github.com/hugh712/snapd@v0.0.0-20200910133618-1a99902bd583/overlord/snapstate/catalogrefresh.go (about)

     1  // -*- Mode: Go; indent-tabs-mode: t -*-
     2  
     3  /*
     4   * Copyright (C) 2017 Canonical Ltd
     5   *
     6   * This program is free software: you can redistribute it and/or modify
     7   * it under the terms of the GNU General Public License version 3 as
     8   * published by the Free Software Foundation.
     9   *
    10   * This program is distributed in the hope that it will be useful,
    11   * but WITHOUT ANY WARRANTY; without even the implied warranty of
    12   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    13   * GNU General Public License for more details.
    14   *
    15   * You should have received a copy of the GNU General Public License
    16   * along with this program.  If not, see <http://www.gnu.org/licenses/>.
    17   *
    18   */
    19  
    20  package snapstate
    21  
    22  import (
    23  	"fmt"
    24  	"os"
    25  	"sort"
    26  	"strings"
    27  	"time"
    28  
    29  	"github.com/snapcore/snapd/advisor"
    30  	"github.com/snapcore/snapd/dirs"
    31  	"github.com/snapcore/snapd/logger"
    32  	"github.com/snapcore/snapd/osutil"
    33  	"github.com/snapcore/snapd/overlord/auth"
    34  	"github.com/snapcore/snapd/overlord/state"
    35  	"github.com/snapcore/snapd/randutil"
    36  	"github.com/snapcore/snapd/store"
    37  	"github.com/snapcore/snapd/timings"
    38  )
    39  
    40  var (
    41  	catalogRefreshDelayBase      = 24 * time.Hour
    42  	catalogRefreshDelayWithDelta = 24*time.Hour + 1 + randutil.RandomDuration(6*time.Hour)
    43  )
    44  
    45  type catalogRefresh struct {
    46  	state *state.State
    47  
    48  	nextCatalogRefresh time.Time
    49  }
    50  
    51  func newCatalogRefresh(st *state.State) *catalogRefresh {
    52  	return &catalogRefresh{state: st}
    53  }
    54  
    55  // Ensure will ensure that the catalog refresh happens
    56  func (r *catalogRefresh) Ensure() error {
    57  	r.state.Lock()
    58  	defer r.state.Unlock()
    59  
    60  	// sneakily don't do anything if in testing
    61  	if CanAutoRefresh == nil {
    62  		return nil
    63  	}
    64  
    65  	// if system is not seeded yet, it is first boot situation
    66  	// do not bother refreshing catalog, snap list is empty anyway
    67  	// beside there is high change device has no internet
    68  	var seeded bool
    69  	err := r.state.Get("seeded", &seeded)
    70  	if err == state.ErrNoState || !seeded {
    71  		logger.Debugf("CatalogRefresh:Ensure: skipping refresh, system is not seeded yet")
    72  		// not seeded yet
    73  		return nil
    74  	}
    75  
    76  	now := time.Now()
    77  	delay := catalogRefreshDelayBase
    78  	if r.nextCatalogRefresh.IsZero() {
    79  		// try to use the timestamp on the sections file
    80  		if st, err := os.Stat(dirs.SnapNamesFile); err == nil && st.ModTime().Before(now) {
    81  			// add the delay with the delta so we spread the load a bit
    82  			r.nextCatalogRefresh = st.ModTime().Add(catalogRefreshDelayWithDelta)
    83  		} else {
    84  			// first time scheduling, add the delta
    85  			delay = catalogRefreshDelayWithDelta
    86  		}
    87  	}
    88  
    89  	theStore := Store(r.state, nil)
    90  	needsRefresh := r.nextCatalogRefresh.IsZero() || r.nextCatalogRefresh.Before(now)
    91  
    92  	if !needsRefresh {
    93  		return nil
    94  	}
    95  
    96  	next := now.Add(delay)
    97  	// catalog refresh does not carry on trying on error
    98  	r.nextCatalogRefresh = next
    99  
   100  	logger.Debugf("Catalog refresh starting now; next scheduled for %s.", next)
   101  
   102  	err = refreshCatalogs(r.state, theStore)
   103  	switch err {
   104  	case nil:
   105  		logger.Debugf("Catalog refresh succeeded.")
   106  	case store.ErrTooManyRequests:
   107  		logger.Debugf("Catalog refresh postponed.")
   108  		err = nil
   109  	default:
   110  		logger.Debugf("Catalog refresh failed: %v.", err)
   111  	}
   112  	return err
   113  }
   114  
   115  var newCmdDB = advisor.Create
   116  
   117  func refreshCatalogs(st *state.State, theStore StoreService) error {
   118  	st.Unlock()
   119  	defer st.Lock()
   120  
   121  	perfTimings := timings.New(map[string]string{"ensure": "refresh-catalogs"})
   122  
   123  	if err := os.MkdirAll(dirs.SnapCacheDir, 0755); err != nil {
   124  		return fmt.Errorf("cannot create directory %q: %v", dirs.SnapCacheDir, err)
   125  	}
   126  
   127  	var sections []string
   128  	var err error
   129  	timings.Run(perfTimings, "get-sections", "query store for sections", func(tm timings.Measurer) {
   130  		sections, err = theStore.Sections(auth.EnsureContextTODO(), nil)
   131  	})
   132  	if err != nil {
   133  		return err
   134  	}
   135  	sort.Strings(sections)
   136  	if err := osutil.AtomicWriteFile(dirs.SnapSectionsFile, []byte(strings.Join(sections, "\n")), 0644, 0); err != nil {
   137  		return err
   138  	}
   139  
   140  	namesFile, err := osutil.NewAtomicFile(dirs.SnapNamesFile, 0644, 0, osutil.NoChown, osutil.NoChown)
   141  	if err != nil {
   142  		return err
   143  	}
   144  	defer namesFile.Cancel()
   145  
   146  	cmdDB, err := newCmdDB()
   147  	if err != nil {
   148  		return err
   149  	}
   150  
   151  	// if all goes well we'll Commit() making this a NOP:
   152  	defer cmdDB.Rollback()
   153  
   154  	timings.Run(perfTimings, "write-catalogs", "query store for catalogs", func(tm timings.Measurer) {
   155  		err = theStore.WriteCatalogs(auth.EnsureContextTODO(), namesFile, cmdDB)
   156  	})
   157  	if err != nil {
   158  		return err
   159  	}
   160  
   161  	err1 := namesFile.Commit()
   162  	err2 := cmdDB.Commit()
   163  
   164  	if err2 != nil {
   165  		return err2
   166  	}
   167  
   168  	st.Lock()
   169  	perfTimings.Save(st)
   170  	st.Unlock()
   171  
   172  	return err1
   173  }