Modifications to httpjson plugin
This commit is contained in:
Josh Palay
parent
fc8ef3bf3a
commit
52b8b1ec96
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@ -2,34 +2,69 @@ package httpjson
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import (
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"encoding/json"
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"errors"
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"fmt"
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"github.com/bitly/go-simplejson"
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"github.com/influxdb/telegraf/plugins"
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"io/ioutil"
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"net/http"
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"net/url"
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"strings"
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"sync"
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"github.com/influxdb/telegraf/plugins"
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)
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type HttpJson struct {
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Services []Service
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client HTTPClient
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}
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type Service struct {
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Name string
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Servers []string
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Measurements map[string]string
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Method string
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Foo string
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Parameters map[string]string
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}
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type HTTPClient interface {
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// Returns the result of an http request
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//
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// Parameters:
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// req: HTTP request object
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//
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// Returns:
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// http.Response: HTTP respons object
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// error : Any error that may have occurred
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MakeRequest(req *http.Request) (*http.Response, error)
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}
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type RealHTTPClient struct {
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client *http.Client
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}
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func (c RealHTTPClient) MakeRequest(req *http.Request) (*http.Response, error) {
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return c.client.Do(req)
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}
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var sampleConfig = `
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# stats url endpoint
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servers = ["http://localhost:5000"]
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# Specify services via an array of tables
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[[httpjson.services]]
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# a name for server(s)
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foo = "mycluster"
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# a name for the service being polled
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name = "webserver_stats"
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# HTTP method (GET or POST)
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method = "GET"
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# URL of each server in the service's cluster
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servers = [
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"http://localhost:9999/stats/",
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"http://localhost:9998/stats/",
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]
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# Map of key transforms # TODO describe
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[httpjson.measurements]
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stats_measurements_measurement = "my_measurement"
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# HTTP method to use (case-sensitive)
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method = "GET"
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# HTTP parameters (all values must be strings)
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[httpjson.services.parameters]
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event_type = "cpu_spike"
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threshold = "0.75"
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`
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func (h *HttpJson) SampleConfig() string {
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@ -40,71 +75,140 @@ func (h *HttpJson) Description() string {
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return "Read flattened metrics from one or more JSON HTTP endpoints"
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}
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// Gathers data for all servers.
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func (h *HttpJson) Gather(acc plugins.Accumulator) error {
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var wg sync.WaitGroup
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var outerr error
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totalServers := 0
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for _, service := range h.Services {
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totalServers += len(service.Servers)
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}
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errorChannel := make(chan error, totalServers)
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for _, server := range h.Servers {
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for _, service := range h.Services {
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for _, server := range service.Servers {
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wg.Add(1)
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go func(server string) {
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go func(service Service, server string) {
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defer wg.Done()
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outerr = h.gatherServer(server, acc)
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}(server)
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if err := h.gatherServer(acc, service, server); err != nil {
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errorChannel <- err
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}
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}(service, server)
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}
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}
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wg.Wait()
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close(errorChannel)
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return outerr
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// Get all errors and return them as one giant error
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errorStrings := []string{}
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for err := range errorChannel {
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errorStrings = append(errorStrings, err.Error())
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}
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if len(errorStrings) == 0 {
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return nil
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}
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return errors.New(strings.Join(errorStrings, "\n"))
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}
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func (h *HttpJson) gatherServer(url string, acc plugins.Accumulator) error {
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r, err := h.client.Get(url)
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// Gathers data from a particular server
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// Parameters:
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// acc : The telegraf Accumulator to use
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// serverURL: endpoint to send request to
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// service : the service being queried
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//
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// Returns:
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// error: Any error that may have occurred
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func (h *HttpJson) gatherServer(acc plugins.Accumulator, service Service, serverURL string) error {
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resp, err := h.sendRequest(service, serverURL)
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if err != nil {
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return err
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}
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if r.StatusCode != http.StatusOK {
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return fmt.Errorf("httpjson: server '%s' responded with status-code %d, expected %d", r.StatusCode, http.StatusOK)
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}
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response, err := simplejson.NewFromReader(r.Body)
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if err != nil {
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return err
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var jsonOut interface{}
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if err = json.Unmarshal([]byte(resp), &jsonOut); err != nil {
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return errors.New("Error decoding JSON response")
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}
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tags := map[string]string{
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"server": url,
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"server": serverURL,
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}
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return parseResponse(acc, h.Foo, tags, response.Interface(), h.Measurements)
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processResponse(acc, service.Name, tags, jsonOut)
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return nil
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}
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func parseResponse(acc plugins.Accumulator, prefix string, tags map[string]string, v interface{}, measurements map[string]string) error {
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// Sends an HTTP request to the server using the HttpJson object's HTTPClient
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// Parameters:
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// serverURL: endpoint to send request to
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//
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// Returns:
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// string: body of the response
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// error : Any error that may have occurred
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func (h *HttpJson) sendRequest(service Service, serverURL string) (string, error) {
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// Prepare URL
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requestURL, err := url.Parse(serverURL)
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if err != nil {
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return "", fmt.Errorf("Invalid server URL \"%s\"", serverURL)
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}
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params := url.Values{}
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for k, v := range service.Parameters {
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params.Add(k, v)
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}
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requestURL.RawQuery = params.Encode()
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// Create + send request
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req, err := http.NewRequest(service.Method, requestURL.String(), nil)
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if err != nil {
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return "", err
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}
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resp, err := h.client.MakeRequest(req)
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if err != nil {
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return "", err
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}
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defer resp.Body.Close()
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body, err := ioutil.ReadAll(resp.Body)
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if err != nil {
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return string(body), err
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}
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// Process response
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if resp.StatusCode != http.StatusOK {
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err = fmt.Errorf("Response from url \"%s\" has status code %d (%s), expected %d (%s)",
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requestURL.String(),
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resp.StatusCode,
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http.StatusText(resp.StatusCode),
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http.StatusOK,
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http.StatusText(http.StatusOK))
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return string(body), err
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}
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return string(body), err
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}
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// Flattens the map generated from the JSON object and stores its float values using a
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// plugins.Accumulator. It ignores any non-float values.
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// Parameters:
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// acc: the Accumulator to use
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// prefix: What the name of the measurement name should be prefixed by.
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// tags: telegraf tags to
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func processResponse(acc plugins.Accumulator, prefix string, tags map[string]string, v interface{}) {
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switch t := v.(type) {
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case map[string]interface{}:
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for k, v := range t {
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if err := parseResponse(acc, prefix+"_"+k, tags, v, measurements); err != nil {
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return err
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processResponse(acc, prefix+"_"+k, tags, v)
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}
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case float64:
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acc.Add(prefix, v, tags)
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}
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case json.Number:
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if transform, ok := measurements[prefix]; ok {
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prefix = transform
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}
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acc.Add(prefix, t, tags)
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case bool, string, []interface{}:
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// ignored types
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return nil
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default:
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return fmt.Errorf("httpjson: got unexpected type %T with value %v (%s)", t, v, prefix)
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}
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return nil
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}
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func init() {
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plugins.Add("httpjson", func() plugins.Plugin {
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return &HttpJson{client: http.DefaultClient}
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return &HttpJson{client: RealHTTPClient{client: &http.Client{}}}
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})
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}
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@ -0,0 +1,187 @@
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package httpjson
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import (
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"fmt"
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"io/ioutil"
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"net/http"
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"strings"
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"testing"
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"github.com/influxdb/telegraf/testutil"
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"github.com/stretchr/testify/assert"
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"github.com/stretchr/testify/require"
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)
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const validJSON = `
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{
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"parent": {
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"child": 3,
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"ignored_child": "hi"
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},
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"ignored_null": null,
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"integer": 4,
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"ignored_list": [3, 4],
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"ignored_parent": {
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"another_ignored_list": [4],
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"another_ignored_null": null,
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"ignored_string": "hello, world!"
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}
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}`
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const invalidJSON = "I don't think this is JSON"
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const empty = ""
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type mockHTTPClient struct {
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responseBody string
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statusCode int
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}
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// Mock implementation of MakeRequest. Usually returns an http.Response with
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// hard-coded responseBody and statusCode. However, if the request uses a
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// nonstandard method, it uses status code 405 (method not allowed)
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func (c mockHTTPClient) MakeRequest(req *http.Request) (*http.Response, error) {
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resp := http.Response{}
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resp.StatusCode = c.statusCode
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// basic error checking on request method
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allowedMethods := []string{"GET", "HEAD", "POST", "PUT", "DELETE", "TRACE", "CONNECT"}
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methodValid := false
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for _, method := range allowedMethods {
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if req.Method == method {
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methodValid = true
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break
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}
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}
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if !methodValid {
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resp.StatusCode = 405 // Method not allowed
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}
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resp.Body = ioutil.NopCloser(strings.NewReader(c.responseBody))
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return &resp, nil
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}
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// Generates a pointer to an HttpJson object that uses a mock HTTP client.
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// Parameters:
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// response : Body of the response that the mock HTTP client should return
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// statusCode: HTTP status code the mock HTTP client should return
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//
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// Returns:
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// *HttpJson: Pointer to an HttpJson object that uses the generated mock HTTP client
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func genMockHttpJson(response string, statusCode int) *HttpJson {
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return &HttpJson{
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client: mockHTTPClient{responseBody: response, statusCode: statusCode},
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Services: []Service{
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Service{
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Servers: []string{
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"http://server1.example.com/metrics/",
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"http://server2.example.com/metrics/",
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},
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Name: "my_webapp",
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Method: "GET",
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Parameters: map[string]string{
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"httpParam1": "12",
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"httpParam2": "the second parameter",
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},
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},
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Service{
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Servers: []string{
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"http://server1.example.com/metrics/",
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"http://server2.example.com/metrics/",
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},
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Name: "other_webapp",
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Method: "POST",
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Parameters: map[string]string{
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"httpParam1": "12",
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"httpParam2": "the second parameter",
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},
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},
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},
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}
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}
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// Test that the proper values are ignored or collected
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func TestHttpJson200(t *testing.T) {
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httpjson := genMockHttpJson(validJSON, 200)
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var acc testutil.Accumulator
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err := httpjson.Gather(&acc)
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require.NoError(t, err)
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assert.Equal(t, 8, len(acc.Points))
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for _, service := range httpjson.Services {
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for _, srv := range service.Servers {
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require.NoError(t,
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acc.ValidateTaggedValue(
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fmt.Sprintf("%s_parent_child", service.Name),
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3.0,
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map[string]string{"server": srv},
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),
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)
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require.NoError(t,
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acc.ValidateTaggedValue(
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fmt.Sprintf("%s_integer", service.Name),
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4.0,
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map[string]string{"server": srv},
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),
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)
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}
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}
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}
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// Test response to HTTP 500
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func TestHttpJson500(t *testing.T) {
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httpjson := genMockHttpJson(validJSON, 500)
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var acc testutil.Accumulator
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err := httpjson.Gather(&acc)
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assert.NotNil(t, err)
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// 4 error lines for (2 urls) * (2 services)
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assert.Equal(t, len(strings.Split(err.Error(), "\n")), 4)
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assert.Equal(t, 0, len(acc.Points))
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}
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// Test response to HTTP 405
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func TestHttpJsonBadMethod(t *testing.T) {
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httpjson := genMockHttpJson(validJSON, 200)
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httpjson.Services[0].Method = "NOT_A_REAL_METHOD"
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var acc testutil.Accumulator
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err := httpjson.Gather(&acc)
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assert.NotNil(t, err)
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// 2 error lines for (2 urls) * (1 falied service)
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assert.Equal(t, len(strings.Split(err.Error(), "\n")), 2)
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// (2 measurements) * (2 servers) * (1 successful service)
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assert.Equal(t, 4, len(acc.Points))
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}
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// Test response to malformed JSON
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func TestHttpJsonBadJson(t *testing.T) {
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httpjson := genMockHttpJson(invalidJSON, 200)
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var acc testutil.Accumulator
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err := httpjson.Gather(&acc)
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assert.NotNil(t, err)
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// 4 error lines for (2 urls) * (2 services)
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assert.Equal(t, len(strings.Split(err.Error(), "\n")), 4)
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assert.Equal(t, 0, len(acc.Points))
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}
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// Test response to empty string as response objectgT
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func TestHttpJsonEmptyResponse(t *testing.T) {
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httpjson := genMockHttpJson(empty, 200)
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var acc testutil.Accumulator
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err := httpjson.Gather(&acc)
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assert.NotNil(t, err)
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// 4 error lines for (2 urls) * (2 services)
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assert.Equal(t, len(strings.Split(err.Error(), "\n")), 4)
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assert.Equal(t, 0, len(acc.Points))
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}
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