Initial import

README.md

@@ -1,3 +1,22 @@
 # audio-library-manager
 
-If you have a directory with, e.g. /music with a library containing flac music tracks, this will resample the files to at most 48.000Hz (get rid of the 96Khz/192Khz files that one will never hear the difference to 48Khz). Also there's a flac -> opus conversion path (to e.g. /music-opus) to make a portable library. It will keep the information about the files in /music/.music-info.db.
+First setup for `flac-48khz-manager.rkt`.
+
+The command keeps a FLAC directory tree at a maximum sample rate of 48 kHz.
+Files above the configured threshold are converted in place through a Racket place.
+The conversion path uses `racket-audio/audio-encoder` dynamically, so the package can still compile on systems where the native audio libraries are not installed yet.
+
+Default files below the FLAC root:
+
+- `.music-info.db`: keystore state database
+- `.flac-48khz-manager.ini`: configuration
+- `.flac-48khz-manager.log`: log file
+
+Run:
+
+```sh
+racket flac-48khz-manager.rkt /path/to/flac-tree
+```
+
+Important configuration keys are created automatically in `.flac-48khz-manager.ini`.
+SMTP reports are HTML and only summarize counters and errors.

flac-48khz-manager.rkt

@@ -0,0 +1,125 @@
+#lang racket/base
+
+(require racket/cmdline
+         racket/file
+         racket/list
+         racket/path
+         "private/audio.rkt"
+         "private/config.rkt"
+         "private/convert-place.rkt"
+         "private/hash.rkt"
+         "private/log.rkt"
+         "private/mail.rkt"
+         "private/report.rkt"
+         "private/scan.rkt"
+         "private/state.rkt"
+         "private/util.rkt")
+
+(provide manage-flac-tree
+         summary->lines)
+
+(define (file-info path digest)
+  (list (cons 'digest digest)
+        (cons 'size (file-size path))
+        (cons 'mtime (file-or-directory-modify-seconds path))))
+
+(define (same-file-state? old digest)
+  (and old
+       (equal? (alist-ref/default old 'digest #f) digest)
+       (not (equal? (alist-ref/default old 'status #f) 'error))))
+
+(define (process-one-file ks config path relpath inspect-flac-proc convert-proc summary errors)
+  (define digest (file-digest path (manager-config-hash-algorithm config)))
+  (define old (state-get-file ks relpath #f))
+  (cond [(same-file-state? old digest)
+         (info-alm "unchanged: ~a" relpath)
+         (values (summary-inc (summary-inc summary 'seen) 'unchanged) errors)]
+        [else
+         (define summary1 (summary-inc (summary-inc summary 'seen) 'processed))
+         (define summary2 (if old (summary-inc summary1 'changed) (summary-inc summary1 'new)))
+         (with-handlers ([exn:fail?
+                          (lambda (e)
+                            (err-alm "error for ~a: ~a" relpath (exn-message e))
+                            (state-set-file! ks relpath
+                                             (append (file-info path digest)
+                                                     (list (cons 'status 'error)
+                                                           (cons 'message (exn-message e)))))
+                            (values (summary-inc summary2 'errors)
+                                    (cons (list (cons 'file relpath)
+                                                (cons 'message (exn-message e)))
+                                          errors)))])
+           (define sample-rate (inspect-flac-proc path))
+           (cond [(> sample-rate (manager-config-max-sample-rate config))
+                  (if (manager-config-dry-run? config)
+                      (begin
+                        (warn-alm "dry-run: would convert ~a from ~a Hz to ~a Hz" relpath sample-rate (manager-config-max-sample-rate config))
+                        (state-set-file! ks relpath
+                                         (append (file-info path digest)
+                                                 (list (cons 'status 'dry-run)
+                                                       (cons 'sample-rate sample-rate))))
+                        (values (summary-inc (summary-inc summary2 'skipped) 'dry-run) errors))
+                      (begin
+                        (info-alm "converting ~a from ~a Hz to ~a Hz" relpath sample-rate (manager-config-max-sample-rate config))
+                        (let* ((result (convert-proc path
+                                                     (manager-config-max-sample-rate config)
+                                                     (manager-config-compression-level config)))
+                               (new-digest (file-digest path (manager-config-hash-algorithm config)))
+                               (new-sample-rate (inspect-flac-proc path)))
+                          (state-set-file! ks relpath
+                                           (append (file-info path new-digest)
+                                                   (list (cons 'status 'converted)
+                                                         (cons 'old-sample-rate sample-rate)
+                                                         (cons 'sample-rate new-sample-rate)
+                                                         (cons 'encoder-result result))))
+                          (values (summary-inc summary2 'converted) errors))))]
+                 [else
+                  (info-alm "ok: ~a (~a Hz)" relpath sample-rate)
+                  (state-set-file! ks relpath
+                                   (append (file-info path digest)
+                                           (list (cons 'status 'ok)
+                                                 (cons 'sample-rate sample-rate))))
+                  (values (summary-inc summary2 'ok) errors)]))]))
+
+(define (drop-removed! ks current-relpaths summary)
+  (define current (for/hash ([r (in-list current-relpaths)]) (values r #t)))
+  (for/fold ([s summary]) ([old-rel (in-list (state-known-relpaths ks))])
+    (if (hash-ref current old-rel #f)
+        s
+        (begin
+          (info-alm "removed from state: ~a" old-rel)
+          (state-drop-file! ks old-rel)
+          (summary-inc s 'removed)))))
+
+(define (manage-flac-tree base-directory
+                          #:inspect-flac-proc [inspect-flac-proc inspect-flac-sample-rate]
+                          #:convert-proc [convert-proc convert-flac-to-target-in-place])
+  (define base-dir (simple-form-path base-directory))
+  (unless (directory-exists? base-dir)
+    (raise-argument-error 'manage-flac-tree "existing directory" base-directory))
+  (define config (load-manager-config base-dir))
+  (setup-logging! (manager-config-log-file config) (manager-config-display-log? config))
+  (info-alm "base directory: ~a" base-dir)
+  (info-alm "state file: ~a" (manager-config-state-file config))
+  (info-alm "ini file: ~a" (manager-config-ini-file config))
+  (define ks (open-manager-state (manager-config-state-file config)))
+  (define files (find-flac-files base-dir))
+  (define relpaths (map (lambda (p) (relpath-string base-dir p)) files))
+  (define summary0 (drop-removed! ks relpaths (make-empty-summary)))
+  (define-values (summary errors)
+    (for/fold ([summary summary0] [errors '()]) ([p (in-list files)] [rel (in-list relpaths)])
+      (process-one-file ks config p rel inspect-flac-proc convert-proc summary errors)))
+  (define errors* (reverse errors))
+  (with-handlers ([exn:fail? (lambda (e) (err-alm "mail report failed: ~a" (exn-message e)) (void))])
+    (maybe-send-report-mail config summary errors*))
+  (for ([line (in-list (summary->lines summary))]) (info-alm "summary: ~a" line))
+  summary)
+
+(module+ main
+  (define base-dir #f)
+  (command-line
+   #:program "flac-48khz-manager.rkt"
+   #:args (base-directory)
+   (set! base-dir base-directory))
+  (define summary (manage-flac-tree base-dir))
+  (for ([line (in-list (summary->lines summary))])
+    (displayln line)))

info.rkt

@@ -0,0 +1,16 @@
+#lang info
+
+(define collection "audio-library-manager")
+(define deps '("base"
+               "db-lib"
+               "openssl"
+               "keystore"
+               "simple-ini"
+               "simple-log"
+               "smtp"
+               "racket-sprintf"))
+(define scribblings '(("scribblings/audio-library-manager.scrbl" ())))
+(define build-deps '("rackunit-lib" "scribble-lib" "racket-doc"))
+(define pkg-desc "Audio library maintenance tools for FLAC and Opus trees")
+(define version "0.1")
+(define pkg-authors '(hans-dijkema))

main.rkt

@@ -0,0 +1,6 @@
+#lang racket/base
+
+(require "flac-48khz-manager.rkt")
+
+(provide manage-flac-tree
+         summary->lines)

private/audio.rkt

@@ -0,0 +1,16 @@
+#lang racket/base
+
+(provide inspect-flac-sample-rate)
+
+(define (inspect-flac-sample-rate path)
+  (define call-with-id3-tags (dynamic-require 'racket-audio/taglib 'call-with-id3-tags))
+  (define tags-valid? (dynamic-require 'racket-audio/taglib 'tags-valid?))
+  (define tags-sample-rate (dynamic-require 'racket-audio/taglib 'tags-sample-rate))
+  (define sr
+    (call-with-id3-tags path
+      (lambda (tags)
+        (and (tags-valid? tags) (tags-sample-rate tags)))
+      #:mode 'read))
+  (unless (and (integer? sr) (positive? sr))
+    (error 'inspect-flac-sample-rate "cannot determine sample rate for ~a" path))
+  sr)

private/config.rkt

@@ -0,0 +1,105 @@
+#lang racket/base
+
+(require racket/file
+         racket/path
+         simple-ini
+         "util.rkt")
+
+(provide manager-config?
+         manager-config-base-dir
+         manager-config-ini-file
+         manager-config-state-file
+         manager-config-log-file
+         manager-config-max-sample-rate
+         manager-config-hash-algorithm
+         manager-config-dry-run?
+         manager-config-display-log?
+         manager-config-compression-level
+         manager-config-mail-enabled?
+         manager-config-mail-send-on-success?
+         manager-config-mail-send-on-error?
+         manager-config-mail-host
+         manager-config-mail-port
+         manager-config-mail-tls?
+         manager-config-mail-username
+         manager-config-mail-password
+         manager-config-mail-from
+         manager-config-mail-to
+         manager-config-mail-cc
+         manager-config-mail-bcc
+         manager-config-mail-subject-prefix
+         load-manager-config
+         ensure-default-config!)
+
+(struct manager-config
+  (base-dir ini-file state-file log-file max-sample-rate hash-algorithm dry-run?
+            display-log? compression-level mail-enabled? mail-send-on-success?
+            mail-send-on-error? mail-host mail-port mail-tls? mail-username
+            mail-password mail-from mail-to mail-cc mail-bcc mail-subject-prefix)
+  #:transparent)
+
+(define (default-log-file base-dir)
+  (build-path base-dir ".flac-48khz-manager.log"))
+
+(define (default-ini base-dir)
+  (build-path base-dir ".flac-48khz-manager.ini"))
+
+(define (default-state base-dir)
+  (build-path base-dir ".music-info.db"))
+
+(define (ensure-default-config! ini-file)
+  (unless (file-exists? ini-file)
+    (define ini (make-ini))
+    (ini-set! ini 'manager 'max-sample-rate 48000)
+    (ini-set! ini 'manager 'hash-algorithm "sha256")
+    (ini-set! ini 'manager 'dry-run #f)
+    (ini-set! ini 'manager 'display-log #t)
+    (ini-set! ini 'manager 'log-file ".flac-48khz-manager.log")
+    (ini-set! ini 'manager 'compression-level 5)
+    (ini-set! ini 'mail 'enabled #f)
+    (ini-set! ini 'mail 'send-on-success #f)
+    (ini-set! ini 'mail 'send-on-error #t)
+    (ini-set! ini 'mail 'host "")
+    (ini-set! ini 'mail 'port 25)
+    (ini-set! ini 'mail 'tls #f)
+    (ini-set! ini 'mail 'username "")
+    (ini-set! ini 'mail 'password "")
+    (ini-set! ini 'mail 'from "")
+    (ini-set! ini 'mail 'to "")
+    (ini-set! ini 'mail 'cc "")
+    (ini-set! ini 'mail 'bcc "")
+    (ini-set! ini 'mail 'subject-prefix "[flac-48khz-manager]")
+    (ini->file ini ini-file)))
+
+(define (resolve-log-file base-dir v)
+  (define p (string-value v ".flac-48khz-manager.log"))
+  (cond [(path-string? p)
+         (define bp (string->path p))
+         (if (absolute-path? bp) bp (build-path base-dir bp))]
+        [else (default-log-file base-dir)]))
+
+(define (load-manager-config base-dir*)
+  (define base-dir (simple-form-path base-dir*))
+  (define ini-file (default-ini base-dir))
+  (ensure-default-config! ini-file)
+  (define ini (file->ini ini-file))
+  (define log-file (resolve-log-file base-dir (ini-get ini 'manager 'log-file ".flac-48khz-manager.log")))
+  (manager-config base-dir ini-file (default-state base-dir) log-file
+                  (int-value (ini-get ini 'manager 'max-sample-rate 48000) 48000)
+                  (string-downcase (string-value (ini-get ini 'manager 'hash-algorithm "sha256") "sha256"))
+                  (bool-value (ini-get ini 'manager 'dry-run #f) #f)
+                  (bool-value (ini-get ini 'manager 'display-log #t) #t)
+                  (int-value (ini-get ini 'manager 'compression-level 5) 5)
+                  (bool-value (ini-get ini 'mail 'enabled #f) #f)
+                  (bool-value (ini-get ini 'mail 'send-on-success #f) #f)
+                  (bool-value (ini-get ini 'mail 'send-on-error #t) #t)
+                  (string-value (ini-get ini 'mail 'host "") "")
+                  (int-value (ini-get ini 'mail 'port 25) 25)
+                  (bool-value (ini-get ini 'mail 'tls #f) #f)
+                  (string-value (ini-get ini 'mail 'username "") "")
+                  (string-value (ini-get ini 'mail 'password "") "")
+                  (string-value (ini-get ini 'mail 'from "") "")
+                  (split-addresses (ini-get ini 'mail 'to ""))
+                  (split-addresses (ini-get ini 'mail 'cc ""))
+                  (split-addresses (ini-get ini 'mail 'bcc ""))
+                  (string-value (ini-get ini 'mail 'subject-prefix "[flac-48khz-manager]") "[flac-48khz-manager]")))

private/convert-place.rkt

@@ -0,0 +1,46 @@
+#lang racket/base
+
+(require racket/file
+         racket/path
+         racket/place
+         "util.rkt")
+
+(provide convert-flac-to-target-in-place)
+
+(define (temp-output-path input-path)
+  (define-values (base name dir?) (split-path input-path))
+  (define name-str (path->string name))
+  (build-path base (format ".~a.tmp-~a.flac" name-str (current-inexact-milliseconds))))
+
+(define (settings->alist max-sample-rate compression-level)
+  (list (cons 'target-sample-rate max-sample-rate)
+        (cons 'compression-level compression-level)))
+
+(define (convert-flac-to-target-in-place input-path max-sample-rate compression-level)
+  (define tmp-path (temp-output-path input-path))
+  (define worker
+    (place ch
+      (define msg (place-channel-get ch))
+      (define in-file (list-ref msg 0))
+      (define out-file (list-ref msg 1))
+      (define settings (list-ref msg 2))
+      (with-handlers ([exn:fail?
+                       (lambda (e)
+                         (place-channel-put ch (list 'error (exn-message e))))])
+        (define audio-encode (dynamic-require 'racket-audio/audio-encoder 'audio-encode))
+        (define result (audio-encode in-file out-file (make-immutable-hash settings)
+                                     #:encoder 'flac
+                                     #:copy-tags? #t))
+        (place-channel-put ch (list 'ok result)))))
+  (place-channel-put worker (list (path->string input-path)
+                                  (path->string tmp-path)
+                                  (settings->alist max-sample-rate compression-level)))
+  (define response (place-channel-get worker))
+  (cond [(and (pair? response) (eq? (car response) 'ok))
+         (rename-file-or-directory tmp-path input-path #t)
+         (cadr response)]
+        [else
+         (when (file-exists? tmp-path) (delete-file tmp-path))
+         (error 'convert-flac-to-target-in-place "conversion failed for ~a: ~a"
+                input-path
+                (if (and (pair? response) (pair? (cdr response))) (cadr response) response))]))

private/hash.rkt

@@ -0,0 +1,20 @@
+#lang racket/base
+
+(require openssl/sha1
+         openssl/md5)
+
+(provide file-digest)
+
+(define (digest->string v)
+  (cond [(bytes? v) (bytes->hex-string v)]
+        [(string? v) v]
+        [else (format "~a" v)]))
+
+(define (file-digest path [algorithm "sha256"])
+  (define alg (string-downcase (format "~a" algorithm)))
+  (call-with-input-file path
+    (lambda (in)
+      (cond [(member alg '("sha256" "sha-256" "sha2")) (digest->string (sha256-bytes in))]
+            [(member alg '("md5")) (digest->string (md5 in))]
+            [else (error 'file-digest "unsupported digest algorithm: ~a" algorithm)]))
+    #:mode 'binary))

private/log.rkt

@@ -0,0 +1,22 @@
+#lang racket/base
+
+(require racket/file
+         simple-log)
+
+(provide setup-logging!
+         dbg-alm
+         info-alm
+         warn-alm
+         err-alm
+         fatal-alm
+         sync-log-alm)
+
+(sl-def-log audio-library-manager alm)
+
+(define (setup-logging! log-file display-log?)
+  (make-directory* (let-values ([(base name dir?) (split-path log-file)]) base))
+  (if display-log?
+      (sl-log-to-file&display log-file)
+      (sl-log-to-file log-file))
+  (sl-set-log-level 'debug)
+  (info-alm "logging initialized: ~a" log-file))

private/mail.rkt

@@ -0,0 +1,33 @@
+#lang racket/base
+
+(require smtp
+         "config.rkt"
+         "report.rkt")
+
+(provide maybe-send-report-mail)
+
+(define (maybe-send-report-mail config summary errors)
+  (define has-errors? (positive? (summary-ref summary 'errors 0)))
+  (define should-send?
+    (and (manager-config-mail-enabled? config)
+         (not (null? (manager-config-mail-to config)))
+         (or (and has-errors? (manager-config-mail-send-on-error? config))
+             (and (not has-errors?) (manager-config-mail-send-on-success? config)))))
+  (when should-send?
+    (define subject (format "~a FLAC 48 kHz manager: ~a error(s), ~a converted"
+                            (manager-config-mail-subject-prefix config)
+                            (summary-ref summary 'errors 0)
+                            (summary-ref summary 'converted 0)))
+    (define body (html-report subject summary errors))
+    (define mail (make-mail subject body
+                            #:from (manager-config-mail-from config)
+                            #:to (manager-config-mail-to config)
+                            #:cc (manager-config-mail-cc config)
+                            #:bcc (manager-config-mail-bcc config)
+                            #:body-content-type "text/html"))
+    (send-smtp-mail mail
+                    #:host (manager-config-mail-host config)
+                    #:port (manager-config-mail-port config)
+                    #:tls-encode (manager-config-mail-tls? config)
+                    #:username (manager-config-mail-username config)
+                    #:password (manager-config-mail-password config))))

private/report.rkt

@@ -0,0 +1,57 @@
+#lang racket/base
+
+(require racket/list
+         racket/string
+         "util.rkt")
+
+(provide make-empty-summary
+         summary-inc
+         summary-set
+         summary-ref
+         summary->lines
+         html-report)
+
+(define summary-keys '(seen processed new changed unchanged ok converted removed skipped errors dry-run))
+
+(define (make-empty-summary)
+  (append (for/list ([k (in-list summary-keys)]) (cons k 0))
+          (list (cons 'error-list '()))))
+
+(define (summary-ref summary key [default 0])
+  (alist-ref/default summary key default))
+
+(define (summary-set summary key value)
+  (alist-set summary key value))
+
+(define (summary-inc summary key [amount 1])
+  (summary-set summary key (+ (summary-ref summary key 0) amount)))
+
+(define (summary->lines summary)
+  (for/list ([k (in-list summary-keys)])
+    (format "~a: ~a" k (summary-ref summary k 0))))
+
+(define (html-escape s)
+  (define x (format "~a" s))
+  (define y (regexp-replace* #rx"&" x "&"))
+  (define z (regexp-replace* #rx"<" y "&lt;"))
+  (regexp-replace* #rx">" z "&gt;"))
+
+(define (html-report title summary errors)
+  (define rows
+    (apply string-append
+           (for/list ([k (in-list summary-keys)])
+             (format "<tr><th style=\"text-align:left;padding:4px 10px 4px 0\">~a</th><td style=\"text-align:right;padding:4px\">~a</td></tr>"
+                     (html-escape k) (summary-ref summary k 0)))))
+  (define error-html
+    (if (null? errors)
+        "<p>No errors were reported.</p>"
+        (string-append
+         "<h2>Errors</h2><table border=\"1\" cellspacing=\"0\" cellpadding=\"4\"><tr><th>File</th><th>Error</th></tr>"
+         (apply string-append
+                (for/list ([e (in-list errors)])
+                  (format "<tr><td>~a</td><td><pre style=\"white-space:pre-wrap\">~a</pre></td></tr>"
+                          (html-escape (alist-ref/default e 'file ""))
+                          (html-escape (alist-ref/default e 'message "")))))
+         "</table>")))
+  (format "<!doctype html><html><head><meta charset=\"utf-8\"><title>~a</title></head><body><h1>~a</h1><h2>Summary</h2><table>~a</table>~a</body></html>"
+          (html-escape title) (html-escape title) rows error-html))

private/scan.rkt

@@ -0,0 +1,12 @@
+#lang racket/base
+
+(require racket/file
+         racket/list
+         "util.rkt")
+
+(provide find-flac-files)
+
+(define (find-flac-files base-dir)
+  (sort (find-files flac-path? base-dir)
+        string<?
+        #:key path->string))

private/state.rkt

@@ -0,0 +1,33 @@
+#lang racket/base
+
+(require racket/string
+         keystore)
+
+(provide open-manager-state
+         file-state-key
+         state-get-file
+         state-set-file!
+         state-drop-file!
+         state-known-relpaths)
+
+(define prefix "flac-48khz:file:")
+
+(define (open-manager-state state-file)
+  (ks-open state-file))
+
+(define (file-state-key relpath)
+  (string-append prefix relpath))
+
+(define (state-get-file ks relpath [default #f])
+  (ks-get ks (file-state-key relpath) default))
+
+(define (state-set-file! ks relpath value)
+  (ks-set! ks (file-state-key relpath) value))
+
+(define (state-drop-file! ks relpath)
+  (ks-drop! ks (file-state-key relpath)))
+
+(define (state-known-relpaths ks)
+  (map (lambda (k)
+         (substring k (string-length prefix)))
+       (ks-keys-glob ks (string-append prefix "*"))))

private/util.rkt

@@ -0,0 +1,65 @@
+#lang racket/base
+
+(require racket/file
+         racket/list
+         racket/path
+         racket/string)
+
+(provide bool-value
+         int-value
+         string-value
+         split-addresses
+         relpath-string
+         flac-path?
+         ensure-parent-directory!
+         alist-ref/default
+         alist-set)
+
+(define (bool-value v [default #f])
+  (cond [(boolean? v) v]
+        [(number? v) (not (zero? v))]
+        [(string? v)
+         (define s (string-downcase (string-trim v)))
+         (cond [(member s '("#t" "true" "yes" "y" "1" "on")) #t]
+               [(member s '("#f" "false" "no" "n" "0" "off" "")) #f]
+               [else default])]
+        [else default]))
+
+(define (int-value v [default 0])
+  (cond [(integer? v) v]
+        [(number? v) (inexact->exact (round v))]
+        [(string? v) (or (string->number (string-trim v)) default)]
+        [else default]))
+
+(define (string-value v [default ""])
+  (cond [(string? v) v]
+        [(symbol? v) (symbol->string v)]
+        [(number? v) (number->string v)]
+        [(boolean? v) (if v "#t" "#f")]
+        [(not v) default]
+        [else (format "~a" v)]))
+
+(define (split-addresses v)
+  (define s (string-value v ""))
+  (filter (lambda (x) (not (string=? x "")))
+          (map string-trim (regexp-split #px"[,;]" s))))
+
+(define (relpath-string base p)
+  (path->string (find-relative-path (simple-form-path base) (simple-form-path p))))
+
+(define (flac-path? p)
+  (and (file-exists? p)
+       (let-values ([(base name dir?) (split-path p)])
+         (and (path? name)
+              (string-ci=? (bytes->string/utf-8 (or (path-get-extension name) #"")) ".flac")))))
+
+(define (ensure-parent-directory! p)
+  (define-values (base name dir?) (split-path p))
+  (when (path? base) (make-directory* base)))
+
+(define (alist-ref/default a k [default #f])
+  (define e (assoc k a))
+  (if e (cdr e) default))
+
+(define (alist-set a k v)
+  (cons (cons k v) (filter (lambda (e) (not (equal? (car e) k))) a)))

scribblings/audio-library-manager.scrbl

@@ -0,0 +1,79 @@
+#lang scribble/manual
+
+@(require (for-label racket/base
+                     (file "../main.rkt")))
+
+@title{audio-library-manager}
+@author{Hans Dijkema}
+
+The @racketmodname[audio-library-manager] package contains command-line tools for
+maintaining audio library trees.
+
+@section{FLAC 48 kHz manager}
+
+The first tool is @filepath{flac-48khz-manager.rkt}. It keeps a FLAC tree at a
+maximum sample rate of 48 kHz. Files with a higher sample rate are converted in
+place through a worker place. The conversion path uses
+@racketmodname[racket-audio/audio-encoder] dynamically, so the manager module can
+still be compiled on systems where the native audio libraries are not available.
+
+Run the manager as:
+
+@verbatim{racket flac-48khz-manager.rkt <base-directory>}
+
+The manager creates these files below @filepath{<base-directory>}:
+
+@itemlist[
+ @item{@filepath{.music-info.db}: keystore database with file state.}
+ @item{@filepath{.flac-48khz-manager.ini}: configuration.}
+ @item{@filepath{.flac-48khz-manager.log}: log file.}]
+
+@section{Configuration}
+
+The configuration file is created automatically when it does not exist. The main
+settings are:
+
+@verbatim{
+[manager]
+max-sample-rate=48000
+hash-algorithm="sha256"
+dry-run=#f
+display-log=#t
+log-file=".flac-48khz-manager.log"
+compression-level=5
+
+[mail]
+enabled=#f
+send-on-success=#f
+send-on-error=#t
+host=""
+port=25
+tls=#f
+username=""
+password=""
+from=""
+to=""
+cc=""
+bcc=""
+subject-prefix="[flac-48khz-manager]"
+}
+
+When mail is enabled, the report is sent as HTML. The message contains the
+summary counters and the error table; it does not dump the full log by default.
+
+@section{Library API}
+
+@defproc[(manage-flac-tree
+          [base-directory path-string?]
+          [#:inspect-flac-proc inspect-flac-proc procedure? inspect-flac-sample-rate]
+          [#:convert-proc convert-proc procedure? convert-flac-to-target-in-place])
+         list?]{
+Scans @racket[base-directory], updates the keystore state, converts FLAC files
+above the configured maximum sample rate, sends the optional HTML mail report,
+and returns a summary association list.
+
+The keyword arguments are intended for tests and dry integration work. In normal
+use, the default inspector and converter are used.}
+
+@defproc[(summary->lines [summary list?]) (listof string?)]{
+Formats the summary association list as display lines.}

test/flac-48khz-manager-test.rkt

@@ -0,0 +1,47 @@
+#lang racket/base
+
+(require rackunit
+         racket/file
+         racket/path
+         "../flac-48khz-manager.rkt")
+
+(define tmp (make-temporary-file "alm-test-~a" 'directory))
+(define hi (build-path tmp "hires.flac"))
+(define cd (build-path tmp "cd.flac"))
+(call-with-output-file hi #:exists 'replace (lambda (out) (display "hires" out)))
+(call-with-output-file cd #:exists 'replace (lambda (out) (display "cd" out)))
+
+(define convert-count 0)
+
+(define (mock-inspect p)
+  (define s (file->string p))
+  (cond [(regexp-match? #rx"converted" s) 48000]
+        [(regexp-match? #rx"hires" s) 96000]
+        [else 44100]))
+
+(define (mock-convert p rate compression)
+  (set! convert-count (add1 convert-count))
+  (call-with-output-file p #:exists 'replace
+    (lambda (out) (fprintf out "converted to ~a compression ~a" rate compression)))
+  (list (cons 'mock #t) (cons 'target-sample-rate rate)))
+
+(define first-summary
+  (manage-flac-tree tmp #:inspect-flac-proc mock-inspect #:convert-proc mock-convert))
+(check-equal? (assoc 'seen first-summary) '(seen . 2))
+(check-equal? (assoc 'new first-summary) '(new . 2))
+(check-equal? (assoc 'converted first-summary) '(converted . 1))
+(check-equal? convert-count 1)
+
+(define second-summary
+  (manage-flac-tree tmp #:inspect-flac-proc mock-inspect #:convert-proc mock-convert))
+(check-equal? (assoc 'seen second-summary) '(seen . 2))
+(check-equal? (assoc 'unchanged second-summary) '(unchanged . 2))
+(check-equal? convert-count 1)
+
+(delete-file cd)
+(define third-summary
+  (manage-flac-tree tmp #:inspect-flac-proc mock-inspect #:convert-proc mock-convert))
+(check-equal? (assoc 'removed third-summary) '(removed . 1))
+(check-equal? (assoc 'unchanged third-summary) '(unchanged . 1))
+
+(delete-directory/files tmp)