global-functions: add $WaitForFile, wait for file on fetch

The fetch command is asynchronous, the file is not guaranteed to be
available when command terminates.

I opened an issue at Mikrotik support (Ticket#2019041722004999),
their answer:

> You should perform a check in a loop.
> :delay until file exist
>
> That can happen also with any configuration not just files.

So add a function to wait for a file with given name.

I have not seen this with other configuration, though.

1 files changed, 4 insertions, 1 deletions

diff --git a/check-certificates b/check-certificates
index bd1e0ed..9dd9acb 100644
--- a/check-certificates
+++ b/check-certificates
@@ -10,6 +10,7 @@
 
 :global SendNotification;
 :global UrlEncode;
+:global WaitForFile;
 
 :local GetIssuerCN do={
   :foreach IssuerI in=$1 do={
@@ -39,7 +40,9 @@
     :foreach Type in={ ".pem"; ".p12" } do={
       :local CertFileName ([ $UrlEncode $CommonName ] . $Type);
       :do {
-        / tool fetch check-certificate=yes-without-crl ($CertRenewUrl . $CertFileName);
+        / tool fetch check-certificate=yes-without-crl \
+            ($CertRenewUrl . $CertFileName) dst-path=$CertFileName;
+        $WaitForFile $CertFileName;
         :foreach PassPhrase in=$CertRenewPass do={
           / certificate import file-name=$CertFileName passphrase=$PassPhrase;
         }