Cloud Datastore is the best friend for App Engine developers, yeay!
However, it may be awkward to implement an incremental counter (like AUTO_INCREMENT in MySQL) over Datastore. The good alternative is to use Bigtable to implement a counter service.
Here is a prototype of such a counter service. getCount() returns an auto increment integer number starting from 1 with strong consistency. In this sample, five of go-routines keep getting counts until they receive 100 counts per routine which results in 500 counts in total.
Before running this on Cloud Shell, you need to create a Bigtable cluster and install golang client SDK with the following command.
$ go get -u all
main.go
package main import ( "flag" "encoding/binary" "log" "sync" "cloud.google.com/go/bigtable" "golang.org/x/net/context" ) // User-provided constants. const ( tableName = "CounterTable" columnFamilyName = "count" columnName = "" rowName = "mycounter" ) // sliceContains reports whether the provided string is present in the given slice of strings. func sliceContains(list []string, target string) bool { for _, s := range list { if s == target { return true } } return false } func main() { project := flag.String("project", "", "The Google Cloud Platform project ID. Required.") instance := flag.String("instance", "", "The Google Cloud Bigtable instance ID. Required.") flag.Parse() for _, f := range []string{"project", "instance"} { if flag.Lookup(f).Value.String() == "" { log.Fatalf("The %s flag is required.", f) } } ctx := context.Background() adminClient, err := bigtable.NewAdminClient(ctx, *project, *instance) if err != nil { log.Fatalf("Could not create admin client: %v", err) } tables, err := adminClient.Tables(ctx) if err != nil { log.Fatalf("Could not fetch table list: %v", err) } if !sliceContains(tables, tableName) { log.Printf("Creating table %s", tableName) if err := adminClient.CreateTable(ctx, tableName); err != nil { log.Fatalf("Could not create table %s: %v", tableName, err) } } tblInfo, err := adminClient.TableInfo(ctx, tableName) if err != nil { log.Fatalf("Could not read info for table %s: %v", tableName, err) } if !sliceContains(tblInfo.Families, columnFamilyName) { if err := adminClient.CreateColumnFamily(ctx, tableName, columnFamilyName); err != nil { log.Fatalf("Could not create column family %s: %v", columnFamilyName, err) } } client, err := bigtable.NewClient(ctx, *project, *instance) if err != nil { log.Fatalf("Could not create data operations client: %v", err) } tbl := client.Open(tableName) mut := bigtable.NewMutation() mut.Set(columnFamilyName, columnName, bigtable.Now(),[]byte{0, 0, 0, 0, 0, 0, 0, 0}) if err := tbl.Apply(ctx, rowName, mut); err != nil { log.Fatalf("Could not create row: %v", err) } // counter service function getCount := func() uint64 { rmw := bigtable.NewReadModifyWrite() rmw.Increment(columnFamilyName, columnName, 1) row, err := tbl.ApplyReadModifyWrite(ctx, rowName, rmw) if err != nil { log.Fatalf("Could not update row: %s %v", row, err) } data := binary.BigEndian.Uint64(row[columnFamilyName][0].Value) return data } var wg sync.WaitGroup for i := 0; i < 5; i++ { wg.Add(1) go func(id int) { log.Printf("Start client:%d", id) for j := 1; j < 101; j++ { data := getCount() log.Printf("\tclient:%d\t%s = %d\n", id, rowName, data) } log.Printf("Finished client:%d", id) wg.Done() }(i) } wg.Wait() log.Printf("Finished.") }
$ go run main.go -project bt-counter -instance mycounter 2016/11/11 10:55:54 Start client:4 2016/11/11 10:55:54 Start client:0 2016/11/11 10:55:54 Start client:1 2016/11/11 10:55:54 Start client:2 2016/11/11 10:55:54 Start client:3 2016/11/11 10:55:54 client:2 mycounter = 1 2016/11/11 10:55:54 client:1 mycounter = 2 2016/11/11 10:55:54 client:2 mycounter = 3 2016/11/11 10:55:54 client:0 mycounter = 4 2016/11/11 10:55:54 client:1 mycounter = 5 2016/11/11 10:55:54 client:2 mycounter = 6 2016/11/11 10:55:54 client:3 mycounter = 7 2016/11/11 10:55:54 client:0 mycounter = 8 2016/11/11 10:55:54 client:4 mycounter = 9 2016/11/11 10:55:54 client:2 mycounter = 10 2016/11/11 10:55:54 client:1 mycounter = 11 2016/11/11 10:55:54 client:3 mycounter = 12 2016/11/11 10:55:54 client:4 mycounter = 14 2016/11/11 10:55:54 client:2 mycounter = 15 2016/11/11 10:55:54 client:1 mycounter = 16 2016/11/11 10:55:54 client:4 mycounter = 17 2016/11/11 10:55:54 client:2 mycounter = 18 2016/11/11 10:55:54 client:1 mycounter = 19 2016/11/11 10:55:54 client:2 mycounter = 20 2016/11/11 10:55:54 client:1 mycounter = 21 2016/11/11 10:55:54 client:2 mycounter = 22 2016/11/11 10:55:54 client:0 mycounter = 13 2016/11/11 10:55:54 client:2 mycounter = 23 2016/11/11 10:55:54 client:1 mycounter = 24 2016/11/11 10:55:54 client:4 mycounter = 25 2016/11/11 10:55:54 client:3 mycounter = 26 2016/11/11 10:55:54 client:0 mycounter = 27 2016/11/11 10:55:54 client:2 mycounter = 28 2016/11/11 10:55:54 client:1 mycounter = 29 2016/11/11 10:55:54 client:4 mycounter = 30 2016/11/11 10:55:54 client:3 mycounter = 31 2016/11/11 10:55:54 client:0 mycounter = 32 2016/11/11 10:55:54 client:2 mycounter = 33 2016/11/11 10:55:54 client:1 mycounter = 34 2016/11/11 10:55:54 client:4 mycounter = 35 2016/11/11 10:55:54 client:3 mycounter = 36 2016/11/11 10:55:54 client:2 mycounter = 38 2016/11/11 10:55:54 client:0 mycounter = 37 2016/11/11 10:55:54 client:1 mycounter = 39 2016/11/11 10:55:54 client:4 mycounter = 40 2016/11/11 10:55:54 client:3 mycounter = 41 2016/11/11 10:55:54 client:2 mycounter = 42 2016/11/11 10:55:54 client:0 mycounter = 43 2016/11/11 10:55:54 client:1 mycounter = 44 2016/11/11 10:55:54 client:4 mycounter = 45 2016/11/11 10:55:54 client:3 mycounter = 46 2016/11/11 10:55:54 client:2 mycounter = 47 2016/11/11 10:55:54 client:1 mycounter = 49 2016/11/11 10:55:54 client:4 mycounter = 50 2016/11/11 10:55:54 client:0 mycounter = 48 2016/11/11 10:55:54 client:2 mycounter = 52 2016/11/11 10:55:54 client:1 mycounter = 53 2016/11/11 10:55:54 client:4 mycounter = 54 2016/11/11 10:55:54 client:0 mycounter = 55 2016/11/11 10:55:54 client:3 mycounter = 51 2016/11/11 10:55:54 client:2 mycounter = 56 2016/11/11 10:55:54 client:1 mycounter = 57 2016/11/11 10:55:54 client:4 mycounter = 58 2016/11/11 10:55:54 client:0 mycounter = 59 2016/11/11 10:55:54 client:3 mycounter = 60 2016/11/11 10:55:54 client:2 mycounter = 61 2016/11/11 10:55:54 client:1 mycounter = 62 2016/11/11 10:55:54 client:4 mycounter = 63 2016/11/11 10:55:54 client:0 mycounter = 64 2016/11/11 10:55:54 client:3 mycounter = 65 2016/11/11 10:55:54 client:2 mycounter = 66 2016/11/11 10:55:54 client:1 mycounter = 67 2016/11/11 10:55:54 client:4 mycounter = 68 2016/11/11 10:55:54 client:3 mycounter = 70 2016/11/11 10:55:55 client:4 mycounter = 73 2016/11/11 10:55:55 client:1 mycounter = 72 2016/11/11 10:55:55 client:2 mycounter = 71 2016/11/11 10:55:55 client:0 mycounter = 69 2016/11/11 10:55:55 client:3 mycounter = 74 2016/11/11 10:55:55 client:4 mycounter = 75 2016/11/11 10:55:55 client:1 mycounter = 76 2016/11/11 10:55:55 client:2 mycounter = 77 2016/11/11 10:55:55 client:0 mycounter = 78 2016/11/11 10:55:55 client:3 mycounter = 79 2016/11/11 10:55:55 client:4 mycounter = 80 2016/11/11 10:55:55 client:2 mycounter = 82 2016/11/11 10:55:55 client:1 mycounter = 81 2016/11/11 10:55:55 client:0 mycounter = 83 2016/11/11 10:55:55 client:3 mycounter = 84 2016/11/11 10:55:55 client:4 mycounter = 85 2016/11/11 10:55:55 client:2 mycounter = 86 2016/11/11 10:55:55 client:1 mycounter = 87 2016/11/11 10:55:55 client:0 mycounter = 88 2016/11/11 10:55:55 client:3 mycounter = 89 2016/11/11 10:55:55 client:4 mycounter = 90 2016/11/11 10:55:55 client:2 mycounter = 91 2016/11/11 10:55:55 client:1 mycounter = 92 2016/11/11 10:55:55 client:4 mycounter = 94 2016/11/11 10:55:55 client:0 mycounter = 93 2016/11/11 10:55:55 client:3 mycounter = 95 2016/11/11 10:55:55 client:2 mycounter = 96 2016/11/11 10:55:55 client:1 mycounter = 97 2016/11/11 10:55:55 client:0 mycounter = 98 2016/11/11 10:55:55 client:4 mycounter = 99 2016/11/11 10:55:55 client:3 mycounter = 100 2016/11/11 10:55:55 client:2 mycounter = 101 2016/11/11 10:55:55 client:1 mycounter = 102 2016/11/11 10:55:55 client:0 mycounter = 103 2016/11/11 10:55:55 client:4 mycounter = 104 2016/11/11 10:55:55 client:3 mycounter = 105 2016/11/11 10:55:55 client:2 mycounter = 106 2016/11/11 10:55:55 client:1 mycounter = 107 2016/11/11 10:55:55 client:0 mycounter = 108 2016/11/11 10:55:55 client:4 mycounter = 109 2016/11/11 10:55:55 client:3 mycounter = 110 2016/11/11 10:55:55 client:2 mycounter = 111 2016/11/11 10:55:55 client:1 mycounter = 112 2016/11/11 10:55:55 client:0 mycounter = 113 2016/11/11 10:55:55 client:4 mycounter = 114 2016/11/11 10:55:55 client:3 mycounter = 115 2016/11/11 10:55:55 client:2 mycounter = 116 2016/11/11 10:55:55 client:0 mycounter = 118 2016/11/11 10:55:55 client:4 mycounter = 119 2016/11/11 10:55:55 client:3 mycounter = 120 2016/11/11 10:55:55 client:2 mycounter = 121 2016/11/11 10:55:55 client:1 mycounter = 117 2016/11/11 10:55:55 client:0 mycounter = 122 2016/11/11 10:55:55 client:4 mycounter = 123 2016/11/11 10:55:55 client:3 mycounter = 124 2016/11/11 10:55:55 client:2 mycounter = 125 2016/11/11 10:55:55 client:1 mycounter = 126 2016/11/11 10:55:55 client:0 mycounter = 127 2016/11/11 10:55:55 client:4 mycounter = 128 2016/11/11 10:55:55 client:3 mycounter = 129 2016/11/11 10:55:55 client:2 mycounter = 130 2016/11/11 10:55:55 client:1 mycounter = 131 2016/11/11 10:55:55 client:0 mycounter = 132 2016/11/11 10:55:55 client:4 mycounter = 133 2016/11/11 10:55:55 client:3 mycounter = 134 2016/11/11 10:55:55 client:2 mycounter = 135 2016/11/11 10:55:55 client:1 mycounter = 136 2016/11/11 10:55:55 client:0 mycounter = 137 2016/11/11 10:55:55 client:4 mycounter = 138 2016/11/11 10:55:55 client:3 mycounter = 139 2016/11/11 10:55:55 client:1 mycounter = 140 2016/11/11 10:55:55 client:2 mycounter = 141 2016/11/11 10:55:55 client:0 mycounter = 142 2016/11/11 10:55:55 client:4 mycounter = 143 2016/11/11 10:55:55 client:3 mycounter = 144 2016/11/11 10:55:55 client:1 mycounter = 145 2016/11/11 10:55:55 client:2 mycounter = 146 2016/11/11 10:55:55 client:0 mycounter = 147 2016/11/11 10:55:55 client:4 mycounter = 148 2016/11/11 10:55:55 client:3 mycounter = 149 2016/11/11 10:55:55 client:1 mycounter = 150 2016/11/11 10:55:55 client:2 mycounter = 151 2016/11/11 10:55:55 client:4 mycounter = 152 2016/11/11 10:55:55 client:0 mycounter = 153 2016/11/11 10:55:55 client:3 mycounter = 154 2016/11/11 10:55:55 client:1 mycounter = 155 2016/11/11 10:55:55 client:2 mycounter = 156 2016/11/11 10:55:55 client:4 mycounter = 157 2016/11/11 10:55:55 client:0 mycounter = 158 2016/11/11 10:55:55 client:3 mycounter = 159 2016/11/11 10:55:55 client:1 mycounter = 160 2016/11/11 10:55:55 client:2 mycounter = 161 2016/11/11 10:55:55 client:4 mycounter = 162 2016/11/11 10:55:55 client:0 mycounter = 163 2016/11/11 10:55:55 client:3 mycounter = 164 2016/11/11 10:55:55 client:1 mycounter = 165 2016/11/11 10:55:55 client:2 mycounter = 166 2016/11/11 10:55:55 client:4 mycounter = 167 2016/11/11 10:55:55 client:0 mycounter = 168 2016/11/11 10:55:55 client:3 mycounter = 169 2016/11/11 10:55:55 client:2 mycounter = 171 2016/11/11 10:55:55 client:4 mycounter = 172 2016/11/11 10:55:55 client:0 mycounter = 173 2016/11/11 10:55:55 client:1 mycounter = 170 2016/11/11 10:55:55 client:3 mycounter = 174 2016/11/11 10:55:55 client:2 mycounter = 175 2016/11/11 10:55:55 client:4 mycounter = 176 2016/11/11 10:55:55 client:0 mycounter = 177 2016/11/11 10:55:55 client:1 mycounter = 178 2016/11/11 10:55:55 client:3 mycounter = 179 2016/11/11 10:55:55 client:2 mycounter = 180 2016/11/11 10:55:55 client:4 mycounter = 181 2016/11/11 10:55:55 client:0 mycounter = 182 2016/11/11 10:55:55 client:1 mycounter = 183 2016/11/11 10:55:55 client:3 mycounter = 184 2016/11/11 10:55:55 client:2 mycounter = 185 2016/11/11 10:55:55 client:4 mycounter = 186 2016/11/11 10:55:55 client:0 mycounter = 187 2016/11/11 10:55:55 client:1 mycounter = 188 2016/11/11 10:55:55 client:3 mycounter = 189 2016/11/11 10:55:55 client:2 mycounter = 190 2016/11/11 10:55:55 client:4 mycounter = 191 2016/11/11 10:55:55 client:0 mycounter = 192 2016/11/11 10:55:55 client:1 mycounter = 193 2016/11/11 10:55:55 client:3 mycounter = 194 2016/11/11 10:55:55 client:2 mycounter = 195 2016/11/11 10:55:55 client:4 mycounter = 196 2016/11/11 10:55:55 client:0 mycounter = 197 2016/11/11 10:55:55 client:1 mycounter = 198 2016/11/11 10:55:55 client:3 mycounter = 199 2016/11/11 10:55:55 client:2 mycounter = 200 2016/11/11 10:55:55 client:4 mycounter = 201 2016/11/11 10:55:55 client:0 mycounter = 202 2016/11/11 10:55:55 client:1 mycounter = 203 2016/11/11 10:55:55 client:3 mycounter = 204 2016/11/11 10:55:55 client:2 mycounter = 205 2016/11/11 10:55:55 client:4 mycounter = 206 2016/11/11 10:55:55 client:0 mycounter = 207 2016/11/11 10:55:55 client:1 mycounter = 208 2016/11/11 10:55:55 client:3 mycounter = 209 2016/11/11 10:55:55 client:2 mycounter = 210 2016/11/11 10:55:55 client:4 mycounter = 211 2016/11/11 10:55:55 client:0 mycounter = 212 2016/11/11 10:55:55 client:1 mycounter = 213 2016/11/11 10:55:55 client:3 mycounter = 214 2016/11/11 10:55:55 client:2 mycounter = 215 2016/11/11 10:55:55 client:4 mycounter = 216 2016/11/11 10:55:55 client:0 mycounter = 217 2016/11/11 10:55:55 client:1 mycounter = 218 2016/11/11 10:55:55 client:3 mycounter = 219 2016/11/11 10:55:55 client:2 mycounter = 220 2016/11/11 10:55:55 client:4 mycounter = 221 2016/11/11 10:55:55 client:0 mycounter = 222 2016/11/11 10:55:55 client:1 mycounter = 223 2016/11/11 10:55:55 client:3 mycounter = 224 2016/11/11 10:55:55 client:2 mycounter = 225 2016/11/11 10:55:55 client:0 mycounter = 227 2016/11/11 10:55:55 client:1 mycounter = 228 2016/11/11 10:55:55 client:4 mycounter = 226 2016/11/11 10:55:55 client:2 mycounter = 230 2016/11/11 10:55:55 client:3 mycounter = 229 2016/11/11 10:55:55 client:0 mycounter = 231 2016/11/11 10:55:55 client:1 mycounter = 232 2016/11/11 10:55:55 client:4 mycounter = 233 2016/11/11 10:55:55 client:2 mycounter = 234 2016/11/11 10:55:55 client:3 mycounter = 235 2016/11/11 10:55:55 client:0 mycounter = 236 2016/11/11 10:55:55 client:1 mycounter = 237 2016/11/11 10:55:55 client:4 mycounter = 238 2016/11/11 10:55:55 client:2 mycounter = 239 2016/11/11 10:55:55 client:3 mycounter = 240 2016/11/11 10:55:55 client:0 mycounter = 241 2016/11/11 10:55:55 client:1 mycounter = 242 2016/11/11 10:55:55 client:4 mycounter = 243 2016/11/11 10:55:55 client:2 mycounter = 244 2016/11/11 10:55:55 client:3 mycounter = 245 2016/11/11 10:55:55 client:0 mycounter = 246 2016/11/11 10:55:55 client:1 mycounter = 247 2016/11/11 10:55:55 client:4 mycounter = 248 2016/11/11 10:55:55 client:3 mycounter = 250 2016/11/11 10:55:55 client:2 mycounter = 249 2016/11/11 10:55:55 client:0 mycounter = 251 2016/11/11 10:55:55 client:1 mycounter = 252 2016/11/11 10:55:55 client:4 mycounter = 253 2016/11/11 10:55:55 client:3 mycounter = 254 2016/11/11 10:55:55 client:2 mycounter = 255 2016/11/11 10:55:55 client:0 mycounter = 256 2016/11/11 10:55:55 client:1 mycounter = 257 2016/11/11 10:55:55 client:4 mycounter = 258 2016/11/11 10:55:55 client:3 mycounter = 259 2016/11/11 10:55:55 client:2 mycounter = 260 2016/11/11 10:55:55 client:0 mycounter = 261 2016/11/11 10:55:55 client:1 mycounter = 262 2016/11/11 10:55:55 client:4 mycounter = 263 2016/11/11 10:55:55 client:3 mycounter = 264 2016/11/11 10:55:55 client:2 mycounter = 265 2016/11/11 10:55:55 client:0 mycounter = 266 2016/11/11 10:55:55 client:1 mycounter = 267 2016/11/11 10:55:55 client:4 mycounter = 268 2016/11/11 10:55:55 client:3 mycounter = 269 2016/11/11 10:55:55 client:2 mycounter = 270 2016/11/11 10:55:55 client:0 mycounter = 271 2016/11/11 10:55:55 client:1 mycounter = 272 2016/11/11 10:55:55 client:4 mycounter = 273 2016/11/11 10:55:55 client:3 mycounter = 274 2016/11/11 10:55:55 client:2 mycounter = 275 2016/11/11 10:55:55 client:0 mycounter = 276 2016/11/11 10:55:55 client:1 mycounter = 277 2016/11/11 10:55:55 client:4 mycounter = 278 2016/11/11 10:55:55 client:3 mycounter = 279 2016/11/11 10:55:55 client:2 mycounter = 280 2016/11/11 10:55:55 client:0 mycounter = 281 2016/11/11 10:55:55 client:1 mycounter = 282 2016/11/11 10:55:55 client:4 mycounter = 283 2016/11/11 10:55:55 client:3 mycounter = 284 2016/11/11 10:55:55 client:2 mycounter = 285 2016/11/11 10:55:55 client:0 mycounter = 286 2016/11/11 10:55:55 client:1 mycounter = 287 2016/11/11 10:55:55 client:4 mycounter = 288 2016/11/11 10:55:55 client:0 mycounter = 290 2016/11/11 10:55:55 client:3 mycounter = 289 2016/11/11 10:55:55 client:2 mycounter = 291 2016/11/11 10:55:55 client:1 mycounter = 292 2016/11/11 10:55:55 client:4 mycounter = 293 2016/11/11 10:55:55 client:0 mycounter = 294 2016/11/11 10:55:55 client:3 mycounter = 295 2016/11/11 10:55:55 client:2 mycounter = 296 2016/11/11 10:55:55 client:1 mycounter = 297 2016/11/11 10:55:55 client:4 mycounter = 298 2016/11/11 10:55:55 client:0 mycounter = 299 2016/11/11 10:55:55 client:3 mycounter = 300 2016/11/11 10:55:55 client:2 mycounter = 301 2016/11/11 10:55:55 client:1 mycounter = 302 2016/11/11 10:55:55 client:4 mycounter = 303 2016/11/11 10:55:55 client:0 mycounter = 304 2016/11/11 10:55:55 client:3 mycounter = 305 2016/11/11 10:55:55 client:2 mycounter = 306 2016/11/11 10:55:55 client:1 mycounter = 307 2016/11/11 10:55:55 client:4 mycounter = 308 2016/11/11 10:55:55 client:0 mycounter = 309 2016/11/11 10:55:55 client:3 mycounter = 310 2016/11/11 10:55:55 client:2 mycounter = 311 2016/11/11 10:55:55 client:1 mycounter = 312 2016/11/11 10:55:55 client:4 mycounter = 313 2016/11/11 10:55:55 client:3 mycounter = 315 2016/11/11 10:55:55 client:0 mycounter = 314 2016/11/11 10:55:55 client:2 mycounter = 316 2016/11/11 10:55:55 client:1 mycounter = 317 2016/11/11 10:55:55 client:3 mycounter = 318 2016/11/11 10:55:55 client:4 mycounter = 319 2016/11/11 10:55:55 client:0 mycounter = 320 2016/11/11 10:55:55 client:1 mycounter = 322 2016/11/11 10:55:55 client:2 mycounter = 321 2016/11/11 10:55:55 client:3 mycounter = 323 2016/11/11 10:55:55 client:4 mycounter = 324 2016/11/11 10:55:55 client:0 mycounter = 325 2016/11/11 10:55:55 client:1 mycounter = 326 2016/11/11 10:55:55 client:2 mycounter = 327 2016/11/11 10:55:55 client:3 mycounter = 328 2016/11/11 10:55:55 client:1 mycounter = 330 2016/11/11 10:55:55 client:4 mycounter = 329 2016/11/11 10:55:55 client:0 mycounter = 331 2016/11/11 10:55:55 client:2 mycounter = 332 2016/11/11 10:55:55 client:3 mycounter = 333 2016/11/11 10:55:55 client:1 mycounter = 334 2016/11/11 10:55:55 client:4 mycounter = 335 2016/11/11 10:55:55 client:0 mycounter = 336 2016/11/11 10:55:55 client:2 mycounter = 337 2016/11/11 10:55:55 client:3 mycounter = 338 2016/11/11 10:55:55 client:1 mycounter = 339 2016/11/11 10:55:55 client:4 mycounter = 340 2016/11/11 10:55:55 client:0 mycounter = 341 2016/11/11 10:55:55 client:2 mycounter = 342 2016/11/11 10:55:55 client:3 mycounter = 343 2016/11/11 10:55:55 client:4 mycounter = 345 2016/11/11 10:55:55 client:0 mycounter = 346 2016/11/11 10:55:55 client:2 mycounter = 347 2016/11/11 10:55:55 client:1 mycounter = 344 2016/11/11 10:55:55 client:3 mycounter = 348 2016/11/11 10:55:55 client:4 mycounter = 349 2016/11/11 10:55:55 client:0 mycounter = 350 2016/11/11 10:55:55 client:2 mycounter = 351 2016/11/11 10:55:55 client:1 mycounter = 352 2016/11/11 10:55:55 client:4 mycounter = 354 2016/11/11 10:55:55 client:3 mycounter = 353 2016/11/11 10:55:55 client:0 mycounter = 355 2016/11/11 10:55:55 client:2 mycounter = 356 2016/11/11 10:55:55 client:1 mycounter = 357 2016/11/11 10:55:55 client:4 mycounter = 358 2016/11/11 10:55:55 client:3 mycounter = 359 2016/11/11 10:55:55 client:0 mycounter = 360 2016/11/11 10:55:55 client:2 mycounter = 361 2016/11/11 10:55:55 client:1 mycounter = 362 2016/11/11 10:55:55 client:4 mycounter = 363 2016/11/11 10:55:55 client:3 mycounter = 364 2016/11/11 10:55:55 client:2 mycounter = 366 2016/11/11 10:55:55 client:1 mycounter = 367 2016/11/11 10:55:55 client:0 mycounter = 365 2016/11/11 10:55:55 client:4 mycounter = 368 2016/11/11 10:55:55 client:3 mycounter = 369 2016/11/11 10:55:55 client:1 mycounter = 371 2016/11/11 10:55:55 client:2 mycounter = 370 2016/11/11 10:55:55 client:0 mycounter = 372 2016/11/11 10:55:55 client:4 mycounter = 373 2016/11/11 10:55:55 client:3 mycounter = 374 2016/11/11 10:55:55 client:1 mycounter = 375 2016/11/11 10:55:55 client:2 mycounter = 376 2016/11/11 10:55:55 client:0 mycounter = 377 2016/11/11 10:55:55 client:4 mycounter = 378 2016/11/11 10:55:55 client:3 mycounter = 379 2016/11/11 10:55:55 client:1 mycounter = 380 2016/11/11 10:55:55 client:2 mycounter = 381 2016/11/11 10:55:55 client:0 mycounter = 382 2016/11/11 10:55:55 client:4 mycounter = 383 2016/11/11 10:55:55 client:3 mycounter = 384 2016/11/11 10:55:55 client:2 mycounter = 386 2016/11/11 10:55:55 client:1 mycounter = 385 2016/11/11 10:55:55 client:0 mycounter = 387 2016/11/11 10:55:55 client:4 mycounter = 388 2016/11/11 10:55:55 client:3 mycounter = 389 2016/11/11 10:55:55 client:2 mycounter = 390 2016/11/11 10:55:55 client:1 mycounter = 391 2016/11/11 10:55:55 client:0 mycounter = 392 2016/11/11 10:55:55 client:4 mycounter = 393 2016/11/11 10:55:55 client:3 mycounter = 394 2016/11/11 10:55:55 client:2 mycounter = 395 2016/11/11 10:55:55 client:1 mycounter = 396 2016/11/11 10:55:55 client:4 mycounter = 398 2016/11/11 10:55:55 client:0 mycounter = 397 2016/11/11 10:55:55 client:3 mycounter = 399 2016/11/11 10:55:55 client:2 mycounter = 400 2016/11/11 10:55:55 client:4 mycounter = 402 2016/11/11 10:55:55 client:1 mycounter = 401 2016/11/11 10:55:55 client:0 mycounter = 403 2016/11/11 10:55:55 client:3 mycounter = 404 2016/11/11 10:55:55 client:4 mycounter = 405 2016/11/11 10:55:55 client:2 mycounter = 406 2016/11/11 10:55:55 client:1 mycounter = 407 2016/11/11 10:55:55 client:0 mycounter = 408 2016/11/11 10:55:55 client:3 mycounter = 409 2016/11/11 10:55:55 client:4 mycounter = 410 2016/11/11 10:55:55 client:2 mycounter = 411 2016/11/11 10:55:55 client:1 mycounter = 412 2016/11/11 10:55:55 client:3 mycounter = 414 2016/11/11 10:55:55 client:0 mycounter = 413 2016/11/11 10:55:55 client:4 mycounter = 415 2016/11/11 10:55:55 client:2 mycounter = 416 2016/11/11 10:55:55 client:3 mycounter = 418 2016/11/11 10:55:55 client:1 mycounter = 417 2016/11/11 10:55:55 client:0 mycounter = 419 2016/11/11 10:55:55 client:4 mycounter = 420 2016/11/11 10:55:55 client:2 mycounter = 421 2016/11/11 10:55:55 client:3 mycounter = 422 2016/11/11 10:55:55 client:1 mycounter = 423 2016/11/11 10:55:55 client:0 mycounter = 424 2016/11/11 10:55:55 client:2 mycounter = 426 2016/11/11 10:55:55 client:4 mycounter = 425 2016/11/11 10:55:55 client:3 mycounter = 427 2016/11/11 10:55:55 client:1 mycounter = 428 2016/11/11 10:55:55 client:0 mycounter = 429 2016/11/11 10:55:55 client:2 mycounter = 430 2016/11/11 10:55:55 client:4 mycounter = 431 2016/11/11 10:55:55 client:3 mycounter = 432 2016/11/11 10:55:55 client:0 mycounter = 433 2016/11/11 10:55:55 client:2 mycounter = 435 2016/11/11 10:55:55 client:1 mycounter = 434 2016/11/11 10:55:55 client:4 mycounter = 436 2016/11/11 10:55:55 client:3 mycounter = 437 2016/11/11 10:55:55 client:0 mycounter = 438 2016/11/11 10:55:55 client:2 mycounter = 439 2016/11/11 10:55:55 client:1 mycounter = 440 2016/11/11 10:55:55 client:3 mycounter = 442 2016/11/11 10:55:55 client:0 mycounter = 443 2016/11/11 10:55:55 client:4 mycounter = 441 2016/11/11 10:55:55 client:2 mycounter = 444 2016/11/11 10:55:55 client:0 mycounter = 446 2016/11/11 10:55:55 client:1 mycounter = 445 2016/11/11 10:55:55 client:3 mycounter = 447 2016/11/11 10:55:55 client:4 mycounter = 448 2016/11/11 10:55:55 client:2 mycounter = 449 2016/11/11 10:55:55 client:1 mycounter = 450 2016/11/11 10:55:55 client:0 mycounter = 451 2016/11/11 10:55:55 client:3 mycounter = 452 2016/11/11 10:55:55 client:1 mycounter = 454 2016/11/11 10:55:55 client:4 mycounter = 453 2016/11/11 10:55:55 client:2 mycounter = 455 2016/11/11 10:55:55 client:0 mycounter = 456 2016/11/11 10:55:55 client:1 mycounter = 458 2016/11/11 10:55:55 client:3 mycounter = 457 2016/11/11 10:55:55 client:4 mycounter = 459 2016/11/11 10:55:55 client:2 mycounter = 460 2016/11/11 10:55:55 client:0 mycounter = 461 2016/11/11 10:55:55 client:3 mycounter = 463 2016/11/11 10:55:55 client:1 mycounter = 462 2016/11/11 10:55:55 client:4 mycounter = 464 2016/11/11 10:55:55 client:2 mycounter = 465 2016/11/11 10:55:55 client:0 mycounter = 466 2016/11/11 10:55:55 client:3 mycounter = 467 2016/11/11 10:55:55 client:1 mycounter = 468 2016/11/11 10:55:55 client:2 mycounter = 469 2016/11/11 10:55:55 client:4 mycounter = 470 2016/11/11 10:55:55 client:0 mycounter = 471 2016/11/11 10:55:55 client:3 mycounter = 472 2016/11/11 10:55:55 client:2 mycounter = 473 2016/11/11 10:55:55 Finished client:2 2016/11/11 10:55:55 client:1 mycounter = 474 2016/11/11 10:55:55 client:4 mycounter = 475 2016/11/11 10:55:55 client:0 mycounter = 476 2016/11/11 10:55:55 client:3 mycounter = 477 2016/11/11 10:55:55 client:4 mycounter = 478 2016/11/11 10:55:55 client:1 mycounter = 479 2016/11/11 10:55:55 client:0 mycounter = 480 2016/11/11 10:55:55 client:4 mycounter = 481 2016/11/11 10:55:55 client:3 mycounter = 482 2016/11/11 10:55:55 client:1 mycounter = 483 2016/11/11 10:55:55 client:0 mycounter = 484 2016/11/11 10:55:55 client:4 mycounter = 485 2016/11/11 10:55:55 client:3 mycounter = 486 2016/11/11 10:55:55 client:1 mycounter = 487 2016/11/11 10:55:55 client:0 mycounter = 488 2016/11/11 10:55:55 client:1 mycounter = 491 2016/11/11 10:55:55 Finished client:1 2016/11/11 10:55:55 client:3 mycounter = 490 2016/11/11 10:55:55 client:4 mycounter = 489 2016/11/11 10:55:55 client:0 mycounter = 492 2016/11/11 10:55:55 client:3 mycounter = 493 2016/11/11 10:55:55 client:4 mycounter = 494 2016/11/11 10:55:55 Finished client:4 2016/11/11 10:55:55 client:0 mycounter = 495 2016/11/11 10:55:55 client:3 mycounter = 496 2016/11/11 10:55:55 client:0 mycounter = 497 2016/11/11 10:55:55 client:3 mycounter = 498 2016/11/11 10:55:55 client:0 mycounter = 499 2016/11/11 10:55:55 Finished client:0 2016/11/11 10:55:55 client:3 mycounter = 500 2016/11/11 10:55:55 Finished client:3 2016/11/11 10:55:55 Finished.
It works! Now you can create an API service for providing counters running on App Engine. You may need to use a flexible environment since go client library is not supported on the standard environment at the time of writing.
Disclaimer: All code snippets are released under Apache 2.0 License. This is not an official Google product.
