open-consul/command/connect/envoy/bootstrap_config.go

714 lines
24 KiB
Go
Raw Normal View History

package envoy
import (
"bytes"
"encoding/json"
"fmt"
"net"
"net/url"
"os"
"strings"
"text/template"
"github.com/hashicorp/consul/api"
)
const (
selfAdminName = "self_admin"
)
// BootstrapConfig is the set of keys we care about in a Connect.Proxy.Config
// map. Note that this only includes config keys that affects Envoy bootstrap
// generation. For Envoy config keys that affect runtime xDS behavior see
// agent/xds/config.go.
type BootstrapConfig struct {
// StatsdURL allows simple configuration of the statsd metrics sink. If
// tagging is required, use DogstatsdURL instead. The URL must be in one of
// the following forms:
// - udp://<ip>:<port>
// - $ENV_VAR_NAME in this case the ENV var named will have it's
// value taken and is expected to contain a URL in
// one of the supported forms above.
StatsdURL string `mapstructure:"envoy_statsd_url"`
// DogstatsdURL allows simple configuration of the dogstatsd metrics sink
// which allows tags and Unix domain sockets. The URL must be in one of the
// following forms:
// - udp://<ip>:<port>
// - unix:///full/path/to/unix.sock
// - $ENV_VAR_NAME in this case the ENV var named will have it's
// value taken and is expected to contain a URL in
// one of the supported forms above.
DogstatsdURL string `mapstructure:"envoy_dogstatsd_url"`
// StatsTags is a slice of string values that will be added as tags to
// metrics. They are used to configure
// https://www.envoyproxy.io/docs/envoy/v1.9.0/api-v2/config/metrics/v2/stats.proto#envoy-api-msg-config-metrics-v2-statsconfig
// and add to the basic tags Consul adds by default like the local_cluster
// name. Only exact values are supported here. Full configuration of
// stats_config.stats_tags can be made by overriding envoy_stats_config_json.
StatsTags []string `mapstructure:"envoy_stats_tags"`
// PrometheusBindAddr configures an <ip>:<port> on which the Envoy will listen
// and expose a single /metrics HTTP endpoint for Prometheus to scrape. It
// does this by proxying that URL to the internal admin server's prometheus
// endpoint which allows exposing metrics on the network without the security
// risk of exposing the full admin server API. Any other URL requested will be
// a 404.
//
// Note that as of Envoy 1.9.0, the built in Prometheus endpoint only exports
// counters and gauges but not timing information via histograms. This is
// fixed in 1.10-dev currently in Envoy master. Other changes since 1.9.0 make
// master incompatible with the current release of Consul Connect. This will
// be fixed in a future Consul version as Envoy 1.10 reaches stable release.
PrometheusBindAddr string `mapstructure:"envoy_prometheus_bind_addr"`
// StatsBindAddr configures an <ip>:<port> on which the Envoy will listen
// and expose the /stats HTTP path prefix for any agent to access. It
// does this by proxying that path prefix to the internal admin server
// which allows exposing metrics on the network without the security
// risk of exposing the full admin server API. Any other URL requested will be
// a 404.
StatsBindAddr string `mapstructure:"envoy_stats_bind_addr"`
// ReadyBindAddr configures an <ip>:<port> on which Envoy will listen and
// expose a single /ready HTTP endpoint. This is useful for checking the
// liveness of an Envoy instance when no other listeners are garaunteed to be
// configured, as is the case with ingress gateways.
//
// Note that we do not allow this to be configured via the service
// definition config map currently.
ReadyBindAddr string `mapstructure:"-"`
// OverrideJSONTpl allows replacing the base template used to render the
// bootstrap. This is an "escape hatch" allowing arbitrary control over the
// proxy's configuration but will the most effort to maintain and correctly
// configure the aspects that Connect relies upon to work. It's recommended
// that this only be used if necessary, and that it be based on the default
// template in
// https://github.com/hashicorp/consul/blob/main/command/connect/envoy/bootstrap_tpl.go
// for the correct version of Consul and Envoy being used.
OverrideJSONTpl string `mapstructure:"envoy_bootstrap_json_tpl"`
// StaticClustersJSON is a JSON string containing zero or more Cluster
// definitions. They are appended to the "static_resources.clusters" list. A
// single cluster should be given as a plain object, if more than one is to be
// added, they should be separated by a comma suitable for direct injection
// into a JSON array.
//
// Note that cluster names should be chosen in such a way that they won't
// collide with service names since we use plain service names as cluster
// names in xDS to make metrics population simpler and cluster names mush be
// unique.
//
// This is mostly intended for providing clusters for tracing or metrics
// services.
//
// See https://www.envoyproxy.io/docs/envoy/v1.9.0/api-v2/api/v2/cds.proto.
StaticClustersJSON string `mapstructure:"envoy_extra_static_clusters_json"`
// StaticListenersJSON is a JSON string containing zero or more Listener
// definitions. They are appended to the "static_resources.listeners" list. A
// single listener should be given as a plain object, if more than one is to
// be added, they should be separated by a comma suitable for direct injection
// into a JSON array.
//
// See https://www.envoyproxy.io/docs/envoy/v1.9.0/api-v2/api/v2/lds.proto.
StaticListenersJSON string `mapstructure:"envoy_extra_static_listeners_json"`
// StatsSinksJSON is a JSON string containing zero or more StatsSink
// definititions. They are appended to the `stats_sinks` array at the top
// level of the bootstrap config. A single sink should be given as a plain
// object, if more than one is to be added, they should be separated by a
// comma suitable for direct injection into a JSON array.
//
// See
// https://www.envoyproxy.io/docs/envoy/v1.9.0/api-v2/config/metrics/v2/stats.proto#config-metrics-v2-statssink.
//
// If this is non-empty then it will override anything configured in
// StatsTags.
StatsSinksJSON string `mapstructure:"envoy_extra_stats_sinks_json"`
// StatsConfigJSON is a JSON string containing an object in the right format
// to be rendered as the body of the `stats_config` field at the top level of
// the bootstrap config. It's format may vary based on Envoy version used. See
// https://www.envoyproxy.io/docs/envoy/v1.9.0/api-v2/config/metrics/v2/stats.proto#envoy-api-msg-config-metrics-v2-statsconfig.
//
// If this is non-empty then it will override anything configured in
// StatsdURL or DogstatsdURL.
StatsConfigJSON string `mapstructure:"envoy_stats_config_json"`
// StatsFlushInterval is the time duration between Envoy stats flushes. It is
// in proto3 "duration" string format for example "1.12s" See
// https://developers.google.com/protocol-buffers/docs/proto3#json and
// https://www.envoyproxy.io/docs/envoy/v1.9.0/api-v2/config/bootstrap/v2/bootstrap.proto#bootstrap
StatsFlushInterval string `mapstructure:"envoy_stats_flush_interval"`
// TracingConfigJSON is a JSON string containing an object in the right format
// to be rendered as the body of the `tracing` field at the top level of
// the bootstrap config. It's format may vary based on Envoy version used.
// See https://www.envoyproxy.io/docs/envoy/v1.9.0/api-v2/config/trace/v2/trace.proto.
TracingConfigJSON string `mapstructure:"envoy_tracing_json"`
}
// Template returns the bootstrap template to use as a base.
func (c *BootstrapConfig) Template() string {
if c.OverrideJSONTpl != "" {
return c.OverrideJSONTpl
}
return bootstrapTemplate
}
func (c *BootstrapConfig) GenerateJSON(args *BootstrapTplArgs, omitDeprecatedTags bool) ([]byte, error) {
if err := c.ConfigureArgs(args, omitDeprecatedTags); err != nil {
return nil, err
}
t, err := template.New("bootstrap").Parse(c.Template())
if err != nil {
return nil, err
}
var buf bytes.Buffer
err = t.Execute(&buf, args)
if err != nil {
return nil, err
}
// Pretty print the JSON.
var buf2 bytes.Buffer
if err := json.Indent(&buf2, buf.Bytes(), "", " "); err != nil {
return nil, err
}
return buf2.Bytes(), nil
}
// ConfigureArgs takes the basic template arguments generated from the command
// arguments and environment and modifies them according to the BootstrapConfig.
func (c *BootstrapConfig) ConfigureArgs(args *BootstrapTplArgs, omitDeprecatedTags bool) error {
// Attempt to setup sink(s) from high-level config. Note the args are passed
// by ref and modified in place.
if err := c.generateStatsSinks(args); err != nil {
return err
}
if c.StatsConfigJSON != "" {
// StatsConfig overridden explicitly
args.StatsConfigJSON = c.StatsConfigJSON
} else {
// Attempt to setup tags from high-level config. Note the args are passed by
// ref and modified in place.
stats, err := generateStatsTags(args, c.StatsTags, omitDeprecatedTags)
if err != nil {
return err
}
args.StatsConfigJSON = formatStatsTags(stats)
}
if c.StaticClustersJSON != "" {
args.StaticClustersJSON = c.StaticClustersJSON
}
if c.StaticListenersJSON != "" {
args.StaticListenersJSON = c.StaticListenersJSON
}
// Setup prometheus if needed. This MUST happen after the Static*JSON is set above
if c.PrometheusBindAddr != "" {
if err := c.generateListenerConfig(args, c.PrometheusBindAddr, "envoy_prometheus_metrics", "path", args.PrometheusScrapePath, "/stats/prometheus", args.PrometheusBackendPort); err != nil {
return err
}
}
// Setup /stats proxy listener if needed. This MUST happen after the Static*JSON is set above
if c.StatsBindAddr != "" {
if err := c.generateListenerConfig(args, c.StatsBindAddr, "envoy_metrics", "prefix", "/stats", "/stats", ""); err != nil {
return err
}
}
// Setup /ready proxy listener if needed. This MUST happen after the Static*JSON is set above
if c.ReadyBindAddr != "" {
if err := c.generateListenerConfig(args, c.ReadyBindAddr, "envoy_ready", "path", "/ready", "/ready", ""); err != nil {
return err
}
}
if c.TracingConfigJSON != "" {
args.TracingConfigJSON = c.TracingConfigJSON
}
if c.StatsFlushInterval != "" {
args.StatsFlushInterval = c.StatsFlushInterval
}
return nil
}
func (c *BootstrapConfig) generateStatsSinks(args *BootstrapTplArgs) error {
var stats_sinks []string
if c.StatsdURL != "" {
sinkJSON, err := c.generateStatsSinkJSON(
"envoy.stat_sinks.statsd",
"type.googleapis.com/envoy.config.metrics.v3.StatsdSink",
c.StatsdURL,
)
if err != nil {
return err
}
stats_sinks = append(stats_sinks, sinkJSON)
}
if c.DogstatsdURL != "" {
sinkJSON, err := c.generateStatsSinkJSON(
"envoy.stat_sinks.dog_statsd",
"type.googleapis.com/envoy.config.metrics.v3.DogStatsdSink",
c.DogstatsdURL,
)
if err != nil {
return err
}
stats_sinks = append(stats_sinks, sinkJSON)
}
if c.StatsSinksJSON != "" {
stats_sinks = append(stats_sinks, c.StatsSinksJSON)
}
if len(stats_sinks) > 0 {
args.StatsSinksJSON = "[\n" + strings.Join(stats_sinks, ",\n") + "\n]"
}
return nil
}
func (c *BootstrapConfig) generateStatsSinkJSON(name string, typeName string, addr string) (string, error) {
// Resolve address ENV var
if len(addr) > 2 && addr[0] == '$' {
addr = os.Getenv(addr[1:])
} else {
addr = os.Expand(addr, statsSinkEnvMapping)
}
u, err := url.Parse(addr)
if err != nil {
return "", fmt.Errorf("failed to parse %s sink address %q", name, addr)
}
var addrJSON string
switch u.Scheme {
case "udp":
addrJSON = `
"socket_address": {
"address": "` + u.Hostname() + `",
"port_value": ` + u.Port() + `
}
`
case "unix":
addrJSON = `
"pipe": {
"path": "` + u.Path + `"
}
`
default:
return "", fmt.Errorf("unsupported address protocol %q for %s sink",
u.Scheme, name)
}
return `{
"name": "` + name + `",
"typedConfig": {
"@type": "` + typeName + `",
"address": {
` + addrJSON + `
}
}
}`, nil
}
func statsSinkEnvMapping(s string) string {
allowedStatsSinkEnvVars := map[string]bool{
"HOST_IP": true,
}
if !allowedStatsSinkEnvVars[s] {
// if the specified env var isn't explicitly allowed, unexpand it
return fmt.Sprintf("${%s}", s)
}
return os.Getenv(s)
}
// resourceTagSpecifiers returns patterns used to generate tags from cluster and filter metric names.
func resourceTagSpecifiers(omitDeprecatedTags bool) ([]string, error) {
const (
reSegment = `[^.]+`
)
// For all rules:
// - The outer capture group is removed from the final metric name.
// - The inner capture group is extracted into labels.
rules := [][]string{
// Cluster metrics are prefixed by consul.destination
//
// Cluster metric name format:
// <subset>.<service>.<namespace>.<datacenter>.<internal|external>.<trustdomain>.consul
//
// Examples:
// - cluster.pong.default.dc2.internal.e5b08d03-bfc3-c870-1833-baddb116e648.consul.bind_errors: 0
// - cluster.f8f8f8f8~pong.default.dc2.internal.e5b08d03-bfc3-c870-1833-baddb116e648.consul.bind_errors: 0
// - cluster.v2.pong.default.dc2.internal.e5b08d03-bfc3-c870-1833-baddb116e648.consul.bind_errors: 0
// - cluster.f8f8f8f8~v2.pong.default.dc2.internal.e5b08d03-bfc3-c870-1833-baddb116e648.consul.bind_errors: 0
// - cluster.passthrough~pong.default.dc2.internal.e5b08d03-bfc3-c870-1833-baddb116e648.consul.bind_errors: 0
{"consul.destination.custom_hash",
fmt.Sprintf(`^cluster\.(?:passthrough~)?((?:(%s)~)?(?:%s\.)?%s\.%s\.%s\.%s\.%s\.consul\.)`,
reSegment, reSegment, reSegment, reSegment, reSegment, reSegment, reSegment)},
{"consul.destination.service_subset",
fmt.Sprintf(`^cluster\.(?:passthrough~)?((?:%s~)?(?:(%s)\.)?%s\.%s\.%s\.%s\.%s\.consul\.)`,
reSegment, reSegment, reSegment, reSegment, reSegment, reSegment, reSegment)},
{"consul.destination.service",
fmt.Sprintf(`^cluster\.(?:passthrough~)?((?:%s~)?(?:%s\.)?(%s)\.%s\.%s\.%s\.%s\.consul\.)`,
reSegment, reSegment, reSegment, reSegment, reSegment, reSegment, reSegment)},
{"consul.destination.namespace",
fmt.Sprintf(`^cluster\.(?:passthrough~)?((?:%s~)?(?:%s\.)?%s\.(%s)\.%s\.%s\.%s\.consul\.)`,
reSegment, reSegment, reSegment, reSegment, reSegment, reSegment, reSegment)},
{"consul.destination.datacenter",
fmt.Sprintf(`^cluster\.(?:passthrough~)?((?:%s~)?(?:%s\.)?%s\.%s\.(%s)\.%s\.%s\.consul\.)`,
reSegment, reSegment, reSegment, reSegment, reSegment, reSegment, reSegment)},
{"consul.destination.routing_type",
fmt.Sprintf(`^cluster\.(?:passthrough~)?((?:%s~)?(?:%s\.)?%s\.%s\.%s\.(%s)\.%s\.consul\.)`,
reSegment, reSegment, reSegment, reSegment, reSegment, reSegment, reSegment)},
{"consul.destination.trust_domain",
fmt.Sprintf(`^cluster\.(?:passthrough~)?((?:%s~)?(?:%s\.)?%s\.%s\.%s\.%s\.(%s)\.consul\.)`,
reSegment, reSegment, reSegment, reSegment, reSegment, reSegment, reSegment)},
{"consul.destination.target",
fmt.Sprintf(`^cluster\.(?:passthrough~)?(((?:%s~)?(?:%s\.)?%s\.%s\.%s)\.%s\.%s\.consul\.)`,
reSegment, reSegment, reSegment, reSegment, reSegment, reSegment, reSegment)},
{"consul.destination.full_target",
fmt.Sprintf(`^cluster\.(?:passthrough~)?(((?:%s~)?(?:%s\.)?%s\.%s\.%s\.%s\.%s)\.consul\.)`,
reSegment, reSegment, reSegment, reSegment, reSegment, reSegment, reSegment)},
// Upstream listener metrics are prefixed by consul.upstream
//
// Listener metric name format:
// <tcp|http>.upstream.<service>.<namespace>.<datacenter>
//
// Examples:
// - tcp.upstream.db.dc1.downstream_cx_total: 0
// - http.upstream.web.default.dc1.downstream_cx_total: 0
{"consul.upstream.service",
fmt.Sprintf(`^(?:tcp|http)\.upstream\.((%s)(?:\.%s)?\.%s\.)`,
reSegment, reSegment, reSegment)},
{"consul.upstream.datacenter",
fmt.Sprintf(`^(?:tcp|http)\.upstream\.(%s(?:\.%s)?\.(%s)\.)`,
reSegment, reSegment, reSegment)},
{"consul.upstream.namespace",
fmt.Sprintf(`^(?:tcp|http)\.upstream\.(%s(?:\.(%s))?\.%s\.)`,
reSegment, reSegment, reSegment)},
}
// These tags were deprecated in Consul 1.9.0
// We are leaving them enabled by default for backwards compatibility
if !omitDeprecatedTags {
deprecatedRules := [][]string{
{"consul.custom_hash",
fmt.Sprintf(`^cluster\.((?:(%s)~)?(?:%s\.)?%s\.%s\.%s\.%s\.%s\.consul\.)`,
reSegment, reSegment, reSegment, reSegment, reSegment, reSegment, reSegment)},
{"consul.service_subset",
fmt.Sprintf(`^cluster\.((?:%s~)?(?:(%s)\.)?%s\.%s\.%s\.%s\.%s\.consul\.)`,
reSegment, reSegment, reSegment, reSegment, reSegment, reSegment, reSegment)},
{"consul.service",
fmt.Sprintf(`^cluster\.((?:%s~)?(?:%s\.)?(%s)\.%s\.%s\.%s\.%s\.consul\.)`,
reSegment, reSegment, reSegment, reSegment, reSegment, reSegment, reSegment)},
{"consul.namespace",
fmt.Sprintf(`^cluster\.((?:%s~)?(?:%s\.)?%s\.(%s)\.%s\.%s\.%s\.consul\.)`,
reSegment, reSegment, reSegment, reSegment, reSegment, reSegment, reSegment)},
{"consul.datacenter",
fmt.Sprintf(`^cluster\.((?:%s~)?(?:%s\.)?%s\.%s\.(%s)\.%s\.%s\.consul\.)`,
reSegment, reSegment, reSegment, reSegment, reSegment, reSegment, reSegment)},
{"consul.routing_type",
fmt.Sprintf(`^cluster\.((?:%s~)?(?:%s\.)?%s\.%s\.%s\.(%s)\.%s\.consul\.)`,
reSegment, reSegment, reSegment, reSegment, reSegment, reSegment, reSegment)},
{"consul.trust_domain",
fmt.Sprintf(`^cluster\.((?:%s~)?(?:%s\.)?%s\.%s\.%s\.%s\.(%s)\.consul\.)`,
reSegment, reSegment, reSegment, reSegment, reSegment, reSegment, reSegment)},
{"consul.target",
fmt.Sprintf(`^cluster\.(((?:%s~)?(?:%s\.)?%s\.%s\.%s)\.%s\.%s\.consul\.)`,
reSegment, reSegment, reSegment, reSegment, reSegment, reSegment, reSegment)},
{"consul.full_target",
fmt.Sprintf(`^cluster\.(((?:%s~)?(?:%s\.)?%s\.%s\.%s\.%s\.%s)\.consul\.)`,
reSegment, reSegment, reSegment, reSegment, reSegment, reSegment, reSegment)},
}
rules = append(rules, deprecatedRules...)
}
var tags []string
for _, rule := range rules {
m := map[string]string{
"tag_name": rule[0],
"regex": rule[1],
}
d, err := json.Marshal(m)
if err != nil {
return nil, err
}
tags = append(tags, string(d))
}
return tags, nil
}
func formatStatsTags(tags []string) string {
var output string
if len(tags) > 0 {
// use_all_default_tags is true by default but we'll make it explicit!
output = `{
"stats_tags": [
` + strings.Join(tags, ",\n") + `
],
"use_all_default_tags": true
}`
}
return output
}
func generateStatsTags(args *BootstrapTplArgs, initialTags []string, omitDeprecatedTags bool) ([]string, error) {
var (
// Track tags we are setting explicitly to exclude them from defaults
tagNames = make(map[string]struct{})
tagJSONs []string
)
for _, tag := range initialTags {
parts := strings.SplitN(tag, "=", 2)
// If there is no equals, treat it as a boolean tag and just assign value of
// 1 e.g. "canary" will out put the tag "canary: 1"
v := "1"
if len(parts) == 2 {
v = parts[1]
}
k := strings.ToLower(parts[0])
tagJSON := `{
"tag_name": "` + k + `",
"fixed_value": "` + v + `"
}`
tagJSONs = append(tagJSONs, tagJSON)
tagNames[k] = struct{}{}
}
// Explode listener and cluster portions.
tags, err := resourceTagSpecifiers(omitDeprecatedTags)
if err != nil {
return nil, fmt.Errorf("failed to generate resource-specific envoy tags: %v", err)
}
tagJSONs = append(tagJSONs, tags...)
// Default the namespace here since it is also done for cluster SNI
ns := args.Namespace
if ns == "" {
ns = api.IntentionDefaultNamespace
}
// Add some default tags if not already overridden. Note this is a slice not a
// map since we need ordering to be deterministic.
defaults := []struct {
name string
val string
}{
// local_cluster is for backwards compatibility. We originally choose this
// name as it matched a few other Envoy metrics examples given in docs but
// it's a little confusing in context of setting up metrics dashboards.
{
name: "local_cluster",
val: args.ProxyCluster,
},
{
name: "consul.source.service",
val: args.ProxySourceService,
},
{
name: "consul.source.namespace",
val: ns,
},
{
name: "consul.source.datacenter",
val: args.Datacenter,
},
}
for _, kv := range defaults {
if kv.val == "" {
// Skip stuff we just didn't have data for.
continue
}
if _, ok := tagNames[kv.name]; ok {
// Skip anything already set explicitly.
continue
}
tagJSON := `{
"tag_name": "` + kv.name + `",
"fixed_value": "` + kv.val + `"
}`
tagJSONs = append(tagJSONs, tagJSON)
}
return tagJSONs, nil
}
func (c *BootstrapConfig) generateListenerConfig(args *BootstrapTplArgs, bindAddr, name, matchType, matchValue, prefixRewrite, prometheusBackendPort string) error {
host, port, err := net.SplitHostPort(bindAddr)
if err != nil {
return fmt.Errorf("invalid %s bind address: %s", name, err)
}
// If prometheusBackendPort is set (not empty string), create
// "prometheus_backend" cluster with the prometheusBackendPort that the
// listener will point to, rather than the "self_admin" cluster. This is for
// the merged metrics feature in consul-k8s, so the
// envoy_prometheus_bind_addr listener will point to the merged Envoy and
// service metrics endpoint rather than the Envoy admin endpoint for
// metrics. This cluster will only be created once since it's only created
// when prometheusBackendPort is set, and prometheusBackendPort is only set
// when calling this function if c.PrometheusBindAddr is set.
clusterPort := args.AdminBindPort
clusterName := selfAdminName
if prometheusBackendPort != "" {
clusterPort = prometheusBackendPort
clusterName = "prometheus_backend"
}
clusterJSON := `{
"name": "` + clusterName + `",
"ignore_health_on_host_removal": false,
"connect_timeout": "5s",
"type": "STATIC",
"http_protocol_options": {},
"loadAssignment": {
"clusterName": "` + clusterName + `",
"endpoints": [
{
"lbEndpoints": [
{
"endpoint": {
"address": {
"socket_address": {
"address": "127.0.0.1",
"port_value": ` + clusterPort + `
}
}
}
}
]
}
]
}
}`
listenerJSON := `{
"name": "` + name + `_listener",
"address": {
"socket_address": {
"address": "` + host + `",
"port_value": ` + port + `
}
},
"filter_chains": [
{
"filters": [
{
"name": "envoy.filters.network.http_connection_manager",
"typedConfig": {
"@type": "type.googleapis.com/envoy.extensions.filters.network.http_connection_manager.v3.HttpConnectionManager",
"stat_prefix": "` + name + `",
"codec_type": "HTTP1",
"route_config": {
"name": "self_admin_route",
"virtual_hosts": [
{
"name": "self_admin",
"domains": [
"*"
],
"routes": [
{
"match": {
"` + matchType + `": "` + matchValue + `"
},
"route": {
"cluster": "` + clusterName + `",
"prefix_rewrite": "` + prefixRewrite + `"
}
},
{
"match": {
"prefix": "/"
},
"direct_response": {
"status": 404
}
}
]
}
]
},
"http_filters": [
{
"name": "envoy.filters.http.router"
}
]
}
}
]
}
]
}`
// Make sure we do not append the same cluster multiple times, as that will
// cause envoy startup to fail.
selfAdminClusterExists, err := containsSelfAdminCluster(args.StaticClustersJSON)
if err != nil {
return err
}
if args.StaticClustersJSON == "" {
args.StaticClustersJSON = clusterJSON
} else if !selfAdminClusterExists {
args.StaticClustersJSON += ",\n" + clusterJSON
}
if args.StaticListenersJSON != "" {
listenerJSON = ",\n" + listenerJSON
}
args.StaticListenersJSON += listenerJSON
return nil
}
func containsSelfAdminCluster(clustersJSON string) (bool, error) {
clusterNames := []struct {
Name string
}{}
// StaticClustersJSON is defined as a comma-separated list of clusters, so we
// need to wrap it in JSON array brackets
err := json.Unmarshal([]byte("["+clustersJSON+"]"), &clusterNames)
if err != nil {
return false, fmt.Errorf("failed to parse static clusters: %s", err)
}
for _, cluster := range clusterNames {
if cluster.Name == selfAdminName {
return true, nil
}
}
return false, nil
}