mirror of https://github.com/portainer/portainer
54 lines
1.7 KiB
Go
54 lines
1.7 KiB
Go
package offlinegate
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import (
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"net/http"
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"strings"
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"time"
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httperror "github.com/portainer/portainer/pkg/libhttp/error"
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"github.com/rs/zerolog/log"
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lock "github.com/viney-shih/go-lock"
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)
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// OfflineGate is an entity that works similar to a mutex with signaling
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// Only the caller that has Locked a gate can unlock it, otherwise it will be blocked with a call to Lock.
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// Gate provides a passthrough http middleware that will wait for a locked gate to be unlocked.
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// For safety reasons, the middleware will timeout
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type OfflineGate struct {
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lock *lock.CASMutex
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}
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// NewOfflineGate creates a new gate
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func NewOfflineGate() *OfflineGate {
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return &OfflineGate{
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lock: lock.NewCASMutex(),
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}
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}
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// Lock locks readonly gate and returns a function to unlock
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func (o *OfflineGate) Lock() func() {
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o.lock.Lock()
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return o.lock.Unlock
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}
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// WaitingMiddleware returns an http handler that waits for the gate to be unlocked before continuing
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func (o *OfflineGate) WaitingMiddleware(timeout time.Duration, next http.Handler) http.Handler {
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return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
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if r.Method == "GET" || r.Method == "HEAD" || r.Method == "OPTIONS" || strings.HasPrefix(r.URL.Path, "/api/backup") || strings.HasPrefix(r.URL.Path, "/api/restore") {
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next.ServeHTTP(w, r)
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return
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}
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if !o.lock.RTryLockWithTimeout(timeout) {
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log.Error().Str("url", r.URL.Path).Msg("request timed out while waiting for the backup process to finish")
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httperror.WriteError(w, http.StatusRequestTimeout, "Request timed out while waiting for the backup process to finish", http.ErrHandlerTimeout)
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return
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}
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defer o.lock.RUnlock()
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next.ServeHTTP(w, r)
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})
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}
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