Initial implementation of ForwardCRD plugin (#4512)
* Add forwardcrd plugin README.md Co-authored-by: Aidan Obley <aobley@vmware.com> Signed-off-by: Christian Ang <angc@vmware.com> * Create forwardcrd plugin - Place forwardcrd before forward plugin in plugin list. This will avoid forward from preventing the forwardcrd plugin from handling any queries in the case of having a default upstream forwarder in a server block (as is the case in the default kubernetes Corefile). Co-authored-by: Aidan Obley <aobley@vmware.com> Signed-off-by: Christian Ang <angc@vmware.com> * Add Forward CRD Signed-off-by: Christian Ang <angc@vmware.com> * Add NewWithConfig to forward plugin - allows external packages to instanciate forward plugins Co-authored-by: Aidan Obley <aobley@vmware.com> Signed-off-by: Christian Ang <angc@vmware.com> * ForwardCRD plugin handles requests for Forward CRs - add a Kubernetes controller that can read Forward CRs - instances of the forward plugin are created based on Forward CRs from the Kubernetes controller - DNS requests are handled by calling matching Forward plugin instances based on zone name - Defaults to the kube-system namespace to align with Corefile RBAC Signed-off-by: Christian Ang <angc@vmware.com> Use klog v2 in forwardcrd plugin * Refactor forward setup to use NewWithConfig Co-authored-by: Christian Ang <angc@vmware.com> Signed-off-by: Edwin Xie <exie@vmware.com> * Use ParseInt instead of Atoi - to ensure that the bitsize is 32 for later casting to uint32 Signed-off-by: Christian Ang <angc@vmware.com> * Add @christianang to CODEOWNERS for forwardcrd Signed-off-by: Christian Ang <angc@vmware.com> Co-authored-by: Edwin Xie <exie@vmware.com>
This commit is contained in:
Christian Ang
GitHub
parent
6953ab2b4f
commit
2e6953c7db
22 changed files with 2471 additions and 91 deletions
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@ -1,8 +1,6 @@
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package forward
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import (
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"crypto/tls"
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"errors"
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"fmt"
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"strconv"
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"time"
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@ -11,9 +9,7 @@ import (
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"github.com/coredns/coredns/core/dnsserver"
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"github.com/coredns/coredns/plugin"
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"github.com/coredns/coredns/plugin/dnstap"
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"github.com/coredns/coredns/plugin/pkg/parse"
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pkgtls "github.com/coredns/coredns/plugin/pkg/tls"
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"github.com/coredns/coredns/plugin/pkg/transport"
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)
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func init() { plugin.Register("forward", setup) }
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@ -87,90 +83,46 @@ func parseForward(c *caddy.Controller) (*Forward, error) {
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}
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func parseStanza(c *caddy.Controller) (*Forward, error) {
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f := New()
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cfg := ForwardConfig{}
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if !c.Args(&f.from) {
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return f, c.ArgErr()
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}
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origFrom := f.from
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zones := plugin.Host(f.from).NormalizeExact()
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f.from = zones[0] // there can only be one here, won't work with non-octet reverse
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if len(zones) > 1 {
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log.Warningf("Unsupported CIDR notation: '%s' expands to multiple zones. Using only '%s'.", origFrom, f.from)
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if !c.Args(&cfg.From) {
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return nil, c.ArgErr()
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}
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to := c.RemainingArgs()
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if len(to) == 0 {
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return f, c.ArgErr()
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}
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toHosts, err := parse.HostPortOrFile(to...)
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if err != nil {
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return f, err
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}
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transports := make([]string, len(toHosts))
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allowedTrans := map[string]bool{"dns": true, "tls": true}
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for i, host := range toHosts {
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trans, h := parse.Transport(host)
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if !allowedTrans[trans] {
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return f, fmt.Errorf("'%s' is not supported as a destination protocol in forward: %s", trans, host)
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}
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p := NewProxy(h, trans)
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f.proxies = append(f.proxies, p)
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transports[i] = trans
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cfg.To = c.RemainingArgs()
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if len(cfg.To) == 0 {
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return nil, c.ArgErr()
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}
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for c.NextBlock() {
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if err := parseBlock(c, f); err != nil {
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return f, err
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if err := parseBlock(c, &cfg); err != nil {
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return nil, err
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}
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}
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if f.tlsServerName != "" {
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f.tlsConfig.ServerName = f.tlsServerName
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}
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// Initialize ClientSessionCache in tls.Config. This may speed up a TLS handshake
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// in upcoming connections to the same TLS server.
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f.tlsConfig.ClientSessionCache = tls.NewLRUClientSessionCache(len(f.proxies))
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for i := range f.proxies {
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// Only set this for proxies that need it.
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if transports[i] == transport.TLS {
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f.proxies[i].SetTLSConfig(f.tlsConfig)
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}
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f.proxies[i].SetExpire(f.expire)
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f.proxies[i].health.SetRecursionDesired(f.opts.hcRecursionDesired)
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}
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return f, nil
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return NewWithConfig(cfg)
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}
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func parseBlock(c *caddy.Controller, f *Forward) error {
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func parseBlock(c *caddy.Controller, cfg *ForwardConfig) error {
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switch c.Val() {
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case "except":
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ignore := c.RemainingArgs()
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if len(ignore) == 0 {
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cfg.Except = c.RemainingArgs()
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if len(cfg.Except) == 0 {
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return c.ArgErr()
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}
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for i := 0; i < len(ignore); i++ {
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f.ignored = append(f.ignored, plugin.Host(ignore[i]).NormalizeExact()...)
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}
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case "max_fails":
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if !c.NextArg() {
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return c.ArgErr()
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}
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n, err := strconv.Atoi(c.Val())
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n, err := strconv.ParseInt(c.Val(), 10, 32)
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if err != nil {
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return err
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}
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if n < 0 {
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return fmt.Errorf("max_fails can't be negative: %d", n)
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}
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f.maxfails = uint32(n)
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maxFails := uint32(n)
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cfg.MaxFails = &maxFails
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case "health_check":
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if !c.NextArg() {
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return c.ArgErr()
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@ -179,15 +131,12 @@ func parseBlock(c *caddy.Controller, f *Forward) error {
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if err != nil {
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return err
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}
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if dur < 0 {
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return fmt.Errorf("health_check can't be negative: %d", dur)
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}
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f.hcInterval = dur
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cfg.HealthCheck = &dur
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for c.NextArg() {
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switch hcOpts := c.Val(); hcOpts {
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case "no_rec":
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f.opts.hcRecursionDesired = false
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cfg.HealthCheckNoRec = true
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default:
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return fmt.Errorf("health_check: unknown option %s", hcOpts)
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}
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@ -197,12 +146,12 @@ func parseBlock(c *caddy.Controller, f *Forward) error {
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if c.NextArg() {
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return c.ArgErr()
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}
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f.opts.forceTCP = true
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cfg.ForceTCP = true
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case "prefer_udp":
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if c.NextArg() {
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return c.ArgErr()
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}
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f.opts.preferUDP = true
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cfg.PreferUDP = true
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case "tls":
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args := c.RemainingArgs()
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if len(args) > 3 {
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@ -213,12 +162,12 @@ func parseBlock(c *caddy.Controller, f *Forward) error {
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if err != nil {
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return err
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}
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f.tlsConfig = tlsConfig
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cfg.TLSConfig = tlsConfig
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case "tls_servername":
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if !c.NextArg() {
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return c.ArgErr()
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}
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f.tlsServerName = c.Val()
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cfg.TLSServerName = c.Val()
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case "expire":
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if !c.NextArg() {
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return c.ArgErr()
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@ -227,24 +176,12 @@ func parseBlock(c *caddy.Controller, f *Forward) error {
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if err != nil {
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return err
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}
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if dur < 0 {
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return fmt.Errorf("expire can't be negative: %s", dur)
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}
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f.expire = dur
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cfg.Expire = &dur
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case "policy":
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if !c.NextArg() {
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return c.ArgErr()
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}
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switch x := c.Val(); x {
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case "random":
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f.p = &random{}
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case "round_robin":
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f.p = &roundRobin{}
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case "sequential":
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f.p = &sequential{}
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default:
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return c.Errf("unknown policy '%s'", x)
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}
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cfg.Policy = c.Val()
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case "max_concurrent":
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if !c.NextArg() {
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return c.ArgErr()
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@ -253,11 +190,8 @@ func parseBlock(c *caddy.Controller, f *Forward) error {
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if err != nil {
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return err
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}
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if n < 0 {
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return fmt.Errorf("max_concurrent can't be negative: %d", n)
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}
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f.ErrLimitExceeded = errors.New("concurrent queries exceeded maximum " + c.Val())
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f.maxConcurrent = int64(n)
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maxConcurrent := int64(n)
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cfg.MaxConcurrent = &maxConcurrent
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default:
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return c.Errf("unknown property '%s'", c.Val())
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