Add the .check() method.

README.rst

@@ -377,6 +377,34 @@ Example::
 
 .. _reader.error():
 
+.. _xreader.check():
+
+VOID xreader.check()
+--------------------
+
+Run a synchronous check of the file, and update the cached contents if
+the file has been changed. This is the same check that runs
+periodically in the background after the reader object is created.
+
+Since the file check does not scale well, this method should be used
+judiciously as a part of request processing. A reasonable use case is
+an administrative request with restricted access, to be called as a
+part of an automated process when the underlying file is changed, so
+that the changes are reflected promptly.
+
+Example::
+
+  if (req.url == "/update-files") {
+	# Assume that this ACL defines internal admin networks.
+	# Return error status 403 Forbidden if the client IP doesn't
+	# match.
+	if (client.ip !~ admin_network) {
+		return (synth(403));
+	}
+	# Internal admins may run a synchronous file check.
+	rdr.check();
+  }
+
 .. _xreader.error():
 
 BOOL xreader.error()

src/Makefile.am

@@ -33,7 +33,8 @@ TESTS = \
 	vtc/info.vtc \
 	vtc/path.vtc \
 	vtc/synth.vtc \
-	vtc/temperature.vtc
+	vtc/temperature.vtc \
+	vtc/check.vtc
 
 # Documentation
 

src/vmod_file.c

@@ -650,6 +650,18 @@ vmod_reader_blob(VRT_CTX, struct VPFX(file_reader) *rdr)
 	return (blob);
 }
 
+VCL_VOID
+vmod_reader_check(VRT_CTX, struct VPFX(file_reader) *rdr)
+{
+	union sigval val;
+
+	CHECK_OBJ_NOTNULL(ctx, VRT_CTX_MAGIC);
+	CHECK_OBJ_NOTNULL(rdr, FILE_READER_MAGIC);
+
+	val.sival_ptr = rdr;
+	check(val);
+}
+
 VCL_BOOL
 vmod_reader_error(VRT_CTX, struct VPFX(file_reader) *rdr)
 {

src/vmod_file.vcc

@@ -354,6 +354,31 @@ Example::
 
 .. _reader.error():
 
+$Method VOID .check()
+
+Run a synchronous check of the file, and update the cached contents if
+the file has been changed. This is the same check that runs
+periodically in the background after the reader object is created.
+
+Since the file check does not scale well, this method should be used
+judiciously as a part of request processing. A reasonable use case is
+an administrative request with restricted access, to be called as a
+part of an automated process when the underlying file is changed, so
+that the changes are reflected promptly.
+
+Example::
+
+  if (req.url == "/update-files") {
+	# Assume that this ACL defines internal admin networks.
+	# Return error status 403 Forbidden if the client IP doesn't
+	# match.
+	if (client.ip !~ admin_network) {
+		return (synth(403));
+	}
+	# Internal admins may run a synchronous file check.
+	rdr.check();
+  }
+
 $Method BOOL .error()
 
 Return true if and only if an error condition was determined the last

src/vtc/check.vtc

+# looks like -*- vcl -*-
+
+varnishtest ".check() method"
+
+shell {echo -n "foo bar baz quux" > ${tmpdir}/file}
+
+varnish v1 -vcl {
+	import file;
+	backend b None;
+
+	sub vcl_init {
+		# Set a long TTL so that the background check
+		# doesn't run during the test.
+		new rdr = file.reader("${tmpdir}/file", ttl=1y);
+	}
+
+	sub vcl_recv {
+		if (req.url == "/check") {
+			rdr.check();
+		}
+		return (synth(200));
+	}
+
+	sub vcl_synth {
+		set resp.http.Get = rdr.get();
+		return (deliver);
+	}
+} -start
+
+client c1 {
+	txreq
+	rxresp
+	expect resp.status == 200
+	expect resp.http.Get == "foo bar baz quux"
+} -run
+
+shell {echo -n "quux baz bar foo" > ${tmpdir}/file}
+
+client c1 {
+	txreq -url "/check"
+	rxresp
+	expect resp.status == 200
+	expect resp.http.Get == "quux baz bar foo"
+} -run