Upgrading to Varnish Cache 9.0

This document only lists breaking changes that you should be aware of when upgrading from Varnish Cache 8.x to Varnish Cache 9.0. For a complete list of changes, please refer to the change log and Changes in Varnish Cache 9.0.

varnishd#

VSV00018#

The handling of HTTP/1.1 requests to an “absolute form” URI has been fixed to also cover the case where the absolute form has an empty path component:

Previously, a request with an empty path like GET http://example.com HTTP/1.1 would cause req.url to contain http://example.com and the Host: header to remain unchanged. This has now been fixed:

• req.url gets set to * if the request method is OPTIONS and to / otherwise
• The Host: header gets set to example.com.

For an empty path with query parameters like http://example.com?/foo, req.url gets normalized by addition of the leading slash. For the example, req.url would contain /?/foo.

For requests to an absolute form URI, the host field is now required. Requests without a host field are rejected with a Status 400 error.

The built-in VCL has been changed to require req.url to start with /, unless the request method is CONNECT or OPTIONS. For CONNECT, no additional check is applied, but CONNECT is not allowed by default. For OPTIONS, * is also allowed.

VCL variable beresp.storage_hint removed#

The VCL variable beresp.storage_hint has been removed. If you were using this variable in your VCL, you will need to remove any references to it.

VCL variable req.ttl deprecated#

The req.ttl variable has been renamed to req.max_age for clarity. req.ttl is retained as an alias and continues to work, but is now deprecated and will be removed in a future version of Varnish Cache. You should update your VCL to use req.max_age instead.

Content-Length handling for requests without body#

For requests having no request body, the Content-Length header will now only be unset when the request method is one of: GET, HEAD, DELETE, OPTIONS, TRACE. For other methods, a Content-Length header with value 0 will be set instead. This may affect backends that are sensitive to the presence of the Content-Length header.

Upgrade notes for VMOD developers#

VSL_Setup() replaced with VSL_Init() and VSL_Alloc()#

VSL_Setup() has been replaced with two new functions:

• VSL_Init() to initialize caller-provided space as a VSL buffer
• VSL_Alloc() to allocate the default vsl_buffer on the heap

VSL_Free() has been added to free the memory allocated by VSL_Alloc().

The coccinelle script tools/coccinelle/vsl_setup_retire.cocci can be used to partially automate the transition (it does not add VSL_Free() calls).