node.scm (node-loadavg): New procedure

* modules/ssh/dist.scm (with-ssh): Move to (ssh dist node); re-export the
  procedure.
* modules/ssh/dist/node.scm (node-loadavg): New procedure.

2 files changed, 33 insertions, 9 deletions

diff --git a/modules/ssh/dist.scm b/modules/ssh/dist.scm
index 06027dc..dbac7a2 100644
--- a/modules/ssh/dist.scm
+++ b/modules/ssh/dist.scm
@@ -50,8 +50,8 @@
   #:use-module (ssh channel)
   #:use-module (ssh dist node)
   #:use-module (ssh dist job)
-  #:re-export (node? node-session node-repl-port make-node)
-  #:export (distribute dist-map with-ssh rrepl))
+  #:re-export (node? node-session node-repl-port make-node with-ssh)
+  #:export (distribute dist-map rrepl))
 
 
 ;;; Helper procedures
@@ -114,13 +114,6 @@ result of computation."
     results))
 
 
-(define-syntax-rule (with-ssh node exp ...)
-  "Evaluate expressions on a remote REPL using a NODE, return four values: an
-evaluation result, a number of the evaluation, a module name and a language
-name.  Throw 'node-error' or 'node-repl-error' on an error."
-  (node-eval node (quote (begin exp ...))))
-
-
 (define (rrepl node)
   "Start an interactive remote REPL (RREPL) session using NODE."
   (let ((repl-channel (node-open-rrepl node)))
diff --git a/modules/ssh/dist/node.scm b/modules/ssh/dist/node.scm
index f58d9f1..e4926fc 100644
--- a/modules/ssh/dist/node.scm
+++ b/modules/ssh/dist/node.scm
@@ -36,6 +36,9 @@
 ;;   node-run-server
 ;;   node-stop-server
 ;;   node-server-running?
+;;   node-loadavg
+;;   with-ssh
+;;
 ;;   rrepl-eval
 ;;   rrepl-skip-to-prompt
 ;;
@@ -73,6 +76,8 @@
             node-run-server
             node-stop-server
             node-server-running?
+            node-loadavg
+            with-ssh
 
             node-open-rrepl
             rrepl-eval
@@ -370,4 +375,30 @@ procedure returns the 1st evaluated value if multiple values were returned."
     (and (zero? rc)
          (car result))))
 
+
+(define-syntax-rule (with-ssh node exp ...)
+  "Evaluate expressions on a remote REPL using a NODE, return four values: an
+evaluation result, a number of the evaluation, a module name and a language
+name.  Throw 'node-error' or 'node-repl-error' on an error."
+  (node-eval node (quote (begin exp ...))))
+
+(define (node-loadavg node)
+  "Get average load of a NODE.  Return an alist of five elements as described in
+proc(5) man page."
+  (with-ssh node
+    (use-modules (ice-9 rdelim))
+    (define (list-element->number l n)
+      (string->number (list-ref l n)))
+    (let* ((p   (open-input-file "/proc/loadavg"))
+           (raw (read-line p)))
+      (close p)
+      (let ((raw-list (string-split raw #\space)))
+        `((one                 . ,(list-element->number raw-list 0))
+          (five                . ,(list-element->number raw-list 1))
+          (fifteen             . ,(list-element->number raw-list 2))
+          (scheduling-entities . ,(map string->number
+                                       (string-split (list-ref raw-list 3)
+                                                     #\/)))
+          (last-pid            . ,(list-element->number raw-list 4)))))))
+
 ;;; node.scm ends here