Changes in Varnish 7.1¶
For information about updating your current Varnish deployment to the new version, see Upgrading to Varnish 7.1.
A more detailed and technical account of changes in Varnish, with links to issues that have been fixed and pull requests that have been merged, may be found in the change log.
varnishd¶
Parameters¶
A new kind of parameters exists: deprecated aliases. Their documentation is minimal, mainly referring to the actual symbols they alias. They are not listed in the CLI, unless referred to explicitly.
There is no deprecated alias yet, but some are already planned for future releases. Alias parameters have next to no overhead when used directly.
The deprecated vsm_space
parameter was removed.
A new cc_warnings
parameter contains a subset of the compiler flags
extracted from cc_command
, which in turn grew new expansions:
%d
: the raw defaultcc_command
%D
: the expanded defaultcc_command
%w
: thecc_warnings
parameter%n
: the working directory (-n
option)
This should facilitate the creation of wrapper scripts around VCL compilation.
There is a new experimental
parameter that is identical to the feature
parameter, except that it guards features that may not be considered complete
or stable. An experimental feature may be promoted to a regular feature or
dropped without being considered a breaking change.
Command line options¶
The deprecated sub-argument of the -l
option was removed, it is now a
shorthand for the vsl_space
parameter only.
The -T
, -M
and -P
command line options can be used multiple times,
instead of retaining only the last occurrence.
When there is no active VCL, the first loaded VCL was always implicitly used
too. This is now only true for VCLs loaded with either the -f
or -b
options, since they imply a vcl.use
. VCL loaded through the Varnish CLI
(vcl.load
or vcl.inline
) via a CLI script loaded through the -I
command line option require an explicit vcl.use
.
Other changes in varnishd¶
ESI includes now support the onerror="continue"
attribute. However, in
order to take effect a new +esi_include_onerror
feature flag needs to be
raised.
Changes to VCL¶
It is now possible to assign a BLOB
value to a BODY
variable,
in addition to STRING
as before.
VCL variables¶
New VCL timestamp variables have been added to track the point in time when HTTP messages were created:
req.time
req_top.time
resp.time
bereq.time
beresp.time
obj.time
The new req.transport
variable returns “HTTP/1” or “HTTP/2” as
appropriate.
Other changes to VCL¶
Where a regular expression literal is expected, it is now possible to have a concatenation of constant strings. It can be useful when part of the expression comes from an environment-specific include, or to break a long expression into multiple lines. (introduced with 7.0.1)
Similarly to varnishd
parameters, it is now possible to have deprecated
aliases of VCL variables. Although there are none so far, aliases will allow
some symbols to be renamed without immediately breaking existing VCL code.
Deprecated VCL aliases have no runtime overhead, they are reified at VCL compile time.
VMODs¶
New STRING strftime(TIME time, STRING format) function for UTC formatting.
It is now possible to declare deprecated aliases of VMOD functions and object
methods, just like VCL aliases. The cookie.format_rfc1123()
function was
renamed to STRING format_date(TIME now, DURATION timedelta), and the former was retained as a
deprecated alias of the latter for compatibility.
Deprecated VMOD aliases have no runtime overhead, they are reified at VCL compile time.
varnishlog¶
It is now possible to write to the standard output with -w -
, to be on par
with the ability to read from the standard input with -r -
. This is not
possible in daemon mode.
In a pipe scenario, the backend transaction emits a Start timestamp and both client and backend transactions emit the Process timestamp.
varnishncsa¶
It is now possible to write to the standard output with -w -
, to be on par
with the ability to read from the standard input with -r -
. This is not
possible in daemon mode.
varnishadm¶
When vcl.show
is invoked without a parameter, it defaults to the active
VCL.
The param.set
command accepts a -j
option. In this case the JSON
output is the same as param.show -j
of the updated parameter.
A new debug.shutdown.delay
command is available in the Varnish CLI for
testing purposes. It can be useful for testing purposes to see how its
environment (service manager, container orchestrator, etc) reacts to a
varnishd
’s child process taking significant time to stop
.
varnishtest¶
The SO_RCVTIMEO_WORKS
feature check is gone. (introduced with 7.0.1)
The reporting of logexpect
events was rearranged for readability.
The abort
command in the logexpect
facility of varnishtest
can now be used to trigger an abort()
to help debugging the vsl
client library code.
The vtc.barrier_sync()
VMOD function can be used in vcl_init
from now
on.
Changes for developers and VMOD authors¶
The SO_RCVTIMEO
and SO_SNDTIMEO
socket options are now
required at build time since their absence would otherwise prevent
some timeouts to take effect. We no longer check whether they
effectively work, hence the removal of the SO_RCVTIMEO_WORKS
feature check in varnishtest
. (introduced with 7.0.1)
Varnish will use libunwind by default when available at configure time, the
--without-unwind
configure flag can prevent this and fall back to
libexecinfo to generate backtraces.
There is a new debug storage backend for testing purposes. So far, it can only be used to ensure that allocation attempts return less space than requested.
There are new C macros for VCL_STRANDS
creation: TOSTRAND()
and
TOSTRANDS()
are available in vrt.h
.
New utility macros vmin[_t]
, vmax[_t]
and vlimit[_t]
available in
vdef.h
.
The fetch and delivery filters should now be registered and unregistered with
VRT_AddFilter()
and VRT_RemoveFilter()
.
Dynamic backends are now reference-counted, and VMOD authors must explicitly
track assignments with VRT_Assign_Backend()
.
The vtc.workspace_reserve()
VMOD function will zero memory from now on.
When the +workspace
debug flag is raised, workspace logs are no longer
emitted as raw logs disconnected from the task. Having workspace logs grouped
with the rest of the task should help workspace footprint analysis.
It is now possible to generate arbitrary log lines with vtc.vsl()
and vtc.vsl_replay()
, which can help testing log processing
utilities.
It is also possible to tweak the VXID cache chunk size per thread pool with
the debug.xid
command for the Varnish CLI, which can also help testing
log processing utilities.
http_IsHdr()
is now exposed as part of the strict ABI for VMODs.
Platform Support¶
CentOS¶
With the End of Life of CentOS 8, we will build el8 packages on almalinux from now on. This means that we will always target the oldest el8 branch. For example a package built for el8.5 is not guaranteed to work on el8.1 even though the latter may still be supported by Red Hat.
systemd¶
The kill mode of the varnish service was changed from process
to mixed
to ensure that the cache process is killed if the manager process is timed out
by systemd. Otherwise, a race exists with the cache process where a restart is
carried on before the old cache process exits, creating conflict on resources
such as listen ports.
eof