ducky/devices

Paddy 2015-11-12 Parent:600326d50e74 Child:408abf6e48d3

4:7bc6a84ac906 Go to Latest

ducky/devices/devices.go

Minimal Memstore implementation. Create an in-memory version of the Storer that meets the minimal requirements set by our Storer tests so far.

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paddy@0 1 package devices
paddy@0 2
paddy@0 3 import (
paddy@0 4 "errors"
paddy@0 5 "log"
paddy@0 6 "time"
paddy@0 7
paddy@0 8 "golang.org/x/net/context"
paddy@0 9
paddy@0 10 "code.secondbit.org/uuid.hg"
paddy@0 11 )
paddy@0 12
paddy@0 13 var (
paddy@0 14 // ErrDeviceNotFound is returned when the specified device couldn't be found.
paddy@0 15 ErrDeviceNotFound = errors.New("device not found")
paddy@0 16 )
paddy@0 17
paddy@0 18 // Device represents a specific device that updates can be pushed to.
paddy@0 19 type Device struct {
paddy@0 20 ID uuid.ID
paddy@0 21 Name string
paddy@0 22 Owner uuid.ID
paddy@0 23 Type DeviceType
paddy@0 24 Created time.Time
paddy@0 25 LastSeen time.Time
paddy@0 26 PushToken string
paddy@0 27 }
paddy@0 28
paddy@0 29 // ApplyChange returns a Device that is a copy of the passed Device,
paddy@0 30 // but with the passed DeviceChange applied.
paddy@0 31 func ApplyChange(d Device, change DeviceChange) Device {
paddy@0 32 result := d
paddy@0 33 if change.Name != nil {
paddy@0 34 result.Name = *change.Name
paddy@0 35 }
paddy@0 36 if change.Owner != nil {
paddy@0 37 result.Owner = *change.Owner
paddy@0 38 } else {
paddy@0 39 // We don't want to accidentally leave a slice that
paddy@0 40 // is owned by both behind.
paddy@0 41 result.Owner = d.Owner.Copy()
paddy@0 42 }
paddy@0 43 if change.Type != nil {
paddy@0 44 result.Type = *change.Type
paddy@0 45 }
paddy@0 46 if change.Created != nil {
paddy@0 47 result.Created = *change.Created
paddy@0 48 }
paddy@0 49 if change.LastSeen != nil {
paddy@0 50 result.LastSeen = *change.LastSeen
paddy@0 51 }
paddy@0 52 if change.PushToken != nil {
paddy@0 53 result.PushToken = *change.PushToken
paddy@0 54 }
paddy@0 55 return result
paddy@0 56 }
paddy@0 57
paddy@0 58 // DeviceChange represents a set of changes to a Device that will be used
paddy@0 59 // to update a Device.
paddy@0 60 type DeviceChange struct {
paddy@0 61 DeviceID uuid.ID
paddy@0 62 Name *string
paddy@0 63 Owner *uuid.ID
paddy@0 64 Type *DeviceType
paddy@0 65 Created *time.Time
paddy@0 66 LastSeen *time.Time
paddy@0 67 PushToken *string
paddy@0 68 }
paddy@0 69
paddy@0 70 // Storer is an interface to control how data is stored in and retrieved from
paddy@0 71 // the datastore.
paddy@0 72 type Storer interface {
paddy@0 73 GetDevices(ids []uuid.ID, c context.Context) (map[string]Device, error)
paddy@0 74 UpdateDevice(change DeviceChange, c context.Context) error
paddy@0 75 DeleteDevices(ids []uuid.ID, c context.Context) error
paddy@0 76 CreateDevices(devices []Device, c context.Context) error
paddy@0 77 ListDevicesByOwner(user uuid.ID, c context.Context) ([]Device, error)
paddy@0 78
paddy@0 79 // These are used for testing only.
paddy@0 80 Factory(c context.Context) (Storer, error)
paddy@0 81 Destroy(c context.Context) error
paddy@0 82 }
paddy@0 83
paddy@0 84 // GetMany returns as many of the Devices specified by the passed IDs as possible.
paddy@0 85 // They are returned as a map, with the key being the string version of the ID.
paddy@0 86 // No error will be returned if a Device can't be found.
paddy@0 87 func GetMany(ids []uuid.ID, c context.Context) (map[string]Device, error) {
paddy@0 88 results := map[string]Device{}
paddy@0 89 storer, err := getStorer(c)
paddy@0 90 if err != nil {
paddy@0 91 log.Printf("Error retrieving Storer: %+v\n", err)
paddy@0 92 return results, err
paddy@0 93 }
paddy@0 94 results, err = storer.GetDevices(ids, c)
paddy@0 95 if err != nil {
paddy@0 96 log.Printf("Error retrieving Devices from %T: %+v\n", storer, err)
paddy@0 97 return results, err
paddy@0 98 }
paddy@0 99 return results, nil
paddy@0 100 }
paddy@0 101
paddy@0 102 // Get returns the Device specified by the passed ID. If the Device can't be found,
paddy@0 103 // an ErrDeviceNotFound error is returned.
paddy@0 104 func Get(id uuid.ID, c context.Context) (Device, error) {
paddy@0 105 results, err := GetMany([]uuid.ID{id}, c)
paddy@0 106 if err != nil {
paddy@0 107 return Device{}, err
paddy@0 108 }
paddy@0 109 result, ok := results[id.String()]
paddy@0 110 if !ok {
paddy@0 111 return Device{}, ErrDeviceNotFound
paddy@0 112 }
paddy@0 113 return result, nil
paddy@0 114 }
paddy@0 115
paddy@0 116 // Update applies the DeviceChange to the passed Device, and returns the result. If
paddy@0 117 // the Device can't be found, an ErrDeviceNotFound error was returned.
paddy@0 118 func Update(device Device, change DeviceChange, c context.Context) (Device, error) {
paddy@0 119 storer, err := getStorer(c)
paddy@0 120 if err != nil {
paddy@0 121 log.Printf("Error retrieving Storer: %+v\n", err)
paddy@0 122 return Device{}, err
paddy@0 123 }
paddy@0 124 change.DeviceID = device.ID
paddy@0 125 err = storer.UpdateDevice(change, c)
paddy@0 126 if err != nil {
paddy@0 127 return Device{}, err
paddy@0 128 }
paddy@0 129 return ApplyChange(device, change), nil
paddy@0 130 }
paddy@0 131
paddy@0 132 // DeleteMany removes the passed IDs from the datastore. No error is returned if the
paddy@0 133 // ID doesn't correspond to a Device in the datastore.
paddy@0 134 func DeleteMany(ids []uuid.ID, c context.Context) error {
paddy@0 135 storer, err := getStorer(c)
paddy@0 136 if err != nil {
paddy@0 137 log.Printf("Error retrieving Storer: %+v\n", err)
paddy@0 138 return err
paddy@0 139 }
paddy@0 140 return storer.DeleteDevices(ids, c)
paddy@0 141 }
paddy@0 142
paddy@0 143 // Delete removes the passed ID from the datastore. No error is returned if the ID doesn't
paddy@0 144 // correspond to a Device in the datastore.
paddy@0 145 func Delete(id uuid.ID, c context.Context) error {
paddy@0 146 return DeleteMany([]uuid.ID{id}, c)
paddy@0 147 }
paddy@0 148
paddy@0 149 // CreateMany stores the passed Devices in the datastore, assigning default values if
paddy@0 150 // necessary. The Devices that were ultimately stored (including any default values, if
paddy@0 151 // applicable) are returned.
paddy@0 152 func CreateMany(devices []Device, c context.Context) ([]Device, error) {
paddy@0 153 storer, err := getStorer(c)
paddy@0 154 if err != nil {
paddy@0 155 log.Printf("Error retrieving Storer: %+v\n", err)
paddy@0 156 return []Device{}, err
paddy@0 157 }
paddy@0 158 modified := make([]Device, 0, len(devices))
paddy@0 159 for _, device := range devices {
paddy@0 160 if device.ID.IsZero() {
paddy@0 161 device.ID = uuid.NewID()
paddy@0 162 }
paddy@0 163 if device.Created.IsZero() {
paddy@0 164 device.Created = time.Now()
paddy@0 165 }
paddy@0 166 if device.LastSeen.IsZero() {
paddy@0 167 device.LastSeen = time.Now()
paddy@0 168 }
paddy@0 169 modified = append(modified, device)
paddy@0 170 }
paddy@0 171 err = storer.CreateDevices(devices, c)
paddy@0 172 if err != nil {
paddy@0 173 return []Device{}, err
paddy@0 174 }
paddy@0 175 return modified, nil
paddy@0 176 }
paddy@0 177
paddy@0 178 // Create stores the passed Device in the datastore, assigning default values if
paddy@0 179 // necessary. The Devices that were ultimately stored (including any default values, if
paddy@0 180 // applicable) are returned.
paddy@0 181 func Create(device Device, c context.Context) (Device, error) {
paddy@0 182 devices, err := CreateMany([]Device{device}, c)
paddy@0 183 if err != nil {
paddy@0 184 return Device{}, err
paddy@0 185 }
paddy@0 186 // There should never be a case where we don't return a result.
paddy@0 187 // Ideally, we'd return an error here instead of letting the panic
paddy@0 188 // happen, but seeing as I can't come up with a reason the error would
paddy@0 189 // occur, I'm having trouble coming up with a reasonable error to return.
paddy@0 190 return devices[0], nil
paddy@0 191 }
paddy@0 192
paddy@0 193 // ListByOwner returns a slice of all the Devices with an Owner property that
paddy@0 194 // matches the passed ID. There's no guarantee on the order the Devices will be
paddy@0 195 // returned in.
paddy@0 196 func ListByOwner(user uuid.ID, c context.Context) ([]Device, error) {
paddy@0 197 // BUG(paddy): Eventually, we'll need to support paging for devices. But right now, I don't foresee any user creating enough of them to make pagination worthwhile.
paddy@0 198 storer, err := getStorer(c)
paddy@0 199 if err != nil {
paddy@0 200 log.Printf("Error retrieving Storer: %+v\n", err)
paddy@0 201 return []Device{}, err
paddy@0 202 }
paddy@0 203 devices, err := storer.ListDevicesByOwner(user, c)
paddy@0 204 return devices, err
paddy@0 205 }