Rotating log file with retention

main.rkt

@@ -7,11 +7,13 @@
          data/queue
          "private/loghash.rkt"
          "private/store.rkt"
+         "private/rotating-file.rkt"
          )
 
 (provide sl-def-log
          sl-log-to
          sl-log-to-file
+         sl-log-to-rotating-file
          sl-log-to-display
          sl-log-to-store
          sl-log-to-file&display
@@ -211,6 +213,24 @@
   (dbg-simple-log "log-to-file enabled with file ~a" filename)
   )
 
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; goal       : Enable daily rotating file logging.
+; pre        : filename is a path string and retention-days is a positive integer.
+; post       : The current day is logged as plain text. Older retained days are
+;              stored as <filename>.YYYY-MM-DD.gz.
+; result     : void
+; internals  : retention-days includes the current, uncompressed day.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+(define (sl-log-to-rotating-file filename [retention-days 7])
+  (unless (exact-positive-integer? retention-days)
+    (raise-argument-error 'sl-log-to-rotating-file
+                          "exact-positive-integer?"
+                          retention-days))
+  (sl-log-to file (make-rotating-log-callback filename retention-days))
+  (dbg-simple-log "rotating log-to-file enabled with file ~a and retention ~a days"
+                  filename retention-days)
+  )
+
 (define-syntax def-log2
   (syntax-rules ()
     ((_ id parent receiver log-callbacks dbgn infon warnn errn fataln syncn)