llb: add extrahost support

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>

client/llb/exec.go

@@ -2,6 +2,7 @@ package llb
 
 import (
 	_ "crypto/sha256"
+	"net"
 	"sort"
 
 	"github.com/moby/buildkit/solver/pb"
@@ -10,11 +11,12 @@ import (
 )
 
 type Meta struct {
-	Args     []string
-	Env      EnvList
-	Cwd      string
-	User     string
-	ProxyEnv *ProxyEnv
+	Args       []string
+	Env        EnvList
+	Cwd        string
+	User       string
+	ProxyEnv   *ProxyEnv
+	ExtraHosts []HostIP
 }
 
 func NewExecOp(root Output, meta Meta, readOnly bool, c Constraints) *ExecOp {
@@ -127,13 +129,22 @@ func (e *ExecOp) Marshal(c *Constraints) (digest.Digest, []byte, *pb.OpMetadata,
 		return e.mounts[i].target < e.mounts[j].target
 	})
 
+	meta := &pb.Meta{
+		Args: e.meta.Args,
+		Env:  e.meta.Env.ToArray(),
+		Cwd:  e.meta.Cwd,
+		User: e.meta.User,
+	}
+	if len(e.meta.ExtraHosts) > 0 {
+		hosts := make([]*pb.HostIP, len(e.meta.ExtraHosts))
+		for i, h := range e.meta.ExtraHosts {
+			hosts[i] = &pb.HostIP{Host: h.Host, IP: h.IP.String()}
+		}
+		meta.ExtraHosts = hosts
+	}
+
 	peo := &pb.ExecOp{
-		Meta: &pb.Meta{
-			Args: e.meta.Args,
-			Env:  e.meta.Env.ToArray(),
-			Cwd:  e.meta.Cwd,
-			User: e.meta.User,
-		},
+		Meta: meta,
 	}
 
 	if p := e.meta.ProxyEnv; p != nil {
@@ -386,6 +397,12 @@ func Dirf(str string, v ...interface{}) RunOption {
 	})
 }
 
+func AddExtraHost(host string, ip net.IP) RunOption {
+	return runOptionFunc(func(ei *ExecInfo) {
+		ei.State = ei.State.AddExtraHost(host, ip)
+	})
+}
+
 func Reset(s State) RunOption {
 	return runOptionFunc(func(ei *ExecInfo) {
 		ei.State = ei.State.Reset(s)

client/llb/meta.go

@@ -2,6 +2,7 @@ package llb
 
 import (
 	"fmt"
+	"net"
 	"path"
 
 	"github.com/containerd/containerd/platforms"
@@ -12,11 +13,12 @@ import (
 type contextKeyT string
 
 var (
-	keyArgs     = contextKeyT("llb.exec.args")
-	keyDir      = contextKeyT("llb.exec.dir")
-	keyEnv      = contextKeyT("llb.exec.env")
-	keyUser     = contextKeyT("llb.exec.user")
-	keyPlatform = contextKeyT("llb.platform")
+	keyArgs      = contextKeyT("llb.exec.args")
+	keyDir       = contextKeyT("llb.exec.dir")
+	keyEnv       = contextKeyT("llb.exec.env")
+	keyUser      = contextKeyT("llb.exec.user")
+	keyExtraHost = contextKeyT("llb.exec.extrahost")
+	keyPlatform  = contextKeyT("llb.platform")
 )
 
 func addEnv(key, value string) StateOption {
@@ -124,6 +126,25 @@ func getPlatform(s State) *specs.Platform {
 	return nil
 }
 
+func extraHost(host string, ip net.IP) StateOption {
+	return func(s State) State {
+		return s.WithValue(keyExtraHost, append(getExtraHosts(s), HostIP{Host: host, IP: ip}))
+	}
+}
+
+func getExtraHosts(s State) []HostIP {
+	v := s.Value(keyExtraHost)
+	if v != nil {
+		return v.([]HostIP)
+	}
+	return nil
+}
+
+type HostIP struct {
+	Host string
+	IP   net.IP
+}
+
 type EnvList []KeyValue
 
 type KeyValue struct {

client/llb/state.go

@@ -3,6 +3,7 @@ package llb
 import (
 	"context"
 	"fmt"
+	"net"
 
 	"github.com/containerd/containerd/platforms"
 	"github.com/moby/buildkit/identity"
@@ -181,11 +182,12 @@ func (s State) Run(ro ...RunOption) ExecState {
 		o.SetRunOption(ei)
 	}
 	meta := Meta{
-		Args:     getArgs(ei.State),
-		Cwd:      getDir(ei.State),
-		Env:      getEnv(ei.State),
-		User:     getUser(ei.State),
-		ProxyEnv: ei.ProxyEnv,
+		Args:       getArgs(ei.State),
+		Cwd:        getDir(ei.State),
+		Env:        getEnv(ei.State),
+		User:       getUser(ei.State),
+		ProxyEnv:   ei.ProxyEnv,
+		ExtraHosts: getExtraHosts(ei.State),
 	}
 
 	exec := NewExecOp(s.Output(), meta, ei.ReadonlyRootFS, ei.Constraints)
@@ -254,6 +256,10 @@ func (s State) With(so ...StateOption) State {
 	return s
 }
 
+func (s State) AddExtraHost(host string, ip net.IP) State {
+	return extraHost(host, ip)(s)
+}
+
 type output struct {
 	vertex   Vertex
 	getIndex func() (pb.OutputIndex, error)