varnish 3.x -> varnish 4.x 設定擋 @ Hello World

從varnish 4.x 以後設定檔有大幅度的改變
如果不想一行一行debug 的話，可以使用這個方便的工具
https://github.com/fgsch/varnish3to4

節錄文章的內容

Script to assist migrating a VCL file from Varnish 3 to 4.x. [1]

 $ varnish3to4 -o <filename>.v4 <filename>
 $ diff -u <filename> <filename>.v4

To limit changes for Varnish 4.0:

 $ varnish3to4 -v 4.0 -o <filename>.v4 <filename>
 $ diff -u <filename> <filename>.v4

V3	V4
{bereq,req}.backend.healthy	std.healthy({bereq.backend,req.backend_hint})
{bereq,req}.request	{bereq,req}.method
bereq.* in vcl_pass and vcl_miss	req.*
{beresp,obj,resp}.response	{beresp,obj,resp}.reason
beresp.storage	beresp.storage_hint
{client,server}.port	std.port({client,server}.ip)
error code response	return (synth(code, response))
obj.hits - writing to	-
obj.* in vcl_synth	resp.*
obj.lastuse	-
remove	unset
req.backend	req.backend_hint
req.grace	-
req.* in vcl_backend_response	bereq.*
return (hash) in vcl_hash	return (lookup)
return (hit_for_pass)	set beresp.uncacheable = true; return (deliver);
return (lookup) in vcl_recv	return (hash)
return (pass) in vcl_pass	return (fetch)
return (restart) in vcl_fetch	return (retry)
std.real2integer(..) [2]	std.real2integer(.., n)
std.time2integer(..) [2]	std.time2integer(.., n)
std.time2real(..) [2]	std.time2real(.., n.n)
synthetic ..	synthetic(..)
vcl_error	vcl_backend_error and vcl_synth
vcl_fetch	vcl_backend_response

V3	V4
purge	-

V3	V4
-	vcl 4.0
-	import directors new xx = directors.yy(); xx.add_backend(ss); set req.backend_hint = xx.backend();

Add imports resulting from changes in V4, complete purge handling and any other changes missing from this document.

V4.0	V4.1
return (fetch) in vcl_hit [3]	return (miss)

Comments in VCL are treated as code and as such references within will be rewritten.
Required in 4.1 and above.
Optional in 4.1. Required in 5.0 and above.