# AWS clients for Erlang
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[](https://hex.pm/packages/aws_erlang)
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[](https://github.com/aws-beam/aws-erlang/blob/master/LICENSE.md)
[](https://github.com/aws-beam/aws-erlang/commits/master)
:rocket: Create, configure, and manage AWS services from Erlang code. :rocket:
## Features
This repo only holds generated code :exclamation: All non-generated code is included as part of [aws_beam_core](https://github.com/aws-beam/aws_beam_core).
Any changes that need to be made should hence be made through [aws_beam_core](https://github.com/aws-beam/aws_beam_core) or [aws-codegen](https://github.com/aws-beam/aws-codegen) :exclamation:
* Completely generated by [aws-codegen](https://github.com/aws-beam/aws-codegen) from the same JSON descriptions of AWS services used to build the AWS SDKs (See: [aws-sdk-go-v2](https://github.com/aws/aws-sdk-go-v2))
* A clean API separated per service. One module per service.
* Support for most (almost all!) of the AWS services.
* Documentation updated from the official AWS docs.
* Type specs generated from the same JSON descriptions as the SDK
## Usage
Here is an example of listing Amazon Kinesis streams. First of all,
start a shell with `rebar3 shell`, then:
### aws_s3
Here is another example, this time using a _temporary_ client, showing
how to upload a file to _S3_ and how to fetch it back:
```erlang
> Client = aws_client:make_temporary_client(<<"my-access-key-id">>, <<"my-secret-access-key">>, <<"my-token">>, <<"eu-west-1">>).
[...]
> {ok, Content} = file:read_file("/tmp/erlang-logo.png").
[...]
> aws_s3:put_object(Client, <<"my-bucket">>, <<"my-key">>, #{<<"Body">> => Content}).
[...]
> {ok, Response, _} = aws_s3:get_object(Client, <<"my-bucket">>, <<"my-key">>).
[...]
> Content = maps:get(<<"Body">>, Response).
```
Support for creating [Presigned URLs](https://docs.aws.amazon.com/AmazonS3/latest/userguide/ShareObjectPreSignedURL.html) is provided
through the `aws_s3_presigned_url` module.
### aws_kinesis
```erlang
> Client = aws_client:make_client(<<"my-access-key-id">>, <<"my-secret-access-key">>, <<"eu-west-1">>),
[...]
> {ok, Result, _Response} = aws_kinesis:list_streams(Client, #{}),
[...]
> io:format("~p~n", [Result]).
#{<<"HasMoreStreams">> => false,<<"StreamNames">> => []}
```
### AWS RDS IAM Token Creation
Support for creating IAM Tokens (more info here) has been added as part of the aws_rds_iam_token module as part of [aws_beam_core](https://github.com/aws-beam/aws_beam_core).
This allows for easy creation of RDS/Aurora tokens to be used for IAM based authentication instead of username/password combination.
```erlang
> Client = aws_client:make_temporary_client(<<"AccessKeyID">>, <<"SecretAccessKey">>, <<"Token">>, <<"eu-west-1">>).
[...]
> {ok, Url} = aws_rds_iam_token:rds_token_create(Client, <<"db_endpoint">>, 5432, <<"db_user">>).
[...]
```
This token can subsequently be used to connect to the database over IAM.
### AWS S3 Presigned Url
Support for Presigning S3 urls has been added as part of the aws_s3_presigned_url module as part of [aws_beam_core](https://github.com/aws-beam/aws_beam_core).
This allows generating either a get or put presigned s3 url,
which can be used by external clients such as cURL to access (get/put) the object in question.
```erlang
> Client = aws_client:make_temporary_client(<<"AccessKeyID">>, <<"SecretAccessKey">>, <<"Token">>, <<"eu-west-1">>).
[...]
> {ok, Url} = aws_s3_presigned_url:make_presigned_v4_url(Client, put, 3600, <<"bucket">>, <<"key">>)
[...]
```
### retry options
Each API which takes `Options` allows a `retry_options` key and can allow for automatic retries.
Simple provide the following:
`[{retry_options, {exponential_with_jitter, {MaxAttempts, BaseSleepTime, CapSleepTime}}} | <other_options>]`
This implementation is based on [AWS: Exponential Backoff And Jitter](https://aws.amazon.com/blogs/architecture/exponential-backoff-and-jitter/).
## Installation
Simply add the library to your `rebar.config`:
```erlang
{deps, [{aws, "1.1.0", {pkg, aws_erlang}}]}.
```
## Obtaining Credentials
Credentials can be obtained via the separate [aws_credentials](https://github.com/aws-beam/aws_credentials) application, which can be configured to fetch credentials from:
* Erlang environment variables
* OS environment variables
* An AWS credentials file
* ECS task credentials
* EC2 metadata (including v2 - IMDS)
Here is an example on how to obtain credentials:
```erlang
> Credentials = aws_credentials:get_credentials().
[...]
> #{ access_key_id := AccessKeyId
, token := Token
, region := Region
, secret_access_key := SecretAccessKey } = Credentials.
```
The `aws_credentials` application is part of [aws_beam_core](https://github.com/aws-beam/aws_beam_core) and included in this package.
## Development
The service-specific modules are generated using the [aws-codegen](https://github.com/aws-beam/aws-codegen) library from the JSON descriptions of AWS services provided by Amazon.
The rest of the code is manually written and used as support for the generated code.
## Documentation
Unfortunately the docs generated are too big for hexdocs.pm. Hence, the docs can be generated locally using:
```bash
$ rebar3 ex_doc
```
The docs will be available in `./doc`.
## Running Tests
```bash
$ rebar3 eunit
```
```bash
$ docker-compose -f test/docker/docker-compose.yml up -d
$ rebar3 ct
$ docker-compose -f test/docker/docker-compose.yml down
```
## License
Copyright 2015 Jamshed Kakar <jkakar@kakar.ca>
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
