feat: env vars as vectors

resources/config.edn

@@ -1,6 +1,7 @@
 {:webserver/port #long #or [#env PORT 3001]
- :webserver/allowed-origins ["http://docs.clj.codes" "https://docs.clj.codes"
-                             "http://docs-frontend.fly.dev" "https://docs-frontend.fly.dev"]
+ :webserver/allowed-origins #csv #or [#env ALLOWED_ORIGINS
+                                      ["http://docs.clj.codes" "https://docs.clj.codes"
+                                       "http://docs-frontend.fly.dev" "https://docs-frontend.fly.dev"]]
 
  :database {:dbtype "postgres"
             :dbname #or [#env DB_NAME "postgres"]

src/codes/clj/docs/backend/config.clj

@@ -0,0 +1,20 @@
+(ns codes.clj.docs.backend.config
+  (:require [aero.core :as aero]
+            [clojure.string :as string]))
+
+(defn- str-var->vector-var
+  "Converts a string config variable to a vector of strings, when applicable.
+  Environment variables are expected to be set as comma-separated values."
+  [value]
+  (if (string? value)
+    (let [split-configs (-> value
+                            (string/split  #","))
+          env-config (->> split-configs
+                          (map string/trim)
+                          (remove empty?))]
+      env-config)
+    value))
+
+(defmethod aero/reader 'csv
+  [_ _ value]
+  (str-var->vector-var value))

src/codes/clj/docs/backend/server.clj

@@ -1,5 +1,6 @@
 (ns codes.clj.docs.backend.server
   (:require [codes.clj.docs.backend.components.db-docs :as components.db-docs]
+            [codes.clj.docs.backend.config]
             [codes.clj.docs.backend.db.datalevin :refer [read-conn-opts]]
             [codes.clj.docs.backend.routes :as routes]
             [com.stuartsierra.component :as component]

test/resources/csv-config.edn

@@ -0,0 +1,3 @@
+{:some-config #csv #or [#env SOME "value1, value2"]
+ :malformed-config #csv #or [#env MALFORMED "value3,   value4,value5, "]
+ :trailing-comma-config #csv #or [#env TRAILING_COMMA "value6, value7,"]}

test/unit/codes/clj/docs/backend/config_test.clj

@@ -0,0 +1,28 @@
+(ns unit.codes.clj.docs.backend.config-test
+  (:require [aero.core :as aero]
+            [clojure.test :refer [deftest is testing use-fixtures]]
+            [codes.clj.docs.backend.config :as backend.config]
+            [matcher-combinators.test :refer [match?]]
+            [parenthesin.helpers.malli :as helpers.malli]))
+
+(use-fixtures :once helpers.malli/with-intrumentation)
+
+(deftest str-var->vector-var-test
+  (testing "csv configs should be converted to vectors"
+    (is (match? ["value1" "value2"]
+                (#'backend.config/str-var->vector-var "value1, value2"))))
+
+  (testing "trailing and extra whitespaces should be ignored"
+    (is (match? ["value3" "value4" "value5"]
+                (#'backend.config/str-var->vector-var "value3,   value4,value5, "))))
+
+  (testing "trailing commas should be ignored"
+    (is (match? ["value6" "value7"]
+                (#'backend.config/str-var->vector-var "value6, value7,")))))
+
+(deftest csv-reader-test
+  (testing "tag literal #csv should turn comma-separated strings into vectors"
+    (is (match? {:some-config ["value1" "value2"]
+                 :malformed-config ["value3" "value4" "value5"]
+                 :trailing-comma-config ["value6" "value7"]}
+                (aero/read-config "test/resources/csv-config.edn")))))