Add reader.synth().

README.rst

@@ -67,6 +67,16 @@ cached contents are returned.
 
 XXX ...
 
+.. _xreader.synth():
+
+VOID xreader.synth()
+--------------------
+
+Generate a synthetic client response body from the file contents. This
+method may only be called in ``vcl_synth``.
+
+XXX ...
+
 .. _file.version():
 
 STRING version()

src/tests/synth.vtc

+# looks like -*- vcl -*-
+
+varnishtest "reader.synth()"
+
+shell {echo -n "foo bar baz quux" > ${tmpdir}/synth}
+
+varnish v1 -vcl {
+	import ${vmod_file};
+	backend b { .host = "${bad_ip}"; }
+
+	sub vcl_init {
+		new rdr = file.reader("${tmpdir}/synth", ttl=0.1s);
+	}
+
+	sub vcl_recv {
+		return (synth(200));
+	}
+
+	sub vcl_synth {
+		rdr.synth();
+		return (deliver);
+	}
+} -start
+
+client c1 {
+	txreq
+	rxresp
+	expect resp.status == 200
+	expect resp.body == "foo bar baz quux"
+} -run
+
+shell {echo -n "quux baz bar foo" > ${tmpdir}/synth}
+delay .1
+
+client c1 {
+	txreq
+	rxresp
+	expect resp.status == 200
+	expect resp.body == "quux baz bar foo"
+} -run
+
+shell {rm -f ${tmpdir}/synth}
+delay .1
+
+client c1 {
+	txreq
+	expect_close
+} -run
+
+logexpect l1 -v v1 -d 1 -g vxid -q "VCL_Error" {
+	expect 0 * Begin	req
+	expect * = VCL_Error	{^rdr\.synth\(\): vmod file failure: rdr: cannot read info about}
+	expect * = End
+} -run
+
+shell {touch ${tmpdir}/synth}
+
+varnish v1 -vcl {
+	import ${vmod_file};
+	backend b { .host = "${bad_ip}"; }
+
+	sub vcl_init {
+		new rdr = file.reader("${tmpdir}/synth");
+	}
+
+	sub vcl_recv {
+		rdr.synth();
+	}
+}
+
+logexpect l1 -v v1 -d 0 -g vxid -q "VCL_Error" {
+	expect 0 * Begin	req
+	expect * = VCL_Error	{^rdr\.synth\(\) may only be called in vcl_synth$}
+	expect * = End
+} -start
+
+client c1 {
+	txreq
+	rxresp
+	expect resp.status == 503
+	expect resp.reason == "VCL failed"
+} -run
+
+logexpect l1 -wait

src/vmod_file.c

@@ -473,6 +473,38 @@ vmod_reader_get(VRT_CTX, struct VPFX(file_reader) *rdr)
 	return (rdr->addr);
 }
 
+VCL_VOID
+vmod_reader_synth(VRT_CTX, struct VPFX(file_reader) *rdr)
+{
+	const char *p[0];
+	struct strands strands = { 1, p };
+
+	CHECK_OBJ_NOTNULL(ctx, VRT_CTX_MAGIC);
+	CHECK_OBJ_NOTNULL(rdr, FILE_READER_MAGIC);
+
+	if ((ctx->method & VCL_MET_SYNTH) == 0) {
+		VRT_fail(ctx, "%s.synth() may only be called in vcl_synth",
+			 rdr->vcl_name);
+		return;
+	}
+
+	AZ(pthread_rwlock_rdlock(&rdr->lock));
+	if (rdr->flags & RDR_ERROR) {
+		AN(strcmp(rdr->errbuf, NO_ERR));
+		VRT_fail(ctx, "%s.synth(): %s", rdr->vcl_name, rdr->errbuf);
+		AZ(pthread_rwlock_unlock(&rdr->lock));
+		return;
+	}
+
+	AN(rdr->flags & RDR_MAPPED);
+	AN(rdr->addr);
+	strands.p[0] = rdr->addr;
+	VRT_synth_page(ctx, &strands);
+
+	AZ(pthread_rwlock_unlock(&rdr->lock));
+	return;
+}
+
 VCL_STRING
 vmod_version(VRT_CTX)
 {

src/vmod_file.vcc

@@ -50,6 +50,13 @@ cached contents are returned.
 
 XXX ...
 
+$Method VOID .synth()
+
+Generate a synthetic client response body from the file contents. This
+method may only be called in ``vcl_synth``.
+
+XXX ...
+
 $Function STRING version()
 
 Return the version string for this VMOD.