Add server-count support with random selection algorithm

.github/workflows/ci.yaml

@@ -28,7 +28,7 @@ jobs:
       - uses: actions/checkout@v2
       - uses: actions/setup-go@v1
         with:
-          go-version: 1.17
+          go-version: 1.21
       - run: |
           go build -race  ./...
   test:
@@ -38,9 +38,9 @@ jobs:
       - uses: actions/checkout@v2
       - uses: actions/setup-go@v1
         with:
-          go-version: 1.17
+          go-version: 1.21
       - name: Install gotestsum
-        run: go get gotest.tools/gotestsum@v0.4.0
+        run: go install gotest.tools/gotestsum@v0.4.0
       - name: Run tests
         run: |
           eval $(go env)
@@ -50,7 +50,7 @@ jobs:
     name: golangci-lint
     runs-on: ubuntu-latest
     env:
-      GOLANGCI_LINT_CONTAINER: golangci/golangci-lint:v1.23.2
+      GOLANGCI_LINT_CONTAINER: golangci/golangci-lint:v1.59.1
     steps:
       - name: Check out code into the Go module directory
         uses: actions/checkout@v2
@@ -68,7 +68,7 @@ jobs:
       - uses: actions/checkout@v2
       - uses: actions/setup-go@v1
         with:
-          go-version: 1.17
+          go-version: 1.21
       - name: build coredns binary
         run: |
           go build -o coredns/coredns coredns/main.go
@@ -111,7 +111,7 @@ jobs:
       - uses: actions/checkout@v2
       - uses: actions/setup-go@v1
         with:
-          go-version: 1.17
+          go-version: 1.21
       - run: go mod tidy
       - name: Check for changes in go.mod or go.sum
         run: |
@@ -124,9 +124,9 @@ jobs:
       - uses: actions/checkout@v2
       - uses: actions/setup-go@v1
         with:
-          go-version: 1.17
+          go-version: 1.21
       - name: Install go-header
-        run: 'go get github.com/denis-tingajkin/go-header@v0.2.2'
+        run: 'go install github.com/denis-tingajkin/go-header@v0.2.2'
       - name: Run go-header
         run: |
           eval $(go env)

.github/workflows/push.yaml

@@ -18,7 +18,7 @@ jobs:
 
       - uses: actions/setup-go@v1
         with:
-          go-version: 1.17
+          go-version: 1.21
       - name: "Build coredns binary"
         run: |
           go build -o coredns/coredns coredns/main.go

.github/workflows/release.yaml

@@ -46,7 +46,7 @@ jobs:
 
       - uses: actions/setup-go@v1
         with:
-          go-version: 1.17
+          go-version: 1.21
       - name: "Build coredns binary"
         run: |
           go build -o coredns/coredns coredns/main.go

.golangci.yaml

@@ -9,16 +9,15 @@ linters-settings:
     check-type-assertions: false
     check-blank: false
   govet:
-    check-shadowing: true
+    enable:
+      shadow
     settings:
       printf:
         funcs:
           - (github.com/sirupsen/logrus.FieldLogger).Infof
           - (github.com/sirupsen/logrus.FieldLogger).Warnf
           - (github.com/sirupsen/logrus.FieldLogger).Errorf
           - (github.com/sirupsen/logrus.FieldLogger).Fatalf
-  golint:
-    min-confidence: 0.8
   goimports:
     local-prefixes: github.com/networkservicemesh/sdk
   gocyclo:
@@ -31,13 +30,11 @@ linters-settings:
     min-len: 2
     min-occurrences: 2
   depguard:
-    list-type: blacklist
-    include-go-root: false
-    packages:
-      - errors
-    packages-with-error-message:
-      # specify an error message to output when a blacklisted package is used
-      - errors: "Please use \"github.com/pkg/errors\" instead of \"errors\" in go imports"
+    rules:
+      default:
+        deny:
+          - pkg: "errors"
+            desc: "Please use \"github.com/pkg/errors\" instead of \"errors\" in go imports"
   misspell:
     locale: US
   unparam:
@@ -50,78 +47,45 @@ linters-settings:
     for-loops: false
   gocritic:
     enabled-checks:
-      - appendAssign
-      - assignOp
       - appendCombine
-      - argOrder
-      - badCall
-      - badCond
       - boolExprSimplify
       - builtinShadow
-      - captLocal
-      - caseOrder
-      - codegenComment
-      - commentFormatting
       - commentedOutCode
       - commentedOutImport
-      - defaultCaseOrder
-      - deprecatedComment
       - docStub
-      - dupArg
-      - dupBranchBody
-      - dupCase
       - dupImport
-      - dupSubExpr
-      - elseif
       - emptyFallthrough
       - emptyStringTest
       - equalFold
       - evalOrder
-      - exitAfterDefer
-      - flagDeref
-      - flagName
       - hexLiteral
       - hugeParam
-      - ifElseChain
       - importShadow
       - indexAlloc
       - initClause
       - methodExprCall
       - nestingReduce
-      - newDeref
       - nilValReturn
       - octalLiteral
-      - offBy1
       - paramTypeCombine
       - ptrToRefParam
       - rangeExprCopy
       - rangeValCopy
-      - regexpMust
       - regexpPattern
-      - singleCaseSwitch
-      - sloppyLen
       - sloppyReassign
       - stringXbytes
-      - switchTrue
       - typeAssertChain
-      - typeSwitchVar
       - typeUnparen
       - unlabelStmt
       - unnamedResult
       - unnecessaryBlock
-      - underef
-      - unlambda
-      - unslice
-      - valSwap
       - weakCond
-      - wrapperFunc
       - yodaStyleExpr
 linters:
   disable-all: true
   enable:
     # - rowserrcheck
     - bodyclose
-    - deadcode
     - depguard
     - dogsled
     - dupl
@@ -133,24 +97,20 @@ linters:
     - gocyclo
     - gofmt
     - goimports
-    - golint
+    - revive
     - gosec
     - gosimple
     - govet
     - ineffassign
-    - interfacer
     # - lll
     - misspell
     - nakedret
-    - scopelint
     - staticcheck
-    - structcheck
     - stylecheck
     - typecheck
     - unconvert
     - unparam
     - unused
-    - varcheck
     - whitespace
 issues:
   exclude-use-default: false

README.md

@@ -24,6 +24,11 @@ Each incoming DNS query that hits the CoreDNS fanout plugin will be replicated i
   (Cloudflare) will not work.
 
 * `worker-count` is the number of parallel queries per request. By default equals to count of IP list. Use this only for reducing parallel queries per request.
+* `policy` - specifies the policy of DNS server selection mechanism. The default is `sequential`.
+  * `sequential` - select DNS servers one-by-one based on its order
+  * `weighted-random` - select DNS servers randomly based on `weighted-random-server-count` and `weighted-random-load-factor` params.
+* `weighted-random-server-count` is the number of DNS servers to be requested. Equals to the number of specified IPs by default. Used only with the `weighted-random` policy.
+* `weighted-random-load-factor` - the probability of selecting a server. This is specified in the order of the list of IP addresses and takes values between 1 and 100. By default, all servers have an equal probability of 100. Used only with the `weighted-random` policy.
 * `network` is a specific network protocol. Could be `tcp`, `udp`, `tcp-tls`.
 * `except` is a list is a space-separated list of domains to exclude from proxying.
 * `except-file` is the path to file with line-separated list of domains to exclude from proxying.
@@ -110,3 +115,23 @@ If `race` is enable, we will get `NXDOMAIN` result quickly, otherwise we will ge
     }
 }
 ~~~
+
+Sends parallel requests between two randomly selected resolvers. Note, that `127.0.0.1:9007` would be selected more frequently as it has the highest `weighted-random-load-factor`.
+~~~ corefile
+example.org {
+    fanout . 127.0.0.1:9005 127.0.0.1:9006 127.0.0.1:9007 {
+      policy weighted-random
+      weighted-random-server-count 2
+      weighted-random-load-factor 50 70 100
+    }
+}
+~~~
+
+Sends parallel requests between three resolver sequentially (default mode).
+~~~ corefile
+example.org {
+    fanout . 127.0.0.1:9005 127.0.0.1:9006 127.0.0.1:9007 {
+        policy sequential
+    }
+}
+~~~

const.go

@@ -19,14 +19,18 @@ package fanout
 import "time"
 
 const (
-	maxIPCount     = 100
-	maxWorkerCount = 32
-	minWorkerCount = 2
-	maxTimeout     = 2 * time.Second
-	defaultTimeout = 30 * time.Second
-	readTimeout    = 2 * time.Second
-	attemptDelay   = time.Millisecond * 100
-	tcptls         = "tcp-tls"
-	tcp            = "tcp"
-	udp            = "udp"
+	maxIPCount           = 100
+	maxLoadFactor        = 100
+	minLoadFactor        = 1
+	policyWeightedRandom = "weighted-random"
+	policySequential     = "sequential"
+	maxWorkerCount       = 32
+	minWorkerCount       = 2
+	maxTimeout           = 2 * time.Second
+	defaultTimeout       = 30 * time.Second
+	readTimeout          = 2 * time.Second
+	attemptDelay         = time.Millisecond * 100
+	tcptls               = "tcp-tls"
+	tcp                  = "tcp"
+	udp                  = "udp"
 )

coredns/go.mod

@@ -1,39 +1,46 @@
 module github.com/networkservicemesh/fanout/coredns
 
-go 1.17
+go 1.21
 
 require (
-	github.com/coredns/coredns v1.9.1
+	github.com/coredns/coredns v1.11.3
 	github.com/networkservicemesh/fanout v0.0.0-20200313150119-ddef81d89163
 )
 
 require (
 	github.com/apparentlymart/go-cidr v1.1.0 // indirect
 	github.com/beorn7/perks v1.0.1 // indirect
-	github.com/cespare/xxhash/v2 v2.1.2 // indirect
+	github.com/cespare/xxhash/v2 v2.2.0 // indirect
 	github.com/coredns/caddy v1.1.1 // indirect
 	github.com/dnstap/golang-dnstap v0.4.0 // indirect
 	github.com/farsightsec/golang-framestream v0.3.0 // indirect
 	github.com/flynn/go-shlex v0.0.0-20150515145356-3f9db97f8568 // indirect
-	github.com/golang/protobuf v1.5.2 // indirect
+	github.com/go-task/slim-sprig v0.0.0-20230315185526-52ccab3ef572 // indirect
+	github.com/golang/protobuf v1.5.4 // indirect
+	github.com/google/pprof v0.0.0-20230817174616-7a8ec2ada47b // indirect
 	github.com/grpc-ecosystem/grpc-opentracing v0.0.0-20180507213350-8e809c8a8645 // indirect
-	github.com/matttproud/golang_protobuf_extensions v1.0.1 // indirect
-	github.com/miekg/dns v1.1.46 // indirect
+	github.com/matttproud/golang_protobuf_extensions v1.0.4 // indirect
+	github.com/miekg/dns v1.1.61 // indirect
+	github.com/onsi/ginkgo/v2 v2.13.0 // indirect
 	github.com/opentracing/opentracing-go v1.2.0 // indirect
 	github.com/pkg/errors v0.9.1 // indirect
-	github.com/prometheus/client_golang v1.12.1 // indirect
-	github.com/prometheus/client_model v0.2.0 // indirect
-	github.com/prometheus/common v0.32.1 // indirect
-	github.com/prometheus/procfs v0.7.3 // indirect
-	golang.org/x/mod v0.4.2 // indirect
-	golang.org/x/net v0.0.0-20220127200216-cd36cc0744dd // indirect
-	golang.org/x/sys v0.0.0-20220209214540-3681064d5158 // indirect
-	golang.org/x/text v0.3.7 // indirect
-	golang.org/x/tools v0.1.6-0.20210726203631-07bc1bf47fb2 // indirect
-	golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1 // indirect
-	google.golang.org/genproto v0.0.0-20220218161850-94dd64e39d7c // indirect
-	google.golang.org/grpc v1.44.0 // indirect
-	google.golang.org/protobuf v1.27.1 // indirect
+	github.com/prometheus/client_golang v1.19.1 // indirect
+	github.com/prometheus/client_model v0.6.0 // indirect
+	github.com/prometheus/common v0.53.0 // indirect
+	github.com/prometheus/procfs v0.12.0 // indirect
+	github.com/quic-go/quic-go v0.42.0 // indirect
+	go.uber.org/mock v0.4.0 // indirect
+	golang.org/x/crypto v0.24.0 // indirect
+	golang.org/x/exp v0.0.0-20230321023759-10a507213a29 // indirect
+	golang.org/x/mod v0.18.0 // indirect
+	golang.org/x/net v0.26.0 // indirect
+	golang.org/x/sync v0.7.0 // indirect
+	golang.org/x/sys v0.21.0 // indirect
+	golang.org/x/text v0.16.0 // indirect
+	golang.org/x/tools v0.22.0 // indirect
+	google.golang.org/genproto/googleapis/rpc v0.0.0-20240318140521-94a12d6c2237 // indirect
+	google.golang.org/grpc v1.63.2 // indirect
+	google.golang.org/protobuf v1.33.0 // indirect
 )
 
 replace github.com/networkservicemesh/fanout => ../