зеркало из https://github.com/github/vitess-gh.git
servenv: Framework to display information about the running process at /debug/status.
This commit is contained in:
Ryszard Szopa
Родитель
fa7051848f
Коммит
2d53c68b1a
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@ -0,0 +1,173 @@
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package servenv
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import (
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"bytes"
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"fmt"
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"html"
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"html/template"
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"io"
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"net/http"
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"os"
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"path/filepath"
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"sync"
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"time"
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log "github.com/golang/glog"
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)
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var (
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binaryName = filepath.Base(os.Args[0])
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hostname string
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serverStart = time.Now()
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statusMu sync.RWMutex
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statusSections []section
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statusTmpl = template.Must(reparse(nil))
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statusFuncMap = make(template.FuncMap)
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)
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type section struct {
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Banner string
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Fragment string
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F func() interface{}
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}
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// AddStatusFuncs merges the provided functions into the set of
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// functions used to render /debug/status. Call this before AddStatusPart
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// if your template requires custom functions.
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func AddStatusFuncs(fmap template.FuncMap) {
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statusMu.Lock()
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defer statusMu.Unlock()
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for name, fun := range fmap {
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if _, ok := statusFuncMap[name]; ok {
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panic("duplicate status func registered: " + name)
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}
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statusFuncMap[name] = fun
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}
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}
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var statusHTML = `<!DOCTYPE html>
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<html>
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<head>
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<title>Status for {{.BinaryName}}</title>
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<style>
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body {
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font-family: sans-serif;
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}
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h1 {
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clear: both;
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width: 100%;
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text-align: center;
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font-size: 120%;
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background: #eef;
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}
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.lefthand {
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float: left;
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width: 80%;
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}
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.righthand {
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text-align: right;
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}
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</style>
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</head>
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<h1>Status for {{.BinaryName}}</h1>
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<div>
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<div class=lefthand>
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Started: {{.StartTime}}<br>
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</div>
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<div class=righthand>
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Running on {{.Hostname}}<br>
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View <a href=/debug/vars>variables</a>,
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<a href=/debug/pprof>debugging profiles</a>,
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</div>
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</div>`
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func reparse(sections []section) (*template.Template, error) {
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var buf bytes.Buffer
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io.WriteString(&buf, `{{define "status"}}`)
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io.WriteString(&buf, statusHTML)
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for i, sec := range sections {
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fmt.Fprintf(&buf, "<h1>%s</h1>\n", html.EscapeString(sec.Banner))
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fmt.Fprintf(&buf, "{{$sec := index .Sections %d}}\n", i)
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fmt.Fprintf(&buf, `{{template "sec-%d" call $sec.F}}`+"\n", i)
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}
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fmt.Fprintf(&buf, `</html>`)
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io.WriteString(&buf, "{{end}}\n")
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for i, sec := range sections {
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fmt.Fprintf(&buf, `{{define "sec-%d"}}%s{{end}}\n`, i, sec.Fragment)
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}
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return template.New("").Funcs(statusFuncMap).Parse(buf.String())
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}
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// AddStatusPart adds a new section to status. frag is used as a
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// subtemplate of the template used to render /debug/status, and will
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// be executed using the value of invoking f at the time of the
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// /debug/status request. frag is parsed and executed with the
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// html/template package. Functions registered with AddStatusFuncs
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// may be used in the template.
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func AddStatusPart(banner, frag string, f func() interface{}) {
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statusMu.Lock()
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defer statusMu.Unlock()
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secs := append(statusSections, section{
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Banner: banner,
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Fragment: frag,
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F: f,
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})
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var err error
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statusTmpl, err = reparse(secs)
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if err != nil {
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secs[len(secs)-1] = section{
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Banner: banner,
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Fragment: "<code>bad statusz template: {{.}}</code>",
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F: func() interface{} { return err },
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}
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}
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statusTmpl, _ = reparse(secs)
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statusSections = secs
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}
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// AddStatusSection registers a function that generates extra
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// information for /debug/status. If banner is not empty, it will be
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// used as a header before the information. If more complex output
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// than a simple string is required use AddStatusPart instead.
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func AddStatusSection(banner string, f func() string) {
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AddStatusPart(banner, `{{.}}`, func() interface{} { return f() })
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}
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func statusHandler(w http.ResponseWriter, r *http.Request) {
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statusMu.Lock()
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defer statusMu.Unlock()
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data := struct {
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Sections []section
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BinaryName string
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Hostname string
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StartTime string
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}{
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Sections: statusSections,
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BinaryName: binaryName,
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Hostname: hostname,
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StartTime: serverStart.Format(time.RFC1123),
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}
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if err := statusTmpl.ExecuteTemplate(w, "status", data); err != nil {
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log.Errorf("servenv: couldn't execute template: %v", err)
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}
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}
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func init() {
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var err error
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hostname, err = os.Hostname()
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if err != nil {
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log.Fatalf("os.Hostname: %v", err)
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}
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http.HandleFunc("/debug/status", statusHandler)
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}
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@ -0,0 +1,54 @@
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package servenv
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import (
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"html/template"
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"io/ioutil"
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"net/http"
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"net/http/httptest"
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"regexp"
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"strings"
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"testing"
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)
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func init() {
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AddStatusFuncs(
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template.FuncMap{
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"to_upper": strings.ToUpper,
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})
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AddStatusPart("test_part", `{{ to_upper . }}`, func() interface{} {
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return "this should be uppercase"
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})
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AddStatusSection("test_section", func() string {
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return "this is a section"
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})
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}
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func TestStatus(t *testing.T) {
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server := httptest.NewServer(nil)
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defer server.Close()
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resp, err := http.Get(server.URL + "/debug/status")
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if err != nil {
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t.Fatalf("http.Get: %v", 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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t.Fatalf("ioutil.ReadAll: %v", err)
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}
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cases := []string{
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`h1.*test_part.*/h1`,
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`THIS SHOULD BE UPPERCASE`,
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`h1.*test_section.*/h1`,
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}
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for _, cas := range cases {
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if !regexp.MustCompile(cas).Match(body) {
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t.Errorf("failed matching: %q", cas)
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}
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}
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t.Logf("body: \n%s", body)
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}
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