63 lines
1.4 KiB
Go
63 lines
1.4 KiB
Go
// Package expvarhandler provides fasthttp-compatible request handler
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// serving expvars.
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package expvarhandler
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import (
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"expvar"
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"fmt"
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"regexp"
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"github.com/valyala/fasthttp"
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)
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var (
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expvarHandlerCalls = expvar.NewInt("expvarHandlerCalls")
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expvarRegexpErrors = expvar.NewInt("expvarRegexpErrors")
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)
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// ExpvarHandler dumps json representation of expvars to http response.
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//
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// Expvars may be filtered by regexp provided via 'r' query argument.
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//
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// See https://golang.org/pkg/expvar/ for details.
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func ExpvarHandler(ctx *fasthttp.RequestCtx) {
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expvarHandlerCalls.Add(1)
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ctx.Response.Reset()
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r, err := getExpvarRegexp(ctx)
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if err != nil {
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expvarRegexpErrors.Add(1)
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fmt.Fprintf(ctx, "Error when obtaining expvar regexp: %s", err)
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ctx.SetStatusCode(fasthttp.StatusBadRequest)
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return
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}
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fmt.Fprintf(ctx, "{\n")
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first := true
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expvar.Do(func(kv expvar.KeyValue) {
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if !first {
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fmt.Fprintf(ctx, ",\n")
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}
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if r.MatchString(kv.Key) {
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first = false
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fmt.Fprintf(ctx, "\t%q: %s", kv.Key, kv.Value)
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}
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})
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fmt.Fprintf(ctx, "\n}\n")
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ctx.SetContentType("application/json; charset=utf-8")
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}
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func getExpvarRegexp(ctx *fasthttp.RequestCtx) (*regexp.Regexp, error) {
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r := string(ctx.QueryArgs().Peek("r"))
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if len(r) == 0 {
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r = "."
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}
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rr, err := regexp.Compile(r)
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if err != nil {
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return nil, fmt.Errorf("cannot parse r=%q: %s", r, err)
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}
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return rr, nil
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}
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