Initialize cache directories and private database files

README.md

@@ -87,6 +87,11 @@ io.github.latacora/sqlite-cache {:git/url "https://github.com/latacora/sqlite-ca
              :read  {"some-tag" read-handler}}})
 ```
 
+Filesystem `:dbname` paths may include missing parent directories; `cache`
+creates them before opening SQLite. New filesystem databases on POSIX systems
+are created with mode `0600`; existing files keep their permissions. SQLite
+URI paths (`file:...`) and in-memory databases are passed through unchanged.
+
 ### Supported types
 
 The cache uses [transit-canon](https://github.com/latacora/transit-canon) for serialization, so out of the box it supports:

deps.edn

@@ -1,6 +1,7 @@
 {:paths ["src" "resources"]
  :deps
  {org.clojure/clojure {:mvn/version "1.12.4"}
+  babashka/fs {:mvn/version "0.5.22"}
 
   ;; Database
   com.github.seancorfield/next.jdbc {:mvn/version "1.3.1070"}

src/com/latacora/sqlite_cache/core.clj

@@ -14,13 +14,16 @@
   All cache analysis and cleanup (actually deleting expired records and
   VACUUMing afterwards) is done manually (see `maintain!`)."
   (:require
+   [babashka.fs :as fs]
+   [clojure.string :as str]
    [honey.sql.helpers :as h]
    [next.jdbc :as jdbc]
    [com.latacora.sqlite-cache.serialization :as ser]
    [com.latacora.sqlite-cache.db :as db]
    [com.latacora.sqlite-cache.ddl :as ddl]
    [com.latacora.sqlite-cache.maintenance :as maint])
   (:import
+   (java.nio.file FileAlreadyExistsException)
    (java.util.concurrent LinkedBlockingQueue TimeUnit)))
 
 ;; This currently does not use clojure.core.cache, but it probably could stand
@@ -214,11 +217,25 @@
    :ttl default-ttl
    :max-age default-max-age})
 
+(defn- prepare-db-file!
+  [{:keys [dbname]}]
+  (when (and dbname (not= dbname ":memory:")
+             (not (str/starts-with? dbname "file:")))
+    (let [target (fs/absolutize dbname)]
+      (fs/create-dirs (fs/parent target))
+      (try
+        (fs/create-file target {:posix-file-permissions "rw-------"})
+        (catch FileAlreadyExistsException _ nil)
+        ;; Let SQLite use platform defaults when POSIX permissions are unavailable.
+        (catch UnsupportedOperationException _ nil)))))
+
 (defn cache
   "Builds a cache with given opts.
 
   This will ensure the cache is ready to use (has the appropriate schema,
-  indexes, et cetera), and returns a function with the same signature as the
+  indexes, et cetera), creates missing parent directories for filesystem
+  `:dbname` paths, creates new POSIX database files with owner-only access,
+  and returns a function with the same signature as the
   function being cached.
 
   The returned function has metadata containing the full cache configuration,
@@ -245,6 +262,7 @@
     are required for cache-key correctness."
   [opts]
   (let [{:keys [db] :as opts} (merge default-opts opts)
+        _ (prepare-db-file! db)
         read-conn (jdbc/get-connection db)
         write-conn (jdbc/get-connection db)
         write-queue (make-write-queue! write-conn)

test/com/latacora/sqlite_cache/core_test.clj

@@ -1,5 +1,6 @@
 (ns com.latacora.sqlite-cache.core-test
   (:require
+   [babashka.fs :as fs]
    [cognitect.transit :as transit]
    [com.latacora.sqlite-cache.core :as c]
    [com.latacora.sqlite-cache.maintenance :as maint]
@@ -690,3 +691,20 @@
 
         ;; Second call should succeed with the same arguments
         (t/is (= 10 (cached-fn 5)))))))
+
+(t/deftest creates-missing-cache-parent-directories
+  (let [root (fs/create-temp-dir {:prefix "sqlite-cache-parents-"})
+        path (fs/path root "nested" "cache.db")]
+    (try
+      (t/is (not (fs/exists? (fs/parent path))))
+      (let [cached (c/cache {:db {:dbtype "sqlite" :dbname (str path)}
+                            :func inc :func-name "test/parents"})]
+        (t/is (fs/regular-file? path))
+        (when-let [permissions (try
+                                 (fs/posix-file-permissions path)
+                                 (catch UnsupportedOperationException _ nil))]
+          (t/is (= "rw-------" (fs/posix->str permissions))))
+        (t/is (= 2 (cached 1)))
+        (tu/assert-n-entries! cached 1))
+      (finally
+        (fs/delete-tree root)))))