Add OnDemand mode

Author: bartelink

README.md

@@ -37,8 +37,8 @@ open Amazon.DynamoDBv2
 open FSharp.AWS.DynamoDB.Scripting // Expose non-Async methods, e.g. PutItem/GetItem
 
 let client : IAmazonDynamoDB = ``your DynamoDB client instance``
-let throughput = ProvisionedThroughput (readCapacityUnits = 1L, writeCapacityUnits = 10L)
-let table = TableContext.Initialize<WorkItemInfo>(client, tableName = "workItems", throughput)
+let throughput = ProvisionedThroughput(readCapacityUnits = 1L, writeCapacityUnits = 10L)
+let table = TableContext.Initialize<WorkItemInfo>(client, tableName = "workItems", Provisioned throughput)
 
 let workItem = { ProcessId = 0L ; WorkItemId = 1L ; Name = "Test" ; UUID = guid() ; Dependencies = set ["mscorlib"] ; Started = None }
 
@@ -120,8 +120,8 @@ type Counter private (table : TableContext<CounterEntry>, key : TableKey) =
 
     static member Create(client : IAmazonDynamoDB, tableName : string) = async {
         let table = TableContext<CounterEntry>(client, tableName)
-        let throughput = ProvisionedThroughput(readCapacityUnits = 100L, writeCapacityUnits = 100L)        
-        do! table.InitializeTableAsync throughput
+        let throughput = ProvisionedThroughput(readCapacityUnits = 10L, writeCapacityUnits = 10L)        
+        do! table.InitializeTableAsync(Provisioned throughput)
         let initialEntry = { Id = Guid.NewGuid() ; Value = 0L }
         let! key = table.PutItemAsync(initialEntry)
         return Counter(table, key)

RELEASE_NOTES.md

@@ -10,6 +10,7 @@
   * Added `TableContext.VerifyTableAsync` overload that only performs verification but never creates a Table
   * Added `TableContext.InitializeTableAsync` (replaces `TableContext.VerifyTableAsync(createIfNotExists = true)`)
   * Added `TableContext.ProvisionTableAsync` (as per `InitializeTableAsync` but does an `UpdateProvisionedThroughputAsync` if throughput has changed)
+  * Added Support for `Throughput.OnDemand` mode (sets `BillingMode` to `PAY_PER_REQUEST` rather than attempting to configure a `ProvisionedThroughput`)
   * Removed `TableContext.CreateAsync` (replace with `TableContext.VerifyTableAsync` or `InitializeTableAsync`)
 
 ### 0.9.3-beta

src/FSharp.AWS.DynamoDB/RecordKeySchema.fs

@@ -369,12 +369,10 @@ type TableKeySchemata with
                 yield! td.LocalSecondaryIndexes |> Seq.map mkLocalSecondaryIndex |])
 
     /// Create a CreateTableRequest using supplied key schema
-    member schema.CreateCreateTableRequest (tableName : string, provisionedThroughput : ProvisionedThroughput) =
+    member schema.CreateCreateTableRequest(tableName : string) =
         let ctr = CreateTableRequest(TableName = tableName)
         let inline mkKSE n t = KeySchemaElement(n, t)
 
-        ctr.ProvisionedThroughput <- provisionedThroughput
-
         let keyAttrs = new Dictionary<string, KeyAttributeSchema>()
         for tks in schema.Schemata do
             keyAttrs.[tks.HashKey.AttributeName] <- tks.HashKey
@@ -391,7 +389,6 @@ type TableKeySchemata with
                 gsi.KeySchema.Add <| mkKSE tks.HashKey.AttributeName KeyType.HASH
                 tks.RangeKey |> Option.iter (fun rk -> gsi.KeySchema.Add <| mkKSE rk.AttributeName KeyType.RANGE)
                 gsi.Projection <- Projection(ProjectionType = ProjectionType.ALL)
-                gsi.ProvisionedThroughput <- provisionedThroughput
                 ctr.GlobalSecondaryIndexes.Add gsi
 
             | LocalSecondaryIndex name ->

src/FSharp.AWS.DynamoDB/Script.fsx

@@ -54,8 +54,8 @@ type Test =
         Bytes : byte[]
     }
 
-let autoCreate = InitializationMode.CreateIfNotExists (ProvisionedThroughput (100L, 100L))
-let table = TableContext.Initialize<Test>(ddb, "test", mode = autoCreate)
+let throughput = ProvisionedThroughput(readCapacityUnits = 10L, writeCapacityUnits = 10L)
+let table = TableContext.Initialize<Test>(ddb, "test", Provisioned throughput)
 
 let value = { HashKey = Guid.NewGuid() ; List = [] ; RangeKey = "2" ; Value = 3.1415926 ; Date = DateTimeOffset.Now + TimeSpan.FromDays 2. ; Value2 = None ; Values = [|{ A = "foo" ; B = System.Reflection.BindingFlags.Instance }|] ; Map = Map.ofList [("A1",1)] ; Set = [set [1L];set [2L]] ; Bytes = [|1uy..10uy|]; String = ref "1a" ; Unions = [A 42; B("42",3)]}
 
@@ -126,8 +126,9 @@ type EasyCounters private (table : TableContext<CounterEntry>) =
     static member Create(client : IAmazonDynamoDB, tableName : string) : Async<EasyCounters> = async {
         let table = TableContext<CounterEntry>(client, tableName)
         // Create the table if necessary. Verifies schema is correct if it has already been created
-        let throughput = ProvisionedThroughput(readCapacityUnits = 100L, writeCapacityUnits = 100L)
-        do! table.InitializeTableAsync throughput
+        // NOTE the hard coded initial throughput provisioning - arguably this belongs outside of your application logic
+        let throughput = ProvisionedThroughput(readCapacityUnits = 10L, writeCapacityUnits = 10L)
+        do! table.InitializeTableAsync(Provisioned throughput)
         return EasyCounters(table)
     }
 
@@ -141,7 +142,8 @@ type SimpleCounters private (table : TableContext<CounterEntry>) =
         let table = TableContext<CounterEntry>(client, tableName)
         // normally, RCU/WCU provisioning only happens first time the Table is created and is then considered an external concern
         // here we use `ProvisionTableAsync` instead of `InitializeAsync` to reset it each time we start the app
-        table.ProvisionTableAsync(ProvisionedThroughput (readCapacityUnits, writeCapacityUnits))
+        let provisionedThroughput = ProvisionedThroughput(readCapacityUnits, writeCapacityUnits)
+        table.ProvisionTableAsync(Provisioned provisionedThroughput)
 
     /// We only want to do the initialization bit once per instance of our application
     /// Similar to EasyCounters.Create in that it ensures the table is provisioned correctly
@@ -168,11 +170,11 @@ let e2 = e.StartCounter() |> Async.RunSynchronously
 e1.Incr() |> Async.RunSynchronously
 e2.Incr() |> Async.RunSynchronously
 
-SimpleCounters.Provision(ddb, "testing-pre-provisioned", 100L, 100L) |> Async.RunSynchronously
+SimpleCounters.Provision(ddb, "testing-pre-provisioned", readCapacityUnits = 10L, writeCapacityUnits = 10L) |> Async.RunSynchronously
 // The consuming code can assume the provisioning has been carried out as part of the deploy
 // that allows the creation to be synchronous (and not impede application startup)
 let s = SimpleCounters.Create(ddb, "testing-pre-provisioned")
-let s1 = s.StartCounter() |> Async.RunSynchronously // Would throw if Provision has not been carried out
+let s1 = s.StartCounter() |> Async.RunSynchronously // Throws if Provision step has not been executed
 s1.Incr() |> Async.RunSynchronously
 
 // Alternately, we can have the app do an extra call (and have some asynchronous initialization work) to check the table is ready

src/FSharp.AWS.DynamoDB/TableContext.fs

@@ -19,6 +19,19 @@ type ResourceNotFoundException = Amazon.DynamoDBv2.Model.ResourceNotFoundExcepti
 /// Represents the provisioned throughput for given table or index
 type ProvisionedThroughput = Amazon.DynamoDBv2.Model.ProvisionedThroughput
 
+/// Represents the throughput configuration for a Table
+type Throughput =
+    | Provisioned of ProvisionedThroughput
+    | OnDemand
+module internal Throughput =
+    let applyToCreateRequest (req : CreateTableRequest) = function
+        | Provisioned t ->
+            req.ProvisionedThroughput <- t
+            for gsi in req.GlobalSecondaryIndexes do
+                gsi.ProvisionedThroughput <- t
+        | OnDemand ->
+            req.BillingMode <- BillingMode.PAY_PER_REQUEST
+
 /// Represents the operation performed on the table, for metrics collection purposes
 type Operation = GetItem | PutItem | UpdateItem | DeleteItem | BatchGetItems | BatchWriteItems | Scan | Query
 
@@ -973,10 +986,13 @@ type TableContext<'TRecord> internal
 
         checkOrCreate 9 // up to 9 retries, i.e. 10 attempts before we let exception propagate
 
-    member internal _.InternalCreateTableRequest(throughput) =
-        template.Info.Schemata.CreateCreateTableRequest(tableName, throughput)
-    member internal t.InternalCreateOrValidateTableAsync(createThroughput) =
-        t.InternalProvision(fun () -> t.InternalCreateTableRequest(createThroughput))
+    member internal _.InternalCreateTableRequest(applyThroughput) =
+        let req = template.Info.Schemata.CreateCreateTableRequest(tableName)
+        applyThroughput req
+        req
+
+    member internal t.InternalCreateOrValidateTableAsync(throughput) =
+        t.InternalProvision(fun () -> t.InternalCreateTableRequest(fun r -> Throughput.applyToCreateRequest r throughput))
 
     /// <summary>
     /// Asynchronously verify that the table exists and is compatible with record key schema, or throw.<br/>
@@ -990,21 +1006,24 @@ type TableContext<'TRecord> internal
     /// If the table is not present, it is provisioned, with the specified <c>throughput</c>.<br/>
     /// See also <c>VerifyTableAsync</c>, which only verifies the Table is present and correct.
     /// </summary>
-    /// <param name="throughput">Provisioned throughput to use for the table.</param>
-    member t.InitializeTableAsync(throughput : ProvisionedThroughput) : Async<unit> =
+    /// <param name="throughput">Throughput configuration to use for the table.</param>
+    member t.InitializeTableAsync(throughput : Throughput) : Async<unit> =
         t.InternalCreateOrValidateTableAsync(throughput) |> Async.Ignore
 
     /// <summary>
     /// Asynchronously verifies that the table exists and is compatible with record key schema, throwing if it is incompatible.<br/>
     /// If the table is not present, it is provisioned, with the specified <c>throughput</c>.<br/>
     /// If it is present, and the throughput is not as specified, uses <c>UpdateProvisionedThroughputAsync</c> to update it. <br/>
     /// </summary>
-    /// <param name="throughput">Provisioned throughput to use for the table.</param>
-    member t.ProvisionTableAsync(throughput : ProvisionedThroughput) : Async<unit> = async {
+    /// <param name="throughput">Throughput configuration to use for the table.</param>
+    member t.ProvisionTableAsync(throughput : Throughput) : Async<unit> = async {
         let! tableDescription = t.InternalCreateOrValidateTableAsync(throughput)
-        let provisioned = tableDescription.ProvisionedThroughput
-        if throughput.ReadCapacityUnits <> provisioned.ReadCapacityUnits || throughput.WriteCapacityUnits <> provisioned.WriteCapacityUnits then
-            do! t.UpdateProvisionedThroughputAsync(throughput) }
+        match throughput with
+        | Provisioned p ->
+            let current = tableDescription.ProvisionedThroughput
+            if p.ReadCapacityUnits <> current.ReadCapacityUnits || p.WriteCapacityUnits <> current.WriteCapacityUnits then
+                do! t.UpdateProvisionedThroughputAsync p
+        | OnDemand -> () }
 
     /// <summary>
     ///     Asynchronously verify that the table exists and is compatible with record key schema.
@@ -1015,7 +1034,7 @@ type TableContext<'TRecord> internal
     member t.VerifyTableAsync(?createIfNotExists : bool, ?provisionedThroughput : ProvisionedThroughput) : Async<unit> =
         if createIfNotExists = Some true then
             let throughput = match provisionedThroughput with Some p -> p | None -> ProvisionedThroughput(10L, 10L)
-            t.InitializeTableAsync(throughput)
+            t.InitializeTableAsync(Provisioned throughput)
          else
             t.VerifyTableAsync()
 
@@ -1043,7 +1062,7 @@ type TableContext internal () =
         let context = TableContext<'TRecord>(client, tableName, ?metricsCollector = metricsCollector)
         if createIfNotExists = Some true then
             let throughput = match provisionedThroughput with Some p -> p | None -> ProvisionedThroughput(10L, 10L)
-            do! context.InitializeTableAsync throughput
+            do! context.InitializeTableAsync(Throughput.Provisioned throughput)
         elif verifyTable <> Some false then
             do! context.VerifyTableAsync()
         return context }

tests/FSharp.AWS.DynamoDB.Tests/Utils.fs

@@ -40,10 +40,8 @@ module Utils =
         let client = getDynamoDBAccount()
         let tableName = getRandomTableName()
 
-        member __.CreateContextAndTableIfNotExists<'TRecord>() =
-            let createThroughput = ProvisionedThroughput(10L, 10L)
-            Scripting.TableContext.Initialize<'TRecord>(client, tableName, createThroughput)
+        member _.CreateContextAndTableIfNotExists<'TRecord>() =
+            let throughput = Model.ProvisionedThroughput(readCapacityUnits = 10L, writeCapacityUnits = 10L)
+            Scripting.TableContext.Initialize<'TRecord>(client, tableName, Provisioned throughput)
 
-        interface IDisposable with
-            member __.Dispose() =
-                client.DeleteTableAsync(tableName) |> Async.AwaitTask |> Async.RunSynchronously |> ignore
+        interface IDisposable with member _.Dispose() = client.DeleteTableAsync(tableName) |> Async.AwaitTask |> Async.RunSynchronously |> ignore