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76af9ba53d
This implements a new debug/trace infrastructure based on a slightly
hacked up logger. Instead of the traditional "if debug { ... }" I've
rewritten the logger to have no-op Debugln and Debugf, unless debugging
has been enabled for a given "facility". The "facility" is just a
string, typically a package name.
This will be slightly slower than before; but not that much as it's
mostly a function call that returns immediately. For the cases where it
matters (the Debugln takes a hex.Dump() of something for example, and
it's not in a very occasional "if err != nil" branch) there is an
l.ShouldDebug(facility) that is fast enough to be used like the old "if
debug".
The point of all this is that we can now toggle debugging for the
various packages on and off at runtime. There's a new method
/rest/system/debug that can be POSTed a set of facilities to enable and
disable debug for, or GET from to get a list of facilities with
descriptions and their current debug status.
Similarly a /rest/system/log?since=... can grab the latest log entries,
up to 250 of them (hardcoded constant in main.go) plus the initial few.
Not implemented in this commit (but planned) is a simple debug GUI
available on /debug that shows the current log in an easily pasteable
format and has checkboxes to enable the various debug facilities.
The debug instructions to a user then becomes "visit this URL, check
these boxes, reproduce your problem, copy and paste the log". The actual
log viewer on the hypothetical /debug URL can poll regularly for new log
entries and this bypass the 250 line limit.
The existing STTRACE=foo variable is still obeyed and just sets the
start state of the system.
79 lines
2.4 KiB
Go
79 lines
2.4 KiB
Go
// Copyright (C) 2015 The Syncthing Authors.
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//
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// This Source Code Form is subject to the terms of the Mozilla Public
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// License, v. 2.0. If a copy of the MPL was not distributed with this file,
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// You can obtain one at http://mozilla.org/MPL/2.0/.
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package db
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import (
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"fmt"
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"time"
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"github.com/syndtr/goleveldb/leveldb"
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)
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// This type encapsulates a repository of mtimes for platforms where file mtimes
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// can't be set to arbitrary values. For this to work, we need to store both
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// the mtime we tried to set (the "actual" mtime) as well as the mtime the file
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// has when we're done touching it (the "disk" mtime) so that we can tell if it
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// was changed. So in GetMtime(), it's not sufficient that the record exists --
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// the argument must also equal the "disk" mtime in the record, otherwise it's
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// been touched locally and the "disk" mtime is actually correct.
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type VirtualMtimeRepo struct {
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ns *NamespacedKV
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}
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func NewVirtualMtimeRepo(ldb *leveldb.DB, folder string) *VirtualMtimeRepo {
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prefix := string(KeyTypeVirtualMtime) + folder
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return &VirtualMtimeRepo{
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ns: NewNamespacedKV(ldb, prefix),
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}
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}
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func (r *VirtualMtimeRepo) UpdateMtime(path string, diskMtime, actualMtime time.Time) {
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l.Debugf("virtual mtime: storing values for path:%s disk:%v actual:%v", path, diskMtime, actualMtime)
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diskBytes, _ := diskMtime.MarshalBinary()
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actualBytes, _ := actualMtime.MarshalBinary()
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data := append(diskBytes, actualBytes...)
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r.ns.PutBytes(path, data)
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}
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func (r *VirtualMtimeRepo) GetMtime(path string, diskMtime time.Time) time.Time {
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data, exists := r.ns.Bytes(path)
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if !exists {
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// Absense of debug print is significant enough in itself here
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return diskMtime
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}
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var mtime time.Time
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if err := mtime.UnmarshalBinary(data[:len(data)/2]); err != nil {
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panic(fmt.Sprintf("Can't unmarshal stored mtime at path %s: %v", path, err))
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}
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if mtime.Equal(diskMtime) {
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if err := mtime.UnmarshalBinary(data[len(data)/2:]); err != nil {
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panic(fmt.Sprintf("Can't unmarshal stored mtime at path %s: %v", path, err))
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}
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l.Debugf("virtual mtime: return %v instead of %v for path: %s", mtime, diskMtime, path)
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return mtime
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}
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l.Debugf("virtual mtime: record exists, but mismatch inDisk: %v dbDisk: %v for path: %s", diskMtime, mtime, path)
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return diskMtime
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}
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func (r *VirtualMtimeRepo) DeleteMtime(path string) {
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r.ns.Delete(path)
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}
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func (r *VirtualMtimeRepo) Drop() {
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r.ns.Reset()
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}
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