remapStringRewriter matches a record name against orig and its sub domains. The
sub domain check was strings.HasSuffix(src, "."+r.orig), which built the
dot-prefixed string on every call and threw it away. Match the label boundary by
index instead: src is a sub domain of orig when orig sits at the end of src with
a "." immediately before it, which is exactly what the HasSuffix call tested.
Go concatenates short strings into a 32-byte stack buffer, so "."+orig only
reached the heap once orig passed 31 bytes. Below that the temporary was free
and this saves a few ns per record. Above it, 48 B was allocated per record.
Kubernetes service names are past the threshold -
my-service.my-namespace.svc.cluster.local. is 42 bytes - and those are the names
an auto rule rewrites to when a Corefile maps an external name onto an
in-cluster one. orig is the name the question was rewritten to, so whether a
deployment sees the allocation is a property of its Corefile, not its queries.
Caching "."+orig on the rewriter instead does not work: responseRuleFor
constructs a new rewriter for every request an auto name rule rewrites, so the
concatenation would run once per request rather than once per rule, and escapes
to the heap from there. That buys per-record work with a per-request allocation
and regresses every response short enough not to amortize it.
Per record, one rewriteString call on an existing rewriter:
name master this PR
RemapStringRewriter/short/match 186.6n 16 B/1 120.4n 16 B/1 -35%
RemapStringRewriter/short/nomatch 61.5n 0 B/0 16.5n 0 B/0 -73%
RemapStringRewriter/long/match 381.9n 72 B/2 165.3n 24 B/1 -57%
RemapStringRewriter/long/nomatch 219.1n 48 B/1 18.7n 0 B/0 -91%
Per request - rewrite the question, build the response rules, apply them to the
answer:
name master this PR
AutoNameRuleResponse/exact 935n 96 B/4 945n 96 B/4 ~
AutoNameRuleResponse/subdomain 1.248µ 112 B/5 1.242µ 112 B/5 ~
AutoNameRuleResponse/nomatch 1.016µ 96 B/4 945n 96 B/4 -7%
AutoNameRuleResponse/subdomain-8 3.376µ 224 B/12 2.891µ 224 B/12 -14%
AutoNameRuleResponse/k8s/subdomain 1.611µ 176 B/6 1.380µ 128 B/5 -14%
AutoNameRuleResponse/k8s/subdomain-8 5.144µ 672 B/20 3.305µ 288 B/12 -36%
benchstat over 8 runs, i7-1065G7. With short names this is flat at the request
level: one rewriteString call is small next to the four allocations that
building the rules costs. The saving is per record and per byte of name, so it
shows up where responses carry several records and the rewritten-to name is
long.
This applies to exact, prefix, substring and regex name rules with answer auto.
suffix rules build a suffixStringRewriter instead and are not affected.
TestRemapStringRewriter pins the label boundary semantics the index arithmetic
now carries, notably that notexample.com. is not a sub domain of example.com.
It passes against the previous implementation too.
Signed-off-by: Manuel Rüger <manuel@rueg.eu>
- Added nolint to plugin/auto/walk.go to avoid a symlink/TOCTOU
warning, as it needs to follow symlink.
- Replaced a few flagged integer conversions with safe equivalents in
cache hashing, reuseport socket setup, and TLS arg handling
- Preallocated response rule slices in plugin/rewrite/name.go
- Replaced WriteString(fmt.Sprintf/Sprintln(...)) with direct
fmt.Fprint* calls
- Removed stale nolint directives from code and tests that are no
longer needed
Signed-off-by: Ville Vesilehto <ville@vesilehto.fi>
Update to the latest golangci-lint version and use built-in modernize
linter, instead of a custom CI step.
Signed-off-by: Ville Vesilehto <ville@vesilehto.fi>
Replace naked returns with explicit return values to satisfy nakedret
linter and improve readability.
Signed-off-by: Ville Vesilehto <ville@vesilehto.fi>
Enable intrange linter to enforce modern Go range syntax over
traditional for loops, by converting:
for i := 0; i < n; i++
to:
for i := range n
Adding type conversions where needed for compatibility
with existing uint64 parameters.
Signed-off-by: Ville Vesilehto <ville@vesilehto.fi>
* plugin/rewrite: streamline the ResponseRule handling.
The functionality of a response rule is now completely encapsulated behind
a `ResponseRule` interface. This significantly simplifies the complete
processing flow, it enables more flexible response handling and it is possible
to eliminate lots of state flags, ifs and switches.
Based on the new flexibility the pull request also enables to support a
response name rewrite for all name rewrite types.
To be compatible, an explicit `answer auto` option is added to support
a best effort response rewrite (name and value).
Additionally now all name rewrite rules support additional name and value
reponse rewrite options.
Using this feature it is also possible now to rewrite a complete sub domain
hierarchy to a single domain name combined with a correct rewrite (#2389).
Signed-off-by: Uwe Krueger <uwe.krueger@sap.com>
* revert policy
Signed-off-by: Uwe Krueger <uwe.krueger@sap.com>
Co-authored-by: Miek Gieben <miek@miek.nl>
* Rewrite plugin - rewrite SRV targets and names in response answer and additional records
Signed-off-by: Nic Colledge <nic@njcolledge.net>
* Added README content to describe new behaviour
Signed-off-by: Nic Colledge <nic@njcolledge.net>
* Added more record types to rewrite handling based on PR/Issue feedback
Signed-off-by: Nic Colledge <nic@njcolledge.net>
* Updated README.md for plugin
Signed-off-by: Nic Colledge <nic@njcolledge.net>
* Updated unit tests.
Small refactor of getTarget... function.
Signed-off-by: Nic Colledge <nic@njcolledge.net>
* Refactor to add response value rewrite as answer value option
Signed-off-by: Nic Colledge <nic@njcolledge.net>
* Removed TODO comment, added test for NAPTR record.
Signed-off-by: Nic Colledge <nic@njcolledge.net>
* Run gostaticheck
Run gostaticcheck on the codebase and fix almost all flagged items.
Only keep
* coremain/run.go:192:2: var appVersion is unused (U1000)
* plugin/chaos/setup.go:54:3: the surrounding loop is unconditionally terminated (SA4004)
* plugin/etcd/setup.go:103:3: the surrounding loop is unconditionally terminated (SA4004)
* plugin/pkg/replacer/replacer.go:274:13: argument should be pointer-like to avoid allocations (SA6002)
* plugin/route53/setup.go:124:28: session.New is deprecated: Use NewSession functions to create sessions instead. NewSession has the same functionality as New except an error can be returned when the func is called instead of waiting to receive an error until a request is made. (SA1019)
* test/grpc_test.go:25:69: grpc.WithTimeout is deprecated: use DialContext and context.WithTimeout instead. Will be supported throughout 1.x. (SA1019)
The first one isn't true, as this is set via ldflags. The rest is
minor. The deprecation should be fixed at some point; I'll file some
issues.
Signed-off-by: Miek Gieben <miek@miek.nl>
* Make sure to plug in the plugins
import the plugins, that file that did this was removed, put it in the
reload test as this requires an almost complete coredns server.
Signed-off-by: Miek Gieben <miek@miek.nl>
Log and returns an error when the name rewrite creates a name that is
illegal. Add test in name_test.go to see if an error is returned.
Possible followup could be the only check this if a name-rewrite is
done.
Fixes: #1638
Signed-off-by: Miek Gieben <miek@miek.nl>
* - add support of metadata values for edns0 local variables
* - comments from review.
* - simplify label check. Add UT
* - enhance check for Labels, add UT
- remove IsMetadataSet
* - edns0 variable - if variable is not found just ignore the rewrite.
This was done anyway, but only deep in the functions, just do this
everywhere; allows for shorter code and request.Request allows for
caching as well.
Cleanups, make it more Go like.
* remove unneeded switches
* remove testdir (why was this there??)
* simplify the logic
* remove unneeded variables
* put short functions on a single line
* fix documentation.
* spin off wire funcs in wire.go, make them functions.
Signed-off-by: Miek Gieben <miek@miek.nl>
This revert 17d807f0 and re-adds the metadata plugin as a plugin that
just sets a label to a value function.
Add package documentation on how to use the metadata package. Make it
clear that any caching is up to the Func implemented.
There are now - no in tree users. We could add the request metadata by
default under names that copy request.Request, i.e
request/ip - remote IP
request/port - remote port
Variables.go has been deleted.
Signed-off-by: Miek Gieben <miek@miek.nl>
This fix enables goimports check and fixes several imports format
so that the import sections are prettier, e.g.:
```
import (
- "github.com/miekg/dns"
"regexp"
"strconv"
"strings"
+
+ "github.com/miekg/dns"
)
```
Signed-off-by: Yong Tang <yong.tang.github@outlook.com>
* Rename middleware to plugin
first pass; mostly used 'sed', few spots where I manually changed
text.
This still builds a coredns binary.
* fmt error
* Rename AddMiddleware to AddPlugin
* Readd AddMiddleware to remain backwards compat
