *")))))) > > and the query will be implicitly run inside the transaction. Does it make > sense? Is this wrong? will it fail in unexpected ways? Is there a better > way? > > Thanks. > > > -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to [email protected] Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to [email protected] 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 [email protected]. For more options, visit https://groups.google.com/d/optout.
