CoCalc -- rolling_snapshots.coffee

Path: cocalc/src / smc-hub / rolling_snapshots.coffee
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###
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Create rolling snapshots of a given ZFS volume
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###
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fs          = require('fs')
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async       = require('async')
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winston     = require('winston')
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# Set the log level
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winston.remove(winston.transports.Console)
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winston.add(winston.transports.Console, {level: 'debug', timestamp:true, colorize:true})
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misc_node = require('smc-util-node/misc_node')
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misc      = require('smc-util/misc')
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{defaults, required} = misc
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list_snapshots = (filesystem, cb) ->
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    misc_node.execute_code
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        command : 'sudo'
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        args    : ['zfs', 'list', '-r', '-H', '-t', 'snapshot', filesystem]
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        cb      : (err, output) ->
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            if err
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                cb(err)
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            else
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                v = (misc.split(x)[0].split('@')[1] for x in output.stdout.split('\n') when x.trim())
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                v.sort()
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                cb(undefined, v)
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make_snapshot = (filesystem, snap, cb) ->
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    async.series([
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        (cb) ->
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            misc_node.execute_code
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                command : 'sudo'
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                args    : ['zfs', 'snapshot', "#{filesystem}@#{snap}"]
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                cb      : cb
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        (cb) ->
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            # read the directory to cause it to be mounted
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            fs.readdir("/#{filesystem}/.zfs/snapshot/#{snap}/", cb)
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    ], cb)
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delete_snapshot = (filesystem, snap, cb) ->
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    misc_node.execute_code
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        command : 'sudo'
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        args    : ['zfs', 'destroy', "#{filesystem}@#{snap}"]
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        cb      : cb
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INTERVALS =
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    five    : 5
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    hourly  : 60
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    daily   : 60*24
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    weekly  : 60*24*7
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    monthly : 60*24*7*4
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exports.update_snapshots = (opts) ->
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    opts = defaults opts,
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        filesystem : required
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        five       : 12*6   # 6 hours worth of five-minute snapshots to retain
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        hourly     : 24*7   # 1 week of hourly snapshots
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        daily      : 30     # 1 month of daily snapshots
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        weekly     : 8      # 2 months of weekly snapshots
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        monthly    : 6      # 6 months of monthly snapshots
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        cb         : undefined
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    dbg = (m) -> winston.debug("snapshot('#{opts.filesystem}'): #{m}")
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    dbg()
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    snapshots = undefined
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    to_create = []
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    to_delete = []
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    async.series([
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        (cb) ->
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            dbg("get list of all snapshots")
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            list_snapshots opts.filesystem, (err, x) ->
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                snapshots = x; cb(err)
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        (cb) ->
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            dbg("got #{snapshots.length} snapshots")
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            # determine which snapshots we need to make
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            now = new Date()
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            for name, interval of INTERVALS
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                if opts[name] <= 0 # not making any of these
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                    continue
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                # Is there a snapshot with the given name that is within the given
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                # interval of now?  If not, make snapshot.
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                v = (s for s in snapshots when misc.endswith(s, '-'+name))
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                if v.length > 0
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                    newest = v[v.length-1]
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                    t = misc.parse_bup_timestamp(newest)
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                    age_m = (now - t)/(60*1000)   # age in minutes since snapshot
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                else
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                    age_m = 999999999999  # 'infinite'
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                if age_m > interval
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                    # will make this snapshot
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                    to_create.push("#{misc.to_iso_path(now)}-#{name}")
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                # Are there too many snapshots of the given type?  If so, delete them
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                if v.length > opts[name]
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                    for s in v.slice(0, v.length - opts[name])
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                        to_delete.push(s)
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            cb()
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        (cb) ->
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            dbg("snapshots to make: #{misc.to_json(to_create)}")
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            if to_create.length > 0
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                f = (snap, cb) ->
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                    make_snapshot(opts.filesystem, snap, cb)
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                async.map(to_create, f, cb)
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            else
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                cb()
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        (cb) ->
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            dbg("snapshots to delete: #{to_delete}")
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            if to_delete.length > 0
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                f = (snap, cb) ->
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                    delete_snapshot(opts.filesystem, snap, cb)
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                async.map(to_delete, f, cb)
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            else
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                cb()
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    ], (err) -> opts.cb?(err))
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