From 7ba9ed29453e79abe0bf4660add33492e2425021 Mon Sep 17 00:00:00 2001 From: Greg Date: Sun, 16 Jun 2024 00:37:01 +0900 Subject: [PATCH] update README for v2 --- README.md | 73 ++++++++++++++++++++++--------------------------------- 1 file changed, 29 insertions(+), 44 deletions(-) diff --git a/README.md b/README.md index e4aa6d2..074c47d 100644 --- a/README.md +++ b/README.md @@ -1,10 +1,15 @@ -## dynamo [![GoDoc](https://godoc.org/github.com/guregu/dynamo?status.svg)](https://godoc.org/github.com/guregu/dynamo) -`import "github.com/guregu/dynamo"` +## dynamo [![GoDoc](https://godoc.org/github.com/guregu/dynamo/v2?status.svg)](https://godoc.org/github.com/guregu/dynamo/v2) +`import "github.com/guregu/dynamo/v2"` dynamo is an expressive [DynamoDB](https://aws.amazon.com/dynamodb/) client for Go, with an easy but powerful API. dynamo integrates with the official [AWS SDK v2](https://github.com/aws/aws-sdk-go-v2/). This library is stable and versioned with Go modules. +> [!TIP] +> dynamo v2 is finally released! See [**v2 Migration**](#migrating-from-v1) for tips on migrating from dynamo v1. +> +> If you're using an older version, see: [**dynamo v1 Documentation**](https://pkg.go.dev/github.com/guregu/dynamo). + ### Example ```go @@ -17,7 +22,7 @@ import ( "github.com/aws/aws-sdk-go-v2/aws" "github.com/aws/aws-sdk-go-v2/config" - "github.com/guregu/dynamo" + "github.com/guregu/dynamo/v2" ) // Use struct tags much like the standard JSON library, @@ -45,21 +50,21 @@ func main() { // put item w := widget{UserID: 613, Time: time.Now(), Msg: "hello"} - err = table.Put(w).Run() + err = table.Put(w).Run(ctx) // get the same item var result widget err = table.Get("UserID", w.UserID). Range("Time", dynamo.Equal, w.Time). - One(&result) + One(ctx, &result) // get all items var results []widget - err = table.Scan().All(&results) + err = table.Scan().All(ctx, &results) // use placeholders in filter expressions (see Expressions section below) var filtered []widget - err = table.Scan().Filter("'Count' > ?", 10).All(&filtered) + err = table.Scan().Filter("'Count' > ?", 10).All(ctx, &filtered) } ``` @@ -76,14 +81,14 @@ Please see the [DynamoDB reference on expressions](http://docs.aws.amazon.com/am ```go // Using single quotes to escape a reserved word, and a question mark as a value placeholder. // Finds all items whose date is greater than or equal to lastUpdate. -table.Scan().Filter("'Date' >= ?", lastUpdate).All(&results) +table.Scan().Filter("'Date' >= ?", lastUpdate).All(ctx, &results) // Using dollar signs as a placeholder for attribute names. // Deletes the item with an ID of 42 if its score is at or below the cutoff, and its name starts with G. -table.Delete("ID", 42).If("Score <= ? AND begins_with($, ?)", cutoff, "Name", "G").Run() +table.Delete("ID", 42).If("Score <= ? AND begins_with($, ?)", cutoff, "Name", "G").Run(ctx) // Put a new item, only if it doesn't already exist. -table.Put(item{ID: 42}).If("attribute_not_exists(ID)").Run() +table.Put(item{ID: 42}).If("attribute_not_exists(ID)").Run(ctx) ``` ### Encoding support @@ -182,42 +187,13 @@ This creates a table with the primary hash key ID and range key Time. It creates ### Retrying -Requests that fail with certain errors (e.g. `ThrottlingException`) are [automatically retried](https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Programming.Errors.html#Programming.Errors.RetryAndBackoff). -Methods that take a `context.Context` will retry until the context is canceled. -Methods without a context will use the `RetryTimeout` global variable, which can be changed; using context is recommended instead. - -#### Limiting or disabling retrying - -The maximum number of retries can be configured via the `MaxRetries` field in the `*aws.Config` passed to `dynamo.New()`. A value of `0` will disable retrying. A value of `-1` means unlimited and is the default (however, context or `RetryTimeout` will still apply). - -```go -db := dynamo.New(session, &aws.Config{ - MaxRetries: aws.Int(0), // disables automatic retrying -}) -``` - -#### Custom retrying logic - -If a custom [`request.Retryer`](https://pkg.go.dev/github.com/aws/aws-sdk-go/aws/request#Retryer) is set via the `Retryer` field in `*aws.Config`, dynamo will delegate retrying entirely to it, taking precedence over other retrying settings. This allows you to have full control over all aspects of retrying. - -Example using [`client.DefaultRetryer`](https://pkg.go.dev/github.com/aws/aws-sdk-go/aws/client#DefaultRetryer): - -```go -retryer := client.DefaultRetryer{ - NumMaxRetries: 10, - MinThrottleDelay: 500 * time.Millisecond, - MaxThrottleDelay: 30 * time.Second, -} -db := dynamo.New(session, &aws.Config{ - Retryer: retryer, -}) -``` +As of v2, dynamo relies on the AWS SDK for retrying. See: [**Retries and Timeouts documentation**](https://aws.github.io/aws-sdk-go-v2/docs/configuring-sdk/retries-timeouts/) for information about how to configure its behavior. ### Compatibility with the official AWS library -dynamo has been in development before the official AWS libraries were stable. We use a different encoder and decoder than the [dynamodbattribute](https://godoc.org/github.com/aws/aws-sdk-go/service/dynamodb/dynamodbattribute) package. dynamo uses the `dynamo` struct tag instead of the `dynamodbav` struct tag, and we also prefer to automatically omit invalid values such as empty strings, whereas the dynamodbattribute package substitutes null values for them. Items that satisfy the [`dynamodbattribute.(Un)marshaler`](https://godoc.org/github.com/aws/aws-sdk-go/service/dynamodb/dynamodbattribute#Marshaler) interfaces are compatibile with both libraries. +dynamo has been in development before the official AWS libraries were stable. We use a different encoder and decoder than the [dynamodbattribute](https://pkg.go.dev/github.com/jviney/aws-sdk-go-v2/service/dynamodb/dynamodbattribute) package. dynamo uses the `dynamo` struct tag instead of the `dynamodbav` struct tag, and we also prefer to automatically omit invalid values such as empty strings, whereas the dynamodbattribute package substitutes null values for them. Items that satisfy the [`dynamodbattribute.(Un)marshaler`](https://pkg.go.dev/github.com/jviney/aws-sdk-go-v2/service/dynamodb/dynamodbattribute#Marshaler) interfaces are compatibile with both libraries. -In order to use dynamodbattribute's encoding facilities, you must wrap objects passed to dynamo with [`dynamo.AWSEncoding`](https://godoc.org/github.com/guregu/dynamo#AWSEncoding). Here is a quick example: +In order to use dynamodbattribute's encoding facilities, you must wrap objects passed to dynamo with [`dynamo.AWSEncoding`](https://godoc.org/github.com/guregu/dynamo/v2#AWSEncoding). Here is a quick example: ```go // Notice the use of the dynamodbav struct tag @@ -229,12 +205,21 @@ type book struct { err := db.Table("Books").Put(dynamo.AWSEncoding(book{ ID: 42, Title: "Principia Discordia", -})).Run() +})).Run(ctx) // When getting an item you MUST pass a pointer to AWSEncoding! var someBook book -err := db.Table("Books").Get("ID", 555).One(dynamo.AWSEncoding(&someBook)) +err := db.Table("Books").Get("ID", 555).One(ctx, dynamo.AWSEncoding(&someBook)) ``` +### Migrating from v1 + +The API hasn't changed much from v1 to v2. Here are some migration tips: + +- All request methods now take a [context](https://go.dev/blog/context) as their first argument. +- Retrying relies on the AWS SDK configuration, see: [Retrying](#retrying). + - Transactions won't retry TransactionCanceled responses by default anymore, make sure you configure that if you need it. +- [Compatibility with the official AWS library](#compatibility-with-the-official-aws-library) uses v2 interfaces instead of v1. + ### Integration tests By default, tests are run in offline mode. In order to run the integration tests, some environment variables need to be set.