presubmit: check import path ordering (#3636)

Add a test for this as well as it's annoying to point out in every code
review.
Fix all the import paths that are flagged by this new test.

Fixes: #3634

Signed-off-by: Miek Gieben <miek@miek.nl>

plugin/cache/prefech_test.go

@@ -8,8 +8,8 @@ import (
 
 	"github.com/coredns/coredns/plugin"
 	"github.com/coredns/coredns/plugin/pkg/dnstest"
-
 	"github.com/coredns/coredns/plugin/test"
+
 	"github.com/miekg/dns"
 )
 

plugin/dnssec/dnskey.go

@@ -9,8 +9,8 @@ import (
 	"time"
 
 	"github.com/coredns/coredns/request"
-	"github.com/miekg/dns"
 
+	"github.com/miekg/dns"
 	"golang.org/x/crypto/ed25519"
 )
 

plugin/etcd/etcd.go

@@ -12,9 +12,9 @@ import (
 	"github.com/coredns/coredns/plugin"
 	"github.com/coredns/coredns/plugin/etcd/msg"
 	"github.com/coredns/coredns/plugin/pkg/fall"
+	"github.com/coredns/coredns/plugin/pkg/upstream"
 	"github.com/coredns/coredns/request"
 
-	"github.com/coredns/coredns/plugin/pkg/upstream"
 	"github.com/miekg/dns"
 	etcdcv3 "go.etcd.io/etcd/clientv3"
 	"go.etcd.io/etcd/mvcc/mvccpb"

plugin/kubernetes/ns_test.go

@@ -5,8 +5,8 @@ import (
 	"testing"
 
 	"github.com/coredns/coredns/plugin/kubernetes/object"
-	"github.com/miekg/dns"
 
+	"github.com/miekg/dns"
 	api "k8s.io/api/core/v1"
 )
 

plugin/kubernetes/setup.go

@@ -19,18 +19,11 @@ import (
 	"github.com/caddyserver/caddy"
 	"github.com/miekg/dns"
 	meta "k8s.io/apimachinery/pkg/apis/meta/v1"
-
-	// Pull this in setting klog's output to stdout
-	"k8s.io/klog"
-
-	// Excluding azure because it is failing to compile
-	// pull this in here, because we want it excluded if plugin.cfg doesn't have k8s
-	_ "k8s.io/client-go/plugin/pkg/client/auth/gcp"
-	// pull this in here, because we want it excluded if plugin.cfg doesn't have k8s
-	_ "k8s.io/client-go/plugin/pkg/client/auth/oidc"
-	// pull this in here, because we want it excluded if plugin.cfg doesn't have k8s
-	_ "k8s.io/client-go/plugin/pkg/client/auth/openstack"
+	_ "k8s.io/client-go/plugin/pkg/client/auth/gcp"       // pull this in here, because we want it excluded if plugin.cfg doesn't have k8s
+	_ "k8s.io/client-go/plugin/pkg/client/auth/oidc"      // pull this in here, because we want it excluded if plugin.cfg doesn't have k8s
+	_ "k8s.io/client-go/plugin/pkg/client/auth/openstack" // pull this in here, because we want it excluded if plugin.cfg doesn't have k8s
 	"k8s.io/client-go/tools/clientcmd"
+	"k8s.io/klog"
 )
 
 var log = clog.NewWithPlugin("kubernetes")

plugin/pkg/upstream/upstream.go

@@ -5,11 +5,11 @@ import (
 	"context"
 	"fmt"
 
-	"github.com/miekg/dns"
-
 	"github.com/coredns/coredns/core/dnsserver"
 	"github.com/coredns/coredns/plugin/pkg/nonwriter"
 	"github.com/coredns/coredns/request"
+
+	"github.com/miekg/dns"
 )
 
 // Upstream is used to resolve CNAME or other external targets via CoreDNS itself.

plugin/test/scrape.go

@@ -30,9 +30,8 @@ import (
 	"strconv"
 
 	"github.com/matttproud/golang_protobuf_extensions/pbutil"
-	"github.com/prometheus/common/expfmt"
-
 	dto "github.com/prometheus/client_model/go"
+	"github.com/prometheus/common/expfmt"
 )
 
 type (

plugin/trace/trace.go

@@ -11,16 +11,14 @@ import (
 	"github.com/coredns/coredns/plugin/metrics"
 	"github.com/coredns/coredns/plugin/pkg/dnstest"
 	"github.com/coredns/coredns/plugin/pkg/rcode"
-	"gopkg.in/DataDog/dd-trace-go.v1/ddtrace/opentracer"
-	"gopkg.in/DataDog/dd-trace-go.v1/ddtrace/tracer"
-
-	// Plugin the trace package.
-	_ "github.com/coredns/coredns/plugin/pkg/trace"
+	_ "github.com/coredns/coredns/plugin/pkg/trace" // Plugin the trace package.
 	"github.com/coredns/coredns/request"
 
 	"github.com/miekg/dns"
 	ot "github.com/opentracing/opentracing-go"
 	zipkin "github.com/openzipkin-contrib/zipkin-go-opentracing"
+	"gopkg.in/DataDog/dd-trace-go.v1/ddtrace/opentracer"
+	"gopkg.in/DataDog/dd-trace-go.v1/ddtrace/tracer"
 )
 
 const (