README
¶
instrumented_http
A Go http.RoundTripper that exports request statistics via Prometheus.
Example
Transparently inject instrumented_http into any http.Client or http.RoundTripper and get metrics about all requests made.
$ curl -Ss 127.0.0.1:9099/metrics | grep http
http_request_duration_seconds{handler="instrumented_http",host="my-cluster.example.org",method="GET",path="pods",query="",scheme="https",status="200",quantile="0.5"} 0.83626
http_request_duration_seconds{handler="instrumented_http",host="my-cluster.example.org",method="GET",path="pods",query="",scheme="https",status="200",quantile="0.9"} 0.736648
http_request_duration_seconds{handler="instrumented_http",host="my-cluster.example.org",method="GET",path="pods",query="",scheme="https",status="200",quantile="0.99"} 0.736648
http_request_duration_seconds_sum{handler="instrumented_http",host="my-cluster.example.org",method="GET",path="pods",query="",scheme="https",status="200"} 0.820274243
http_request_duration_seconds_count{handler="instrumented_http",host="my-cluster.example.org",method="GET",path="pods",query="",scheme="https",status="200"} 2
Usage
Browse the examples directory to see how instrumented_http works with:
- http.DefaultClient: examples/default-client
- a custom http.Transport: examples/custom-transport
- the Google CloudDNS client: examples/googledns
- the AWS Route53 client: examples/route53
- the Kubernetes client: examples/kubernetes
- Resty: examples/resty
- Sling: examples/sling
- Gentleman: examples/gentleman
Documentation
¶
Overview ¶
Package instrumented_http provides a drop-in metrics-enabled replacement for any http.Client or http.RoundTripper.
Index ¶
Constants ¶
const (
BogusStatusCode = 999
)
Variables ¶
var (
// RequestDurationSeconds is a Prometheus summary to collect request times.
RequestDurationSeconds = prometheus.NewSummaryVec(
prometheus.SummaryOpts{
Name: "request_duration_seconds",
Help: "The HTTP request latencies in seconds.",
Subsystem: "http",
ConstLabels: prometheus.Labels{"handler": handlerName},
Objectives: map[float64]float64{0.5: 0.05, 0.9: 0.01, 0.99: 0.001},
},
[]string{"scheme", "host", "path", "query", "method", "status"},
)
// EliminatingProcessor is a callback that returns a blank string on any input.
EliminatingProcessor = func(_ string) string { return "" }
// IdentityProcessor is callback that returns whatever is passed to it.
IdentityProcessor = func(input string) string { return input }
// LastPathElementProcessor is callback that returns the last element of a URL path.
LastPathElementProcessor = func(path string) string {
parts := strings.Split(path, "/")
return parts[len(parts)-1]
}
// IntToStringProcessor converts an integer value to its string representation.
IntToStringProcessor = func(input int) string { return fmt.Sprintf("%d", input) }
// ServerErrorCodeProcessor exports all failed responses (5xx, timeouts, ...) as status=failure
ServerErrorCodeProcessor = func(code int) string {
if code >= http.StatusInternalServerError {
return "failure"
}
return "success"
}
)
Functions ¶
func NewClient ¶
func NewClient(next *http.Client, cbs *Callbacks) *http.Client
NewClient takes a *http.Client and returns a *http.Client that has its RoundTripper wrapped with instrumentation. Optionally, It can receive a collection of callbacks that process request path and query into a suitable label value.
func NewTransport ¶
func NewTransport(next http.RoundTripper, cbs *Callbacks) http.RoundTripper
NewTransport takes a http.RoundTripper, wraps it with instrumentation and returns it as a new http.RoundTripper. Optionally, It can receive a collection of callbacks that process request path and query into a suitable label value.
Types ¶
type Callbacks ¶
type Callbacks struct {
PathProcessor func(string) string
QueryProcessor func(string) string
CodeProcessor func(int) string
}
Callbacks is a collection of callbacks passed to Transport.
Source Files
Directories