diff -r 8259376eee11 -r 1ef551e24009 examples/db/mbdb.lisp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/examples/db/mbdb.lisp	Thu Apr 11 18:58:35 2024 -0400
@@ -0,0 +1,48 @@
+;;; examples/mbdb.lisp --- MusicBrainz Database import and analysis
+
+;; This example show how to migrate a set of complex JSON objects to
+;; RocksDB using a dump from the MusicBrainz database
+;; (https://musicbrainz.org/). The files are hosted at
+;; https://packy.compiler.company/data/mbdump
+
+;;; Code:
+(defpackage :examples/mbdb
+  (:use :cl :std :dat/json :net/fetch :obj/id :rdb :cli/clap :obj/uuid)
+  (:import-from :log :info! :debug!)
+  (:import-from :rocksdb :load-rocksdb)
+  (:export :main))
+
+(in-package :examples/mbdb)
+
+(load-rocksdb t)
+
+(declaim (type pathname *mbdb-path*))
+(defvar *mbdb-path* #P"/tmp/mbdb/")
+(defvar *mbdb* (create-db *mbdb-path* :opts (default-rdb-opts)))
+
+(defvar *mbdump-base-url* "https://packy.compiler.company/data/mbdump/"
+  "Remote location of MusicBrainz JSON data files.")
+
+(defvar *mbdump-files*
+  (mapcar (lambda (f) (make-pathname :name f :type "json" :directory *mbdump-base-url*))
+          (list "area" "artist" "event" "instrument"
+                "label" "place" "recording" "release"
+                "release-group" "series" "work")))
+
+(defun extract-columns (obj)
+  "Extract fields from a JSON-OBJECT, returning a vector of
+  uninitialized column-families which can be created with CREATE-CFS.
+
+Returns multiple values: the list of columns, the id, and type-id if present."
+  (values
+   (mapcar #'car (json-object-members obj))
+   (make-uuid-from-string (json-getf obj "id"))
+   (when-let ((tid (json-getf obj "type-id")))
+     (make-uuid-from-string tid))))
+
+(defmain ()
+  (let ((*default-pathname-defaults* (ensure-directories-exist *mbdb-path* :verbose t)))
+    (log:info! "Welcome to MBDB")
+    (with-db (db *mbdb*)
+      (open-db db)
+      (close-db db))))