A api/agent.go

@@ -0,0 +1,106 @@ 
+package api
+
+// AgentMember represents a cluster member known to the agent
+type AgentMember struct {
+	Name string
+	Addr string
+	Port uint16
+	Tags map[string]string
+	// Status of the Member which corresponds to  github.com/hashicorp/serf/serf.MemberStatus
+	// Value is one of:
+	//
+	// 	  AgentMemberNone    = 0
+	//	  AgentMemberAlive   = 1
+	//	  AgentMemberLeaving = 2
+	//	  AgentMemberLeft    = 3
+	//	  AgentMemberFailed  = 4
+	Status      int
+	ProtocolMin uint8
+	ProtocolMax uint8
+	ProtocolCur uint8
+	DelegateMin uint8
+	DelegateMax uint8
+	DelegateCur uint8
+}
+
+// XXX: this may be needed for consul compatability, but I'm leaving it
+// out for now in case it isn't.
+// const AllSegments = "_all"
+
+// Agent can be used to query the Agent endpoints
+type Agent struct {
+	c *Client
+
+	// cache the node name
+	nodeName string
+}
+
+// Agent returns a handle to the agent endpoints
+func (c *Client) Agent() *Agent {
+	return &Agent{c: c}
+}
+
+// Self is used to query the agent we are speaking to for
+// information about itself
+func (a *Agent) Self() (map[string]map[string]interface{}, error) {
+	r := a.c.newRequest("GET", "/v1/agent/self")
+	_, resp, err := requireOK(a.c.doRequest(r))
+	if err != nil {
+		return nil, err
+	}
+	defer closeResponseBody(resp)
+
+	var out map[string]map[string]interface{}
+	if err := decodeBody(resp, &out); err != nil {
+		return nil, err
+	}
+	return out, nil
+}
+
+// Host is used to retrieve information about the host the
+// agent is running on such as CPU, memory, and disk. Requires
+// a operator:read ACL token.
+func (a *Agent) Host() (map[string]interface{}, error) {
+	r := a.c.newRequest("GET", "/v1/agent/host")
+	_, resp, err := requireOK(a.c.doRequest(r))
+	if err != nil {
+		return nil, err
+	}
+	defer closeResponseBody(resp)
+
+	var out map[string]interface{}
+	if err := decodeBody(resp, &out); err != nil {
+		return nil, err
+	}
+	return out, nil
+}
+
+// NodeName is used to get the node name of the agent
+func (a *Agent) NodeName() (string, error) {
+	if a.nodeName != "" {
+		return a.nodeName, nil
+	}
+	info, err := a.Self()
+	if err != nil {
+		return "", err
+	}
+	name := info["Config"]["NodeName"].(string)
+	a.nodeName = name
+	return name, nil
+}
+
+// Members returns the known serf gossip members
+func (a *Agent) Members() ([]*AgentMember, error) {
+	r := a.c.newRequest("GET", "/v1/agent/members")
+	_, resp, err := requireOK(a.c.doRequest(r))
+	if err != nil {
+		return nil, err
+	}
+	defer closeResponseBody(resp)
+
+	var out []*AgentMember
+	if err := decodeBody(resp, &out); err != nil {
+		return nil, err
+	}
+	return out, nil
+}

M api/api.go → api/api.go

@@ -0,0 +1,483 @@ 
+package api
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"net"
+	"net/http"
+	"net/url"
+	"strconv"
+	"strings"
+	"sync"
+	"time"
+
+	"git.j3s.sh/cascade/lib/cleanhttp"
+)
+
+// Config is used to configure the creation of a client
+type Config struct {
+	// Address is the address of the Consul server
+	Address string
+
+	// Scheme is the URI scheme for the Consul server
+	Scheme string
+
+	// Transport is the Transport to use for the http client.
+	Transport *http.Transport
+
+	// HttpClient is the client to use. Default will be
+	// used if not provided.
+	HttpClient *http.Client
+
+	// WaitTime limits how long a Watch will block. If not provided,
+	// the agent default values will be used.
+	WaitTime time.Duration
+}
+
+// DefaultConfig returns a default configuration for the client. By default this
+// will pool and reuse idle connections to cascade. If you have a long-lived
+// client object, this is the desired behavior and should make the most efficient
+// use of the connections to cascade. If you don't reuse a client object, which
+// is not recommended, then you may notice idle connections building up over
+// time. To avoid this, use the DefaultNonPooledConfig() instead.
+func DefaultConfig() *Config {
+	return defaultConfig(cleanhttp.DefaultPooledTransport)
+}
+
+// DefaultNonPooledConfig returns a default configuration for the client which
+// does not pool connections. This isn't a recommended configuration because it
+// will reconnect to cascade on every request, but this is useful to avoid the
+// accumulation of idle connections if you make many client objects during the
+// lifetime of your application.
+func DefaultNonPooledConfig() *Config {
+	return defaultConfig(cleanhttp.DefaultTransport)
+}
+
+// defaultConfig returns the default configuration for the client, using the
+// given function to make the transport.
+func defaultConfig(transportFn func() *http.Transport) *Config {
+	config := &Config{
+		Address:   "127.0.0.1:8500",
+		Scheme:    "http",
+		Transport: transportFn(),
+	}
+
+	return config
+}
+
+// Client provides a client to the Consul API
+type Client struct {
+	modifyLock sync.RWMutex
+	headers    http.Header
+
+	config Config
+}
+
+// Headers gets the current set of headers used for requests. This returns a
+// copy; to modify it call AddHeader or SetHeaders.
+func (c *Client) Headers() http.Header {
+	c.modifyLock.RLock()
+	defer c.modifyLock.RUnlock()
+
+	if c.headers == nil {
+		return nil
+	}
+
+	ret := make(http.Header)
+	for k, v := range c.headers {
+		for _, val := range v {
+			ret[k] = append(ret[k], val)
+		}
+	}
+
+	return ret
+}
+
+// AddHeader allows a single header key/value pair to be added
+// in a race-safe fashion.
+func (c *Client) AddHeader(key, value string) {
+	c.modifyLock.Lock()
+	defer c.modifyLock.Unlock()
+	c.headers.Add(key, value)
+}
+
+// SetHeaders clears all previous headers and uses only the given
+// ones going forward.
+func (c *Client) SetHeaders(headers http.Header) {
+	c.modifyLock.Lock()
+	defer c.modifyLock.Unlock()
+	c.headers = headers
+}
+
+// NewClient returns a new client
+func NewClient(config *Config) (*Client, error) {
+	// bootstrap the config
+	defConfig := DefaultConfig()
+
+	if config.Address == "" {
+		config.Address = defConfig.Address
+	}
+
+	if config.Scheme == "" {
+		config.Scheme = defConfig.Scheme
+	}
+
+	if config.Transport == nil {
+		config.Transport = defConfig.Transport
+	}
+
+	if config.HttpClient == nil {
+		config.HttpClient = NewHttpClient(config.Transport)
+	}
+
+	parts := strings.SplitN(config.Address, "://", 2)
+	if len(parts) == 2 {
+		switch parts[0] {
+		case "http":
+			config.Scheme = "http"
+		// TODO: unix socket support? do i care? no???
+		default:
+			return nil, fmt.Errorf("Unknown protocol scheme: %s", parts[0])
+		}
+		config.Address = parts[1]
+	}
+
+	return &Client{config: *config, headers: make(http.Header)}, nil
+}
+
+// NewHttpClient returns an http client configured with the given Transport
+func NewHttpClient(transport *http.Transport) *http.Client {
+	client := &http.Client{
+		Transport: transport,
+	}
+	return client
+}
+
+// request is used to help build up a request
+type request struct {
+	config *Config
+	method string
+	url    *url.URL
+	params url.Values
+	body   io.Reader
+	header http.Header
+	obj    interface{}
+	ctx    context.Context
+}
+
+// QueryMeta is used to return meta data about a query
+type QueryMeta struct {
+	// LastIndex. This can be used as a WaitIndex to perform
+	// a blocking query
+	LastIndex uint64
+
+	// LastContentHash. This can be used as a WaitHash to perform a blocking query
+	// for endpoints that support hash-based blocking. Endpoints that do not
+	// support it will return an empty hash.
+	LastContentHash string
+
+	// How long did the request take
+	RequestTime time.Duration
+
+	// Is address translation enabled for HTTP responses on this agent
+	AddressTranslationEnabled bool
+}
+
+// QueryOptions are used to parameterize a query
+type QueryOptions struct {
+	// WaitIndex is used to enable a blocking query. Waits
+	// until the timeout or the next index is reached
+	WaitIndex uint64
+
+	// WaitHash is used by some endpoints instead of WaitIndex to perform blocking
+	// on state based on a hash of the response rather than a monotonic index.
+	// This is required when the state being blocked on is not stored in Raft, for
+	// example agent-local proxy configuration.
+	WaitHash string
+
+	// WaitTime is used to bound the duration of a wait.
+	// Defaults to that of the Config, but can be overridden.
+	WaitTime time.Duration
+
+	// Near is used to provide a node name that will sort the results
+	// in ascending order based on the estimated round trip time from
+	// that node. Setting this to "_agent" will use the agent's node
+	// for the sort.
+	Near string
+
+	// NodeMeta is used to filter results by nodes with the given
+	// metadata key/value pairs. Currently, only one key/value pair can
+	// be provided for filtering.
+	NodeMeta map[string]string
+
+	// ctx is an optional context pass through to the underlying HTTP
+	// request layer. Use Context() and WithContext() to manage this.
+	ctx context.Context
+
+	// Filter requests filtering data prior to it being returned. The string
+	// is a go-bexpr compatible expression.
+	Filter string
+}
+
+// setQueryOptions is used to annotate the request with
+// additional query options
+func (r *request) setQueryOptions(q *QueryOptions) {
+	if q == nil {
+		return
+	}
+	if q.WaitIndex != 0 {
+		r.params.Set("index", strconv.FormatUint(q.WaitIndex, 10))
+	}
+	if q.WaitTime != 0 {
+		r.params.Set("wait", durToMsec(q.WaitTime))
+	}
+	if q.WaitHash != "" {
+		r.params.Set("hash", q.WaitHash)
+	}
+	if q.Near != "" {
+		r.params.Set("near", q.Near)
+	}
+	if q.Filter != "" {
+		r.params.Set("filter", q.Filter)
+	}
+	if len(q.NodeMeta) > 0 {
+		for key, value := range q.NodeMeta {
+			r.params.Add("node-meta", key+":"+value)
+		}
+	}
+
+	r.ctx = q.ctx
+}
+
+// durToMsec converts a duration to a millisecond specified string. If the
+// user selected a positive value that rounds to 0 ms, then we will use 1 ms
+// so they get a short delay, otherwise Consul will translate the 0 ms into
+// a huge default delay.
+func durToMsec(dur time.Duration) string {
+	ms := dur / time.Millisecond
+	if dur > 0 && ms == 0 {
+		ms = 1
+	}
+	return fmt.Sprintf("%dms", ms)
+}
+
+// serverError is a string we look for to detect 500 errors.
+const serverError = "Unexpected response code: 500"
+
+// IsRetryableError returns true for 500 errors from the Consul servers, and
+// network connection errors. These are usually retryable at a later time.
+// This applies to reads but NOT to writes. This may return true for errors
+// on writes that may have still gone through, so do not use this to retry
+// any write operations.
+func IsRetryableError(err error) bool {
+	if err == nil {
+		return false
+	}
+
+	if _, ok := err.(net.Error); ok {
+		return true
+	}
+
+	// TODO (slackpad) - Make a real error type here instead of using
+	// a string check.
+	return strings.Contains(err.Error(), serverError)
+}
+
+// toHTTP converts the request to an HTTP request
+func (r *request) toHTTP() (*http.Request, error) {
+	// Encode the query parameters
+	r.url.RawQuery = r.params.Encode()
+
+	// Check if we should encode the body
+	if r.body == nil && r.obj != nil {
+		b, err := encodeBody(r.obj)
+		if err != nil {
+			return nil, err
+		}
+		r.body = b
+	}
+
+	// Create the HTTP request
+	req, err := http.NewRequest(r.method, r.url.RequestURI(), r.body)
+	if err != nil {
+		return nil, err
+	}
+
+	req.URL.Host = r.url.Host
+	req.URL.Scheme = r.url.Scheme
+	req.Host = r.url.Host
+	req.Header = r.header
+
+	// Content-Type must always be set when a body is present
+	// See https://github.com/hashicorp/consul/issues/10011
+	if req.Body != nil && req.Header.Get("Content-Type") == "" {
+		req.Header.Set("Content-Type", "application/json")
+	}
+
+	if r.ctx != nil {
+		return req.WithContext(r.ctx), nil
+	}
+
+	return req, nil
+}
+
+// newRequest is used to create a new request
+func (c *Client) newRequest(method, path string) *request {
+	r := &request{
+		config: &c.config,
+		method: method,
+		url: &url.URL{
+			Scheme: c.config.Scheme,
+			Host:   c.config.Address,
+			Path:   path,
+		},
+		params: make(map[string][]string),
+		header: c.Headers(),
+	}
+
+	if c.config.WaitTime != 0 {
+		r.params.Set("wait", durToMsec(r.config.WaitTime))
+	}
+
+	return r
+}
+
+// doRequest runs a request with our client
+func (c *Client) doRequest(r *request) (time.Duration, *http.Response, error) {
+	req, err := r.toHTTP()
+	if err != nil {
+		return 0, nil, err
+	}
+	start := time.Now()
+	resp, err := c.config.HttpClient.Do(req)
+	diff := time.Since(start)
+	return diff, resp, err
+}
+
+// Query is used to do a GET request against an endpoint
+// and deserialize the response into an interface using
+// standard cascade conventions.
+func (c *Client) query(endpoint string, out interface{}, q *QueryOptions) (*QueryMeta, error) {
+	r := c.newRequest("GET", endpoint)
+	r.setQueryOptions(q)
+	rtt, resp, err := c.doRequest(r)
+	if err != nil {
+		return nil, err
+	}
+	defer closeResponseBody(resp)
+
+	qm := &QueryMeta{}
+	err = parseQueryMeta(resp, qm)
+	if err != nil {
+		return nil, err
+	}
+	qm.RequestTime = rtt
+
+	if err := decodeBody(resp, out); err != nil {
+		return nil, err
+	}
+	return qm, nil
+}
+
+// parseQueryMeta is used to help parse query meta-data
+func parseQueryMeta(resp *http.Response, q *QueryMeta) error {
+	header := resp.Header
+
+	// Parse the X-Consul-Index (if it's set - hash based blocking queries don't
+	// set this)
+	//	if indexStr := header.Get("X-Consul-Index"); indexStr != "" {
+	//		index, err := strconv.ParseUint(indexStr, 10, 64)
+	//		if err != nil {
+	//			return fmt.Errorf("Failed to parse X-Consul-Index: %v", err)
+	//		}
+	//		q.LastIndex = index
+	//	}
+	//	q.LastContentHash = header.Get("X-Consul-ContentHash")
+
+	// Parse X-Consul-Translate-Addresses
+	switch header.Get("X-Consul-Translate-Addresses") {
+	case "true":
+		q.AddressTranslationEnabled = true
+	default:
+		q.AddressTranslationEnabled = false
+	}
+
+	return nil
+}
+
+// decodeBody is used to JSON decode a body
+func decodeBody(resp *http.Response, out interface{}) error {
+	dec := json.NewDecoder(resp.Body)
+	return dec.Decode(out)
+}
+
+// encodeBody is used to encode a request body
+func encodeBody(obj interface{}) (io.Reader, error) {
+	buf := bytes.NewBuffer(nil)
+	enc := json.NewEncoder(buf)
+	if err := enc.Encode(obj); err != nil {
+		return nil, err
+	}
+	return buf, nil
+}
+
+// requireOK is used to wrap doRequest and check for a 200
+func requireOK(d time.Duration, resp *http.Response, e error) (time.Duration, *http.Response, error) {
+	if e != nil {
+		if resp != nil {
+			closeResponseBody(resp)
+		}
+		return d, nil, e
+	}
+	if resp.StatusCode != 200 {
+		return d, nil, generateUnexpectedResponseCodeError(resp)
+	}
+	return d, resp, nil
+}
+
+// closeResponseBody reads resp.Body until EOF, and then closes it. The read
+// is necessary to ensure that the http.Client's underlying RoundTripper is able
+// to re-use the TCP connection. See godoc on net/http.Client.Do.
+func closeResponseBody(resp *http.Response) error {
+	_, _ = io.Copy(ioutil.Discard, resp.Body)
+	return resp.Body.Close()
+}
+
+func (req *request) filterQuery(filter string) {
+	if filter == "" {
+		return
+	}
+
+	req.params.Set("filter", filter)
+}
+
+// generateUnexpectedResponseCodeError consumes the rest of the body, closes
+// the body stream and generates an error indicating the status code was
+// unexpected.
+func generateUnexpectedResponseCodeError(resp *http.Response) error {
+	var buf bytes.Buffer
+	io.Copy(&buf, resp.Body)
+	closeResponseBody(resp)
+	return fmt.Errorf("Unexpected response code: %d (%s)", resp.StatusCode, buf.Bytes())
+}
+
+func requireNotFoundOrOK(d time.Duration, resp *http.Response, e error) (bool, time.Duration, *http.Response, error) {
+	if e != nil {
+		if resp != nil {
+			closeResponseBody(resp)
+		}
+		return false, d, nil, e
+	}
+	switch resp.StatusCode {
+	case 200:
+		return true, d, resp, nil
+	case 404:
+		return false, d, resp, nil
+	default:
+		return false, d, nil, generateUnexpectedResponseCodeError(resp)
+	}
+}

A lib/cleanhttp/cleanhttp.go

@@ -0,0 +1,60 @@ 
+// Copyright (c) HashiCorp, Inc.
+// SPDX-License-Identifier: MPL-2.0
+
+package cleanhttp
+
+import (
+	"net"
+	"net/http"
+	"runtime"
+	"time"
+)
+
+// DefaultTransport returns a new http.Transport with similar default values to
+// http.DefaultTransport, but with idle connections and keepalives disabled.
+func DefaultTransport() *http.Transport {
+	transport := DefaultPooledTransport()
+	transport.DisableKeepAlives = true
+	transport.MaxIdleConnsPerHost = -1
+	return transport
+}
+
+// DefaultPooledTransport returns a new http.Transport with similar default
+// values to http.DefaultTransport. Do not use this for transient transports as
+// it can leak file descriptors over time. Only use this for transports that
+// will be re-used for the same host(s).
+func DefaultPooledTransport() *http.Transport {
+	transport := &http.Transport{
+		Proxy: http.ProxyFromEnvironment,
+		DialContext: (&net.Dialer{
+			Timeout:   30 * time.Second,
+			KeepAlive: 30 * time.Second,
+			DualStack: true,
+		}).DialContext,
+		MaxIdleConns:          100,
+		IdleConnTimeout:       90 * time.Second,
+		ExpectContinueTimeout: 1 * time.Second,
+		ForceAttemptHTTP2:     true,
+		MaxIdleConnsPerHost:   runtime.GOMAXPROCS(0) + 1,
+	}
+	return transport
+}
+
+// DefaultClient returns a new http.Client with similar default values to
+// http.Client, but with a non-shared Transport, idle connections disabled, and
+// keepalives disabled.
+func DefaultClient() *http.Client {
+	return &http.Client{
+		Transport: DefaultTransport(),
+	}
+}
+
+// DefaultPooledClient returns a new http.Client with similar default values to
+// http.Client, but with a shared Transport. Do not use this function for
+// transient clients as it can leak file descriptors over time. Only use this
+// for clients that will be re-used for the same host(s).
+func DefaultPooledClient() *http.Client {
+	return &http.Client{
+		Transport: DefaultPooledTransport(),
+	}
+}