144 lines
3.9 KiB
Go
144 lines
3.9 KiB
Go
package accesslog
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import (
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"context"
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"fmt"
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"net"
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"net/http"
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"net/url"
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"sync/atomic"
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"time"
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)
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type key string
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const (
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// DataTableKey is the key within the request context used to
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// store the Log Data Table
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DataTableKey key = "LogDataTable"
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)
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// LogHandler will write each request and its response to the access log.
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// It gets some information from the logInfoResponseWriter set up by previous middleware.
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// Note: Current implementation collects log data but does not have the facility to
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// write anywhere.
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type LogHandler struct {
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}
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// NewLogHandler creates a new LogHandler
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func NewLogHandler() *LogHandler {
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return &LogHandler{}
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}
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// GetLogDataTable gets the request context object that contains logging data. This accretes
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// data as the request passes through the middleware chain.
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func GetLogDataTable(req *http.Request) *LogData {
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return req.Context().Value(DataTableKey).(*LogData)
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}
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func (l *LogHandler) ServeHTTP(rw http.ResponseWriter, req *http.Request, next http.HandlerFunc) {
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now := time.Now().UTC()
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core := make(CoreLogData)
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logDataTable := &LogData{Core: core, Request: req.Header}
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core[StartUTC] = now
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core[StartLocal] = now.Local()
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reqWithDataTable := req.WithContext(context.WithValue(req.Context(), DataTableKey, logDataTable))
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var crr *captureRequestReader
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if req.Body != nil {
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crr = &captureRequestReader{source: req.Body, count: 0}
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reqWithDataTable.Body = crr
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}
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core[RequestCount] = nextRequestCount()
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if req.Host != "" {
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core[RequestAddr] = req.Host
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core[RequestHost], core[RequestPort] = silentSplitHostPort(req.Host)
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}
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// copy the URL without the scheme, hostname etc
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urlCopy := &url.URL{
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Path: req.URL.Path,
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RawPath: req.URL.RawPath,
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RawQuery: req.URL.RawQuery,
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ForceQuery: req.URL.ForceQuery,
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Fragment: req.URL.Fragment,
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}
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urlCopyString := urlCopy.String()
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core[RequestMethod] = req.Method
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core[RequestPath] = urlCopyString
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core[RequestProtocol] = req.Proto
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core[RequestLine] = fmt.Sprintf("%s %s %s", req.Method, urlCopyString, req.Proto)
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core[ClientAddr] = req.RemoteAddr
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core[ClientHost], core[ClientPort] = silentSplitHostPort(req.RemoteAddr)
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core[ClientUsername] = usernameIfPresent(req.URL)
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crw := &captureResponseWriter{rw: rw}
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next.ServeHTTP(crw, reqWithDataTable)
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logDataTable.DownstreamResponse = crw.Header()
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l.logTheRoundTrip(logDataTable, crr, crw)
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}
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// Close closes the Logger (i.e. the file etc).
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func (l *LogHandler) Close() error {
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return nil
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}
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func silentSplitHostPort(value string) (host string, port string) {
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host, port, err := net.SplitHostPort(value)
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if err != nil {
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return value, "-"
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}
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return host, port
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}
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func usernameIfPresent(theURL *url.URL) string {
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username := "-"
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if theURL.User != nil {
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if name := theURL.User.Username(); name != "" {
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username = name
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}
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}
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return username
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}
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// Logging handler to log frontend name, backend name, and elapsed time
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func (l *LogHandler) logTheRoundTrip(logDataTable *LogData, crr *captureRequestReader, crw *captureResponseWriter) {
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core := logDataTable.Core
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if crr != nil {
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core[RequestContentSize] = crr.count
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}
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core[DownstreamStatus] = crw.Status()
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core[DownstreamStatusLine] = fmt.Sprintf("%03d %s", crw.Status(), http.StatusText(crw.Status()))
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core[DownstreamContentSize] = crw.Size()
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if original, ok := core[OriginContentSize]; ok {
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o64 := original.(int64)
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if o64 != crw.Size() && 0 != crw.Size() {
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core[GzipRatio] = float64(o64) / float64(crw.Size())
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}
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}
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// n.b. take care to perform time arithmetic using UTC to avoid errors at DST boundaries
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total := time.Now().UTC().Sub(core[StartUTC].(time.Time))
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core[Duration] = total
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if origin, ok := core[OriginDuration]; ok {
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core[Overhead] = total - origin.(time.Duration)
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} else {
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core[Overhead] = total
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}
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}
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//-------------------------------------------------------------------------------------------------
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var requestCounter uint64 // Request ID
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func nextRequestCount() uint64 {
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return atomic.AddUint64(&requestCounter, 1)
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}
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