coredns/plugin/grpc/setup.go
2022-07-10 11:06:33 -07:00

147 lines
2.8 KiB
Go

package grpc
import (
"crypto/tls"
"fmt"
"github.com/coredns/caddy"
"github.com/coredns/coredns/core/dnsserver"
"github.com/coredns/coredns/plugin"
"github.com/coredns/coredns/plugin/pkg/parse"
pkgtls "github.com/coredns/coredns/plugin/pkg/tls"
)
func init() { plugin.Register("grpc", setup) }
func setup(c *caddy.Controller) error {
g, err := parseGRPC(c)
if err != nil {
return plugin.Error("grpc", err)
}
if g.len() > max {
return plugin.Error("grpc", fmt.Errorf("more than %d TOs configured: %d", max, g.len()))
}
dnsserver.GetConfig(c).AddPlugin(func(next plugin.Handler) plugin.Handler {
g.Next = next // Set the Next field, so the plugin chaining works.
return g
})
return nil
}
func parseGRPC(c *caddy.Controller) (*GRPC, error) {
var (
g *GRPC
err error
i int
)
for c.Next() {
if i > 0 {
return nil, plugin.ErrOnce
}
i++
g, err = parseStanza(c)
if err != nil {
return nil, err
}
}
return g, nil
}
func parseStanza(c *caddy.Controller) (*GRPC, error) {
g := newGRPC()
if !c.Args(&g.from) {
return g, c.ArgErr()
}
normalized := plugin.Host(g.from).NormalizeExact()
if len(normalized) == 0 {
return g, fmt.Errorf("unable to normalize '%s'", g.from)
}
g.from = normalized[0] // only the first is used.
to := c.RemainingArgs()
if len(to) == 0 {
return g, c.ArgErr()
}
toHosts, err := parse.HostPortOrFile(to...)
if err != nil {
return g, err
}
for c.NextBlock() {
if err := parseBlock(c, g); err != nil {
return g, err
}
}
if g.tlsServerName != "" {
if g.tlsConfig == nil {
g.tlsConfig = new(tls.Config)
}
g.tlsConfig.ServerName = g.tlsServerName
}
for _, host := range toHosts {
pr, err := newProxy(host, g.tlsConfig)
if err != nil {
return nil, err
}
g.proxies = append(g.proxies, pr)
}
return g, nil
}
func parseBlock(c *caddy.Controller, g *GRPC) error {
switch c.Val() {
case "except":
ignore := c.RemainingArgs()
if len(ignore) == 0 {
return c.ArgErr()
}
for i := 0; i < len(ignore); i++ {
g.ignored = append(g.ignored, plugin.Host(ignore[i]).NormalizeExact()...)
}
case "tls":
args := c.RemainingArgs()
if len(args) > 3 {
return c.ArgErr()
}
tlsConfig, err := pkgtls.NewTLSConfigFromArgs(args...)
if err != nil {
return err
}
g.tlsConfig = tlsConfig
case "tls_servername":
if !c.NextArg() {
return c.ArgErr()
}
g.tlsServerName = c.Val()
case "policy":
if !c.NextArg() {
return c.ArgErr()
}
switch x := c.Val(); x {
case "random":
g.p = &random{}
case "round_robin":
g.p = &roundRobin{}
case "sequential":
g.p = &sequential{}
default:
return c.Errf("unknown policy '%s'", x)
}
default:
if c.Val() != "}" {
return c.Errf("unknown property '%s'", c.Val())
}
}
return nil
}
const max = 15 // Maximum number of upstreams.