fix(*) remove circular dependency on the Istio submodule (#2742)

The Istio submodule imports Kuma config definitions, and Kuma calls
functions from the Istio submodule. Break the circular dependency by
moving the config definitions into the Istio submodule, even though
they more properly belong in Kuma itself.

This makes it possible to run `go mod tidy` in the Istio submodule.

This fixes #2087.

Signed-off-by: James Peach <james.peach@konghq.com>

pkg/transparentproxy/config/config.go

@@ -1,18 +1,10 @@
 package config
 
-type TransparentProxyConfig struct {
-	DryRun                 bool
-	Verbose                bool
-	RedirectPortOutBound   string
-	RedirectInBound        bool
-	RedirectPortInBound    string
-	RedirectPortInBoundV6  string
-	ExcludeInboundPorts    string
-	ExcludeOutboundPorts   string
-	UID                    string
-	GID                    string
-	RedirectDNS            bool
-	RedirectAllDNSTraffic  bool
-	AgentDNSListenerPort   string
-	DNSUpstreamTargetChain string
-}
+import "github.com/kumahq/kuma/pkg/transparentproxy/istio"
+
+// TransparentProxyConfig defines the configuration for all transparent
+// proxy configurations, not just the Istio one.
+//
+// We alias the types in reverse here to avoid an import loop (the Istio
+// submodule depending on Kuma for the config type).
+type TransparentProxyConfig = istio.TransparentProxyConfig

pkg/transparentproxy/istio/config.go

@@ -0,0 +1,18 @@
+package istio
+
+type TransparentProxyConfig struct {
+	DryRun                 bool
+	Verbose                bool
+	RedirectPortOutBound   string
+	RedirectInBound        bool
+	RedirectPortInBound    string
+	RedirectPortInBoundV6  string
+	ExcludeInboundPorts    string
+	ExcludeOutboundPorts   string
+	UID                    string
+	GID                    string
+	RedirectDNS            bool
+	RedirectAllDNSTraffic  bool
+	AgentDNSListenerPort   string
+	DNSUpstreamTargetChain string
+}

pkg/transparentproxy/istio/go.mod

@@ -3,9 +3,11 @@ module github.com/kumahq/kuma/pkg/transparentproxy/istio
 go 1.16
 
 require (
+	github.com/miekg/dns v1.0.14
 	github.com/pkg/errors v0.9.1
-	github.com/spf13/cobra v1.2.1 // indirect
+	github.com/spf13/cobra v1.2.1
 	github.com/spf13/viper v1.8.1
-	// fetched with go get istio.io/istio/tools/istio-iptables@1.7.8
-	istio.io/istio v0.0.0-20210223230603-30e54dcb8a1c
+	golang.org/x/sys v0.0.0-20210510120138-977fb7262007
+	gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15 // indirect
+	istio.io/pkg v0.0.0-20201202160453-b7f8c8c88ca3
 )