create (execute-all-reports) function which will run through all of our active...

create (execute-all-reports) function which will run through all of our active EmailReports and execute the ones that are scheduled to run in the current hour.  also adds in an hourly task hook for running (execute-all-reports).

src/metabase/tasks/email_report.clj

 (ns metabase.tasks.email-report
   "Tasks related to running `EmailReports`."
   (:require [clojure.tools.logging :as log]
+            [clj-time.core :as time]
             [korma.core :refer :all]
             [metabase.db :refer :all]
             [metabase.driver :as driver]
             [metabase.email.messages :refer [send-email-report]]
-            (metabase.models [emailreport :refer [EmailReport execution-details-fields]]
+            (metabase.models [emailreport :refer [EmailReport execution-details-fields mode->id time-of-day->realhour]]
                              [emailreport-executions :refer [EmailReportExecutions]]
                              [emailreport-recipients :refer [EmailReportRecipients]]
                              [hydrate :refer :all])
+            [metabase.task :as task]
             [metabase.util :as u]))
 
+;; order is important here!!  these indexes match the values from clj-times (day-of-week) function
+;; 0 = Sunday, 6 = Saturday
+(def days-of-week ["sun"
+                   "mon"
+                   "tue"
+                   "wed"
+                   "thu"
+                   "fri"
+                   "sat"])
 
-(declare execute report-fail report-complete)
+(declare execute-all-reports
+         execute-if-scheduled
+         execute-and-send
+         execute
+         report-fail
+         report-complete)
+
+(defn execute-all-reports
+  "Execute and Send all `EmailReports` in the system.
+   This function checks the schedule on all :active email reports and runs them if appropriate."
+  []
+  (log/debug "Executing ALL EmailReports")
+  (->> (sel :many :fields [EmailReport :id :schedule] :mode (mode->id :active))
+       (map execute-if-scheduled)))
+
+;; this adds our funtion below onto the hourly task runner
+;; TODO - maybe we should put these in a unified place for all scheduled tasks?
+(task/add-hook! #'task/hourly-tasks-hook execute-all-reports)
+
+(defn- execute-if-scheduled
+  "Test if a given report is scheduled to run at the current time and if so execute it."
+  [{{:keys [days_of_week time_of_day timezone]} :schedule id :id}]
+  (log/debug "Processing: " id days_of_week time_of_day timezone)
+  (let [now (time/to-time-zone (time/now) (time/time-zone-for-id (or timezone "UTC"))) ; NOTE this is in LOCAL timezone
+        curr-hour (time/hour now)
+        curr-weekday (get days-of-week (time/day-of-week now))]
+    ;; report schedule should look like:
+    ;;   `{:days_of_week {:mon true :tue true :wed false ...} :time_of_day "morning" :timezone "US/Pacific"}`
+    (when (and (get days_of_week (keyword curr-weekday))   ; scheduled weekdays include curr-weekday
+               (= curr-hour (time-of-day->realhour time_of_day)))  ; scheduled hour matches curr-hour
+      (try
+        (execute-and-send id)
+        (catch Throwable t
+          (log/error (format "Error executing email report: %d" id) t))))))
 
 (defn execute-and-send
   "Execute and Send an `EmailReport`.  This includes running the data query behind the report, formatting the email,