package http import ( "bytes" "context" "encoding/json" "fmt" "net/http" "net/url" "strings" opentracing "github.com/opentracing/opentracing-go" "github.com/opentracing/opentracing-go/ext" ) // PostJSON performs a POST request with JSON on an internal HTTP API func PostJSON( ctx context.Context, span opentracing.Span, httpClient *http.Client, apiURL string, request, response interface{}, ) error { jsonBytes, err := json.Marshal(request) if err != nil { return err } parsedAPIURL, err := url.Parse(apiURL) if err != nil { return err } parsedAPIURL.Path = "/api/" + strings.TrimLeft(parsedAPIURL.Path, "/") apiURL = parsedAPIURL.String() req, err := http.NewRequest(http.MethodPost, apiURL, bytes.NewReader(jsonBytes)) if err != nil { return err } // Mark the span as being an RPC client. ext.SpanKindRPCClient.Set(span) carrier := opentracing.HTTPHeadersCarrier(req.Header) tracer := opentracing.GlobalTracer() if err = tracer.Inject(span.Context(), opentracing.HTTPHeaders, carrier); err != nil { return err } req.Header.Set("Content-Type", "application/json") res, err := httpClient.Do(req.WithContext(ctx)) if res != nil { defer (func() { err = res.Body.Close() })() } if err != nil { return err } if res.StatusCode != http.StatusOK { var errorBody struct { Message string `json:"message"` } if msgerr := json.NewDecoder(res.Body).Decode(&errorBody); msgerr == nil { return fmt.Errorf("api: %d from %s: %s", res.StatusCode, apiURL, errorBody.Message) } return fmt.Errorf("api: %d from %s", res.StatusCode, apiURL) } return json.NewDecoder(res.Body).Decode(response) }