152 lines
3.7 KiB
Go
152 lines
3.7 KiB
Go
package circuitbreaker
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import (
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"context"
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"html/template"
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"net"
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"net/http"
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"path/filepath"
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"sync"
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"forge.cadoles.com/Cadoles/go-proxy"
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"forge.cadoles.com/Cadoles/go-proxy/wildcard"
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"forge.cadoles.com/cadoles/bouncer/internal/proxy/director"
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"forge.cadoles.com/cadoles/bouncer/internal/store"
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"github.com/Masterminds/sprig/v3"
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"github.com/pkg/errors"
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"gitlab.com/wpetit/goweb/logger"
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)
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const LayerType store.LayerType = "circuitbreaker"
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type Layer struct {
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templateDir string
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loadOnce sync.Once
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tmpl *template.Template
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}
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// LayerType implements director.MiddlewareLayer
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func (l *Layer) LayerType() store.LayerType {
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return LayerType
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}
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// Middleware implements director.MiddlewareLayer
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func (l *Layer) Middleware(layer *store.Layer) proxy.Middleware {
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return func(h http.Handler) http.Handler {
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fn := func(w http.ResponseWriter, r *http.Request) {
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ctx := r.Context()
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options, err := fromStoreOptions(layer.Options)
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if err != nil {
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logger.Error(ctx, "could not parse layer options", logger.E(errors.WithStack(err)))
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http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
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return
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}
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matches, err := l.matchAnyAuthorizedCIDRs(ctx, r.RemoteAddr, options.AuthorizedCIDRs)
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if err != nil {
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logger.Error(ctx, "could not match authorized cidrs", logger.E(errors.WithStack(err)))
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http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
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return
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}
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if matches {
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h.ServeHTTP(w, r)
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return
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}
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matches = wildcard.MatchAny(r.URL.String(), options.MatchURLs...)
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if !matches {
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h.ServeHTTP(w, r)
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return
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}
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l.renderCircuitBreakerPage(w, r, layer, options)
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}
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return http.HandlerFunc(fn)
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}
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}
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func (l *Layer) matchAnyAuthorizedCIDRs(ctx context.Context, remoteHostPort string, CIDRs []string) (bool, error) {
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remoteHost, _, err := net.SplitHostPort(remoteHostPort)
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if err != nil {
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return false, errors.WithStack(err)
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}
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remoteAddr := net.ParseIP(remoteHost)
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if remoteAddr == nil {
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return false, errors.Errorf("remote host '%s' is not a valid ip address", remoteHost)
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}
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for _, rawCIDR := range CIDRs {
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_, net, err := net.ParseCIDR(rawCIDR)
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if err != nil {
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return false, errors.WithStack(err)
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}
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match := net.Contains(remoteAddr)
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if !match {
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continue
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}
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return true, nil
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}
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logger.Debug(ctx, "comparing remote host with authorized cidrs", logger.F("remoteAddr", remoteAddr))
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return false, nil
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}
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func (l *Layer) renderCircuitBreakerPage(w http.ResponseWriter, r *http.Request, layer *store.Layer, options *LayerOptions) {
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ctx := r.Context()
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pattern := filepath.Join(l.templateDir, "*.gohtml")
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logger.Info(ctx, "loading circuit breaker page templates", logger.F("pattern", pattern))
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tmpl, err := template.New("").Funcs(sprig.FuncMap()).ParseGlob(pattern)
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if err != nil {
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logger.Error(ctx, "could not load circuit breaker templates", logger.E(errors.WithStack(err)))
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http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
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return
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}
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templateData := struct {
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Layer *store.Layer
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LayerOptions *LayerOptions
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}{
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Layer: layer,
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LayerOptions: options,
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}
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w.Header().Add("Cache-Control", "no-cache")
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w.WriteHeader(http.StatusOK)
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if err := tmpl.ExecuteTemplate(w, options.TemplateBlock, templateData); err != nil {
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logger.Error(ctx, "could not render circuit breaker page", logger.E(errors.WithStack(err)))
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http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
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return
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}
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}
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func New(funcs ...OptionFunc) *Layer {
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opts := defaultOptions()
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for _, fn := range funcs {
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fn(opts)
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}
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return &Layer{
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templateDir: opts.TemplateDir,
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}
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}
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var _ director.MiddlewareLayer = &Layer{}
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