consul/agent/config/runtime.go

739 lines
26 KiB
Go

package config
import (
"crypto/tls"
"fmt"
"net"
"reflect"
"strings"
"time"
"github.com/hashicorp/consul/agent/structs"
"github.com/hashicorp/consul/tlsutil"
"github.com/hashicorp/consul/types"
"golang.org/x/time/rate"
)
// RuntimeConfig specifies the configuration the consul agent actually
// uses. Is is derived from one or more Config structures which can come
// from files, flags and/or environment variables.
type RuntimeConfig struct {
// non-user configurable values
AEInterval time.Duration
// ACLDisabledTTL is used by clients to determine how long they will
// wait to check again with the servers if they discover ACLs are not
// enabled. (not user configurable)
//
// hcl: acl_disabled_ttl = "duration"
ACLDisabledTTL time.Duration
CheckDeregisterIntervalMin time.Duration
CheckReapInterval time.Duration
SegmentLimit int
SegmentNameLimit int
SyncCoordinateRateTarget float64
SyncCoordinateIntervalMin time.Duration
Revision string
Version string
VersionPrerelease string
// consul config
ConsulCoordinateUpdateMaxBatches int
ConsulCoordinateUpdateBatchSize int
ConsulCoordinateUpdatePeriod time.Duration
ConsulRaftElectionTimeout time.Duration
ConsulRaftHeartbeatTimeout time.Duration
ConsulRaftLeaderLeaseTimeout time.Duration
ConsulSerfLANGossipInterval time.Duration
ConsulSerfLANProbeInterval time.Duration
ConsulSerfLANProbeTimeout time.Duration
ConsulSerfLANSuspicionMult int
ConsulSerfWANGossipInterval time.Duration
ConsulSerfWANProbeInterval time.Duration
ConsulSerfWANProbeTimeout time.Duration
ConsulSerfWANSuspicionMult int
ConsulServerHealthInterval time.Duration
// ACLAgentMasterToken is a special token that has full read and write
// privileges for this agent, and can be used to call agent endpoints
// when no servers are available.
//
// hcl: acl_agent_master_token = string
ACLAgentMasterToken string
// ACLAgentToken is the default token used to make requests for the agent
// itself, such as for registering itself with the catalog. If not
// configured, the 'acl_token' will be used.
//
// hcl: acl_agent_token = string
ACLAgentToken string
// ACLDatacenter is the central datacenter that holds authoritative
// ACL records. This must be the same for the entire cluster.
// If this is not set, ACLs are not enabled. Off by default.
//
// hcl: acl_datacenter = string
ACLDatacenter string
// ACLDefaultPolicy is used to control the ACL interaction when
// there is no defined policy. This can be "allow" which means
// ACLs are used to black-list, or "deny" which means ACLs are
// white-lists.
//
// hcl: acl_default_policy = ("allow"|"deny")
ACLDefaultPolicy string
// ACLDownPolicy is used to control the ACL interaction when we cannot
// reach the ACLDatacenter and the token is not in the cache.
// There are two modes:
// * allow - Allow all requests
// * deny - Deny all requests
// * extend-cache - Ignore the cache expiration, and allow cached
// ACL's to be used to service requests. This
// is the default. If the ACL is not in the cache,
// this acts like deny.
//
// hcl: acl_down_policy = ("allow"|"deny"|"extend-cache")
ACLDownPolicy string
// ACLEnforceVersion8 is used to gate a set of ACL policy features that
// are opt-in prior to Consul 0.8 and opt-out in Consul 0.8 and later.
//
// hcl: acl_enforce_version_8 = (true|false)
ACLEnforceVersion8 bool
// ACLEnableKeyListPolicy ???
//
// hcl: acl_enable_key_list_policy = (true|false)
ACLEnableKeyListPolicy bool
// ACLMasterToken is used to bootstrap the ACL system. It should be specified
// on the servers in the ACLDatacenter. When the leader comes online, it ensures
// that the Master token is available. This provides the initial token.
//
// hcl: acl_master_token = string
ACLMasterToken string
// ACLReplicationToken is used to fetch ACLs from the ACLDatacenter in
// order to replicate them locally. Setting this to a non-empty value
// also enables replication. Replication is only available in datacenters
// other than the ACLDatacenter.
//
// hcl: acl_replication_token = string
ACLReplicationToken string
// ACLTTL is used to control the time-to-live of cached ACLs . This has
// a major impact on performance. By default, it is set to 30 seconds.
//
// hcl: acl_ttl = "duration"
ACLTTL time.Duration
// ACLToken is the default token used to make requests if a per-request
// token is not provided. If not configured the 'anonymous' token is used.
//
// hcl: acl_token = string
ACLToken string
// AutopilotCleanupDeadServers enables the automatic cleanup of dead servers when new ones
// are added to the peer list. Defaults to true.
//
// hcl: autopilot { cleanup_dead_servers = (true|false) }
AutopilotCleanupDeadServers bool
// AutopilotDisableUpgradeMigration will disable Autopilot's upgrade migration
// strategy of waiting until enough newer-versioned servers have been added to the
// cluster before promoting them to voters. (Enterprise-only)
//
// hcl: autopilot { disable_upgrade_migration = (true|false)
AutopilotDisableUpgradeMigration bool
// AutopilotLastContactThreshold is the limit on the amount of time a server can go
// without leader contact before being considered unhealthy.
//
// hcl: autopilot { last_contact_threshold = "duration" }
AutopilotLastContactThreshold time.Duration
// AutopilotMaxTrailingLogs is the amount of entries in the Raft Log that a server can
// be behind before being considered unhealthy. The value must be positive.
//
// hcl: autopilot { max_trailing_logs = int }
AutopilotMaxTrailingLogs int
// AutopilotRedundancyZoneTag is the Meta tag to use for separating servers
// into zones for redundancy. If left blank, this feature will be disabled.
// (Enterprise-only)
//
// hcl: autopilot { redundancy_zone_tag = string }
AutopilotRedundancyZoneTag string
// AutopilotServerStabilizationTime is the minimum amount of time a server must be
// in a stable, healthy state before it can be added to the cluster. Only
// applicable with Raft protocol version 3 or higher.
//
// hcl: autopilot { server_stabilization_time = "duration" }
AutopilotServerStabilizationTime time.Duration
// AutopilotUpgradeVersionTag is the node tag to use for version info when
// performing upgrade migrations. If left blank, the Consul version will be used.
//
// (Entrprise-only)
//
// hcl: autopilot { upgrade_version_tag = string }
AutopilotUpgradeVersionTag string
// DNSAllowStale is used to enable lookups with stale
// data. This gives horizontal read scalability since
// any Consul server can service the query instead of
// only the leader.
//
// hcl: dns_config { allow_stale = (true|false) }
DNSAllowStale bool
// DNSDisableCompression is used to control whether DNS responses are
// compressed. In Consul 0.7 this was turned on by default and this
// config was added as an opt-out.
//
// hcl: dns_config { disable_compression = (true|false) }
DNSDisableCompression bool
// DNSDomain is the DNS domain for the records. Should end with a dot.
// Defaults to "consul."
//
// hcl: domain = string
// flag: -domain string
DNSDomain string
// DNSEnableTruncate is used to enable setting the truncate
// flag for UDP DNS queries. This allows unmodified
// clients to re-query the consul server using TCP
// when the total number of records exceeds the number
// returned by default for UDP.
//
// hcl: dns_config { enable_truncate = (true|false) }
DNSEnableTruncate bool
// DNSMaxStale is used to bound how stale of a result is
// accepted for a DNS lookup. This can be used with
// AllowStale to limit how old of a value is served up.
// If the stale result exceeds this, another non-stale
// stale read is performed.
//
// hcl: dns_config { max_stale = "duration" }
DNSMaxStale time.Duration
// DNSNodeTTL provides the TTL value for a node query.
//
// hcl: dns_config { node_ttl = "duration" }
DNSNodeTTL time.Duration
// DNSOnlyPassing is used to determine whether to filter nodes
// whose health checks are in any non-passing state. By
// default, only nodes in a critical state are excluded.
//
// hcl: dns_config { only_passing = "duration" }
DNSOnlyPassing bool
// DNSRecursorTimeout specifies the timeout in seconds
// for Consul's internal dns client used for recursion.
// This value is used for the connection, read and write timeout.
//
// hcl: dns_config { recursor_timeout = "duration" }
DNSRecursorTimeout time.Duration
// DNSServiceTTL provides the TTL value for a service
// query for given service. The "*" wildcard can be used
// to set a default for all services.
//
// hcl: dns_config { service_ttl = map[string]"duration" }
DNSServiceTTL map[string]time.Duration
// DNSUDPAnswerLimit is used to limit the maximum number of DNS Resource
// Records returned in the ANSWER section of a DNS response. This is
// not normally useful and will be limited based on the querying
// protocol, however systems that implemented §6 Rule 9 in RFC3484
// may want to set this to `1` in order to subvert §6 Rule 9 and
// re-obtain the effect of randomized resource records (i.e. each
// answer contains only one IP, but the IP changes every request).
// RFC3484 sorts answers in a deterministic order, which defeats the
// purpose of randomized DNS responses. This RFC has been obsoleted
// by RFC6724 and restores the desired behavior of randomized
// responses, however a large number of Linux hosts using glibc(3)
// implemented §6 Rule 9 and may need this option (e.g. CentOS 5-6,
// Debian Squeeze, etc).
//
// hcl: dns_config { udp_answer_limit = int }
DNSUDPAnswerLimit int
// DNSRecursors can be set to allow the DNS servers to recursively
// resolve non-consul domains.
//
// hcl: recursors = []string
// flag: -recursor string [-recursor string]
DNSRecursors []string
// HTTPBlockEndpoints is a list of endpoint prefixes to block in the
// HTTP API. Any requests to these will get a 403 response.
//
// hcl: http_config { block_endpoints = []string }
HTTPBlockEndpoints []string
// HTTPResponseHeaders are used to add HTTP header response fields to the HTTP API responses.
//
// hcl: http_config { response_headers = map[string]string }
HTTPResponseHeaders map[string]string
// TelemetryCirconus*: see https://github.com/circonus-labs/circonus-gometrics
// for more details on the various configuration options.
// Valid configuration combinations:
// - CirconusAPIToken
// metric management enabled (search for existing check or create a new one)
// - CirconusSubmissionUrl
// metric management disabled (use check with specified submission_url,
// broker must be using a public SSL certificate)
// - CirconusAPIToken + CirconusCheckSubmissionURL
// metric management enabled (use check with specified submission_url)
// - CirconusAPIToken + CirconusCheckID
// metric management enabled (use check with specified id)
// TelemetryCirconusAPIApp is an app name associated with API token.
// Default: "consul"
//
// hcl: telemetry { circonus_api_app = string }
TelemetryCirconusAPIApp string
// TelemetryCirconusAPIToken is a valid API Token used to create/manage check. If provided,
// metric management is enabled.
// Default: none
//
// hcl: telemetry { circonous_api_token = string }
TelemetryCirconusAPIToken string
// TelemetryCirconusAPIURL is the base URL to use for contacting the Circonus API.
// Default: "https://api.circonus.com/v2"
//
// hcl: telemetry { circonus_api_url = string }
TelemetryCirconusAPIURL string
// TelemetryCirconusBrokerID is an explicit broker to use when creating a new check. The numeric portion
// of broker._cid. If metric management is enabled and neither a Submission URL nor Check ID
// is provided, an attempt will be made to search for an existing check using Instance ID and
// Search Tag. If one is not found, a new HTTPTRAP check will be created.
// Default: use Select Tag if provided, otherwise, a random Enterprise Broker associated
// with the specified API token or the default Circonus Broker.
// Default: none
//
// hcl: telemetry { circonus_broker_id = string }
TelemetryCirconusBrokerID string
// TelemetryCirconusBrokerSelectTag is a special tag which will be used to select a broker when
// a Broker ID is not provided. The best use of this is to as a hint for which broker
// should be used based on *where* this particular instance is running.
// (e.g. a specific geo location or datacenter, dc:sfo)
// Default: none
//
// hcl: telemetry { circonus_broker_select_tag = string }
TelemetryCirconusBrokerSelectTag string
// TelemetryCirconusCheckDisplayName is the name for the check which will be displayed in the Circonus UI.
// Default: value of CirconusCheckInstanceID
//
// hcl: telemetry { circonus_check_display_name = string }
TelemetryCirconusCheckDisplayName string
// TelemetryCirconusCheckForceMetricActivation will force enabling metrics, as they are encountered,
// if the metric already exists and is NOT active. If check management is enabled, the default
// behavior is to add new metrics as they are encoutered. If the metric already exists in the
// check, it will *NOT* be activated. This setting overrides that behavior.
// Default: "false"
//
// hcl: telemetry { circonus_check_metrics_activation = (true|false)
TelemetryCirconusCheckForceMetricActivation string
// TelemetryCirconusCheckID is the check id (not check bundle id) from a previously created
// HTTPTRAP check. The numeric portion of the check._cid field.
// Default: none
//
// hcl: telemetry { circonus_check_id = string }
TelemetryCirconusCheckID string
// TelemetryCirconusCheckInstanceID serves to uniquely identify the metrics coming from this "instance".
// It can be used to maintain metric continuity with transient or ephemeral instances as
// they move around within an infrastructure.
// Default: hostname:app
//
// hcl: telemetry { circonus_check_instance_id = string }
TelemetryCirconusCheckInstanceID string
// TelemetryCirconusCheckSearchTag is a special tag which, when coupled with the instance id, helps to
// narrow down the search results when neither a Submission URL or Check ID is provided.
// Default: service:app (e.g. service:consul)
//
// hcl: telemetry { circonus_check_search_tag = string }
TelemetryCirconusCheckSearchTag string
// TelemetryCirconusCheckSearchTag is a special tag which, when coupled with the instance id, helps to
// narrow down the search results when neither a Submission URL or Check ID is provided.
// Default: service:app (e.g. service:consul)
//
// hcl: telemetry { circonus_check_tags = string }
TelemetryCirconusCheckTags string
// TelemetryCirconusSubmissionInterval is the interval at which metrics are submitted to Circonus.
// Default: 10s
//
// hcl: telemetry { circonus_submission_interval = "duration" }
TelemetryCirconusSubmissionInterval string
// TelemetryCirconusCheckSubmissionURL is the check.config.submission_url field from a
// previously created HTTPTRAP check.
// Default: none
//
// hcl: telemetry { circonus_submission_url = string }
TelemetryCirconusSubmissionURL string
// DisableHostname will disable hostname prefixing for all metrics.
//
// hcl: telemetry { disable_hostname = (true|false)
TelemetryDisableHostname bool
// TelemetryDogStatsdAddr is the address of a dogstatsd instance. If provided,
// metrics will be sent to that instance
//
// hcl: telemetry { dogstatsd_addr = string }
TelemetryDogstatsdAddr string
// TelemetryDogStatsdTags are the global tags that should be sent with each packet to dogstatsd
// It is a list of strings, where each string looks like "my_tag_name:my_tag_value"
//
// hcl: telemetry { dogstatsd_tags = []string }
TelemetryDogstatsdTags []string
// TelemetryFilterDefault is the default for whether to allow a metric that's not
// covered by the filter.
//
// hcl: telemetry { filter_default = (true|false) }
TelemetryFilterDefault bool
// TelemetryAllowedPrefixes is a list of filter rules to apply for allowing metrics
// by prefix. Use the 'prefix_filter' option and prefix rules with '+' to be
// included.
//
// hcl: telemetry { prefix_filter = []string{"+<expr>", "+<expr>", ...} }
TelemetryAllowedPrefixes []string
// TelemetryBlockedPrefixes is a list of filter rules to apply for blocking metrics
// by prefix. Use the 'prefix_filter' option and prefix rules with '-' to be
// excluded.
//
// hcl: telemetry { prefix_filter = []string{"-<expr>", "-<expr>", ...} }
TelemetryBlockedPrefixes []string
// TelemetryMetricsPrefix is the prefix used to write stats values to.
// Default: "consul."
//
// hcl: telemetry { metrics_prefix = string }
TelemetryMetricsPrefix string
// TelemetryStatsdAddr is the address of a statsd instance. If provided,
// metrics will be sent to that instance.
//
// hcl: telemetry { statsd_addr = string }
TelemetryStatsdAddr string
// TelemetryStatsiteAddr is the address of a statsite instance. If provided,
// metrics will be streamed to that instance.
//
// hcl: telemetry { statsite_addr = string }
TelemetryStatsiteAddr string
// Datacenter and NodeName are exposed via /v1/agent/self from here and
// used in lots of places like CLI commands. Treat this as an interface
// that must be stable.
Datacenter string
NodeName string
AdvertiseAddrLAN *net.IPAddr
AdvertiseAddrWAN *net.IPAddr
BindAddr *net.IPAddr
// Bootstrap is used to bring up the first Consul server, and
// permits that node to elect itself leader
//
// hcl: bootstrap = (true|false)
// flag: -bootstrap
Bootstrap bool
// BootstrapExpect tries to automatically bootstrap the Consul cluster,
// by withholding peers until enough servers join.
//
// hcl: bootstrap_expect = int
// flag: -bootstrap-expect=int
BootstrapExpect int
CAFile string
CAPath string
CertFile string
CheckUpdateInterval time.Duration
Checks []*structs.CheckDefinition
ClientAddrs []*net.IPAddr
DNSAddrs []net.Addr
DNSPort int
DataDir string
// DevMode enables a fast-path mode of operation to bring up an in-memory
// server with minimal configuration. Useful for developing Consul.
//
// flag: -dev
DevMode bool
DisableAnonymousSignature bool
DisableCoordinates bool
DisableHostNodeID bool
DisableKeyringFile bool
DisableRemoteExec bool
DisableUpdateCheck bool
DiscardCheckOutput bool
// EnableACLReplication is used to turn on ACL replication when using
// /v1/agent/token/acl_replication_token to introduce the token, instead
// of setting acl_replication_token in the config. Setting the token via
// config will also set this to true for backward compatibility.
//
// hcl: enable_acl_replication = (true|false)
// todo(fs): rename to ACLEnableReplication
EnableACLReplication bool
EnableDebug bool
EnableScriptChecks bool
EnableSyslog bool
EnableUI bool
EncryptKey string
EncryptVerifyIncoming bool
EncryptVerifyOutgoing bool
HTTPAddrs []net.Addr
HTTPPort int
HTTPSAddrs []net.Addr
HTTPSPort int
KeyFile string
LeaveDrainTime time.Duration
LeaveOnTerm bool
LogLevel string
NodeID types.NodeID
NodeMeta map[string]string
NonVotingServer bool
PidFile string
RPCAdvertiseAddr *net.TCPAddr
RPCBindAddr *net.TCPAddr
RPCHoldTimeout time.Duration
// RPCRateLimit and RPCMaxBurst control how frequently RPC calls are allowed
// to happen. In any large enough time interval, rate limiter limits the
// rate to RPCRate tokens per second, with a maximum burst size of
// RPCMaxBurst events. As a special case, if RPCRate == Inf (the infinite
// rate), RPCMaxBurst is ignored.
//
// See https://en.wikipedia.org/wiki/Token_bucket for more about token
// buckets.
//
// hcl: limit { rpc_rate = (float64|MaxFloat64) rpc_max_burst = int }
RPCRateLimit rate.Limit
RPCMaxBurst int
RPCProtocol int
RaftProtocol int
ReconnectTimeoutLAN time.Duration
ReconnectTimeoutWAN time.Duration
RejoinAfterLeave bool
RetryJoinIntervalLAN time.Duration
RetryJoinIntervalWAN time.Duration
RetryJoinLAN []string
RetryJoinMaxAttemptsLAN int
RetryJoinMaxAttemptsWAN int
RetryJoinWAN []string
SegmentName string
Segments []structs.NetworkSegment
SerfAdvertiseAddrLAN *net.TCPAddr
SerfAdvertiseAddrWAN *net.TCPAddr
SerfBindAddrLAN *net.TCPAddr
SerfBindAddrWAN *net.TCPAddr
SerfPortLAN int
SerfPortWAN int
ServerMode bool
ServerName string
ServerPort int
Services []*structs.ServiceDefinition
SessionTTLMin time.Duration
SkipLeaveOnInt bool
StartJoinAddrsLAN []string
StartJoinAddrsWAN []string
SyslogFacility string
TLSCipherSuites []uint16
TLSMinVersion string
TLSPreferServerCipherSuites bool
TaggedAddresses map[string]string
TranslateWANAddrs bool
UIDir string
UnixSocketGroup string
UnixSocketMode string
UnixSocketUser string
VerifyIncoming bool
VerifyIncomingHTTPS bool
VerifyIncomingRPC bool
VerifyOutgoing bool
VerifyServerHostname bool
Watches []map[string]interface{}
}
// IncomingHTTPSConfig returns the TLS configuration for HTTPS
// connections to consul.
func (c *RuntimeConfig) IncomingHTTPSConfig() (*tls.Config, error) {
tc := &tlsutil.Config{
VerifyIncoming: c.VerifyIncoming || c.VerifyIncomingHTTPS,
VerifyOutgoing: c.VerifyOutgoing,
CAFile: c.CAFile,
CAPath: c.CAPath,
CertFile: c.CertFile,
KeyFile: c.KeyFile,
NodeName: c.NodeName,
ServerName: c.ServerName,
TLSMinVersion: c.TLSMinVersion,
CipherSuites: c.TLSCipherSuites,
PreferServerCipherSuites: c.TLSPreferServerCipherSuites,
}
return tc.IncomingTLSConfig()
}
// Sanitized returns a JSON/HCL compatible representation of the runtime
// configuration where all fields with potential secrets had their
// values replaced by 'hidden'. In addition, network addresses and
// time.Duration values are formatted to improve readability.
func (c *RuntimeConfig) Sanitized() map[string]interface{} {
return sanitize("rt", reflect.ValueOf(c)).Interface().(map[string]interface{})
}
// isSecret determines whether a field name represents a field which
// may contain a secret.
func isSecret(name string) bool {
name = strings.ToLower(name)
return strings.Contains(name, "key") || strings.Contains(name, "token") || strings.Contains(name, "secret")
}
// cleanRetryJoin sanitizes the go-discover config strings key=val key=val...
// by scrubbing the individual key=val combinations.
func cleanRetryJoin(a string) string {
var fields []string
for _, f := range strings.Fields(a) {
if isSecret(f) {
kv := strings.SplitN(f, "=", 2)
fields = append(fields, kv[0]+"=hidden")
} else {
fields = append(fields, f)
}
}
return strings.Join(fields, " ")
}
func sanitize(name string, v reflect.Value) reflect.Value {
typ := v.Type()
switch {
// check before isStruct and isPtr
case isNetAddr(typ):
if v.IsNil() {
return reflect.ValueOf("")
}
switch x := v.Interface().(type) {
case *net.TCPAddr:
return reflect.ValueOf("tcp://" + x.String())
case *net.UDPAddr:
return reflect.ValueOf("udp://" + x.String())
case *net.UnixAddr:
return reflect.ValueOf("unix://" + x.String())
case *net.IPAddr:
return reflect.ValueOf(x.IP.String())
default:
return v
}
// check before isNumber
case isDuration(typ):
x := v.Interface().(time.Duration)
return reflect.ValueOf(x.String())
case isString(typ):
if strings.HasPrefix(name, "RetryJoinLAN[") || strings.HasPrefix(name, "RetryJoinWAN[") {
x := v.Interface().(string)
return reflect.ValueOf(cleanRetryJoin(x))
}
if isSecret(name) {
return reflect.ValueOf("hidden")
}
return v
case isNumber(typ) || isBool(typ):
return v
case isPtr(typ):
if v.IsNil() {
return v
}
return sanitize(name, v.Elem())
case isStruct(typ):
m := map[string]interface{}{}
for i := 0; i < typ.NumField(); i++ {
key := typ.Field(i).Name
m[key] = sanitize(key, v.Field(i)).Interface()
}
return reflect.ValueOf(m)
case isArray(typ) || isSlice(typ):
ma := make([]interface{}, 0)
for i := 0; i < v.Len(); i++ {
ma = append(ma, sanitize(fmt.Sprintf("%s[%d]", name, i), v.Index(i)).Interface())
}
return reflect.ValueOf(ma)
case isMap(typ):
m := map[string]interface{}{}
for _, k := range v.MapKeys() {
key := k.String()
m[key] = sanitize(key, v.MapIndex(k)).Interface()
}
return reflect.ValueOf(m)
default:
return v
}
}
func isDuration(t reflect.Type) bool { return t == reflect.TypeOf(time.Second) }
func isMap(t reflect.Type) bool { return t.Kind() == reflect.Map }
func isNetAddr(t reflect.Type) bool { return t.Implements(reflect.TypeOf((*net.Addr)(nil)).Elem()) }
func isPtr(t reflect.Type) bool { return t.Kind() == reflect.Ptr }
func isArray(t reflect.Type) bool { return t.Kind() == reflect.Array }
func isSlice(t reflect.Type) bool { return t.Kind() == reflect.Slice }
func isString(t reflect.Type) bool { return t.Kind() == reflect.String }
func isStruct(t reflect.Type) bool { return t.Kind() == reflect.Struct }
func isBool(t reflect.Type) bool { return t.Kind() == reflect.Bool }
func isNumber(t reflect.Type) bool { return isInt(t) || isUint(t) || isFloat(t) || isComplex(t) }
func isInt(t reflect.Type) bool {
return t.Kind() == reflect.Int ||
t.Kind() == reflect.Int8 ||
t.Kind() == reflect.Int16 ||
t.Kind() == reflect.Int32 ||
t.Kind() == reflect.Int64
}
func isUint(t reflect.Type) bool {
return t.Kind() == reflect.Uint ||
t.Kind() == reflect.Uint8 ||
t.Kind() == reflect.Uint16 ||
t.Kind() == reflect.Uint32 ||
t.Kind() == reflect.Uint64
}
func isFloat(t reflect.Type) bool { return t.Kind() == reflect.Float32 || t.Kind() == reflect.Float64 }
func isComplex(t reflect.Type) bool {
return t.Kind() == reflect.Complex64 || t.Kind() == reflect.Complex128
}