package api import ( "bytes" "encoding/json" "fmt" "io" "net/http" "net/url" "strconv" "time" ) // QueryOptions are used to parameterize a query type QueryOptions struct { // Providing a datacenter overwrites the DC provided // by the Config Datacenter string // AllowStale allows any Consul server (non-leader) to service // a read. This allows for lower latency and higher throughput AllowStale bool // RequireConsistent forces the read to be fully consistent. // This is more expensive but prevents ever performing a stale // read. RequireConsistent bool // WaitIndex is used to enable a blocking query. Waits // until the timeout or the next index is reached WaitIndex uint64 // WaitTime is used to bound the duration of a wait. // Defaults to that of the Config, but can be overriden. WaitTime time.Duration // Token is used to provide a per-request ACL token // which overrides the agent's default token. Token string } // WriteOptions are used to parameterize a write type WriteOptions struct { // Providing a datacenter overwrites the DC provided // by the Config Datacenter string // Token is used to provide a per-request ACL token // which overrides the agent's default token. Token string } // 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 // Time of last contact from the leader for the // server servicing the request LastContact time.Duration // Is there a known leader KnownLeader bool // How long did the request take RequestTime time.Duration } // WriteMeta is used to return meta data about a write type WriteMeta struct { // How long did the request take RequestTime time.Duration } // HttpBasicAuth is used to authenticate http client with HTTP Basic Authentication type HttpBasicAuth struct { // Username to use for HTTP Basic Authentication Username string // Password to use for HTTP Basic Authentication Password string } // 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 // Datacenter to use. If not provided, the default agent datacenter is used. Datacenter string // HttpClient is the client to use. Default will be // used if not provided. HttpClient *http.Client // HttpAuth is the auth info to use for http access. HttpAuth *HttpBasicAuth // WaitTime limits how long a Watch will block. If not provided, // the agent default values will be used. WaitTime time.Duration // Token is used to provide a per-request ACL token // which overrides the agent's default token. Token string } // DefaultConfig returns a default configuration for the client func DefaultConfig() *Config { return &Config{ Address: "127.0.0.1:8500", Scheme: "http", HttpClient: http.DefaultClient, } } // Client provides a client to the Consul API type Client struct { config Config } // NewClient returns a new client func NewClient(config *Config) (*Client, error) { // bootstrap the config defConfig := DefaultConfig() if len(config.Address) == 0 { config.Address = defConfig.Address } if len(config.Scheme) == 0 { config.Scheme = defConfig.Scheme } if config.HttpClient == nil { config.HttpClient = defConfig.HttpClient } client := &Client{ config: *config, } return client, nil } // 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 obj interface{} } // setQueryOptions is used to annotate the request with // additional query options func (r *request) setQueryOptions(q *QueryOptions) { if q == nil { return } if q.Datacenter != "" { r.params.Set("dc", q.Datacenter) } if q.AllowStale { r.params.Set("stale", "") } if q.RequireConsistent { r.params.Set("consistent", "") } 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.Token != "" { r.params.Set("token", q.Token) } } // durToMsec converts a duration to a millisecond specified string func durToMsec(dur time.Duration) string { return fmt.Sprintf("%dms", dur/time.Millisecond) } // setWriteOptions is used to annotate the request with // additional write options func (r *request) setWriteOptions(q *WriteOptions) { if q == nil { return } if q.Datacenter != "" { r.params.Set("dc", q.Datacenter) } if q.Token != "" { r.params.Set("token", q.Token) } } // 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() // Get the url sring urlRaw := r.url.String() // Check if we should encode the body if r.body == nil && r.obj != nil { if b, err := encodeBody(r.obj); err != nil { return nil, err } else { r.body = b } } // Create the HTTP request req, err := http.NewRequest(r.method, urlRaw, r.body) // Setup auth if err == nil && r.config.HttpAuth != nil { req.SetBasicAuth(r.config.HttpAuth.Username, r.config.HttpAuth.Password) } return req, err } // 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), } if c.config.Datacenter != "" { r.params.Set("dc", c.config.Datacenter) } if c.config.WaitTime != 0 { r.params.Set("wait", durToMsec(r.config.WaitTime)) } if c.config.Token != "" { r.params.Set("token", r.config.Token) } 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.Now().Sub(start) return diff, resp, err } // 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 index, err := strconv.ParseUint(header.Get("X-Consul-Index"), 10, 64) if err != nil { return fmt.Errorf("Failed to parse X-Consul-Index: %v", err) } q.LastIndex = index // Parse the X-Consul-LastContact last, err := strconv.ParseUint(header.Get("X-Consul-LastContact"), 10, 64) if err != nil { return fmt.Errorf("Failed to parse X-Consul-LastContact: %v", err) } q.LastContact = time.Duration(last) * time.Millisecond // Parse the X-Consul-KnownLeader switch header.Get("X-Consul-KnownLeader") { case "true": q.KnownLeader = true default: q.KnownLeader = 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 { return d, resp, e } if resp.StatusCode != 200 { var buf bytes.Buffer io.Copy(&buf, resp.Body) return d, resp, fmt.Errorf("Unexpected response code: %d (%s)", resp.StatusCode, buf.Bytes()) } return d, resp, e }