ExAwsConfigurator

Simple json based configurator for AWS SNS/SQS services, use to setup your topics and queues or/and to help to handle topics and queues with prefix or environment based name.

check our documentation

Requirements

• Elixir >= 1.15
• Erlang/OTP >= 26 (required by hackney 4)
• hackney 4.x: if your app declares hackney directly, it must allow ~> 4.9
• ex_aws 2.x (>= 2.7) and ex_aws_sns 2.x (>= 2.3.5, which fixes CVE-2026-47074): if your app pins older versions directly, relax those constraints

Apps that can't meet these (older Elixir/OTP, or pinned to hackney 1.x, ex_aws < 2.7 or ex_aws_sns < 2.3.5) can stay on 1.x (~> 1.5).

Installation

The package can be installed by adding jason to your list of dependencies in mix.exs:

def deps do
  [
    {:ex_aws_configurator, "~> 2.0"}
  ]
end

Configuring ExAws

that package use ExAws to make requests to AWS, you will must to set ex_aws configuration into your config file to:

config :ex_aws,
  access_key_id: "<AWS_ACCESS_KEY_ID>",
  secret_access_key: "<AWS_SECRET_ACCESS_KEY>"

alternatively, you can set AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY on your system environment, see ExAws for more.

Configuring ExAwsConfigurator

look for the config.exs example above:

config :ex_aws_configurator,
  account_id: "000000000000",
  queues: %{
    an_queue: %{
      environment: "an_environment",
      prefix: "queue_prefix",
      region: "us-east-1",
      topics: [:an_topic]
    },
    # ...
  },
  topics: %{
    an_topic: %{environment: "an_environment", prefix: "prefix", region: "us-east-1"},
    another_topic: %{},
    # ...
  }

assuming prod environment, when run ExAwsConfigurator.setup() will:

1. create queue named queue_prefix_an_environment_an_queue on us-east-1 AWS region
2. create topic named prefix_an_environment_an_topic on us-east-1 AWS region
3. create topic named prod_another_topic on default AWS region
4. subscribe queue queue_prefix_an_environment_an_queue into topic prefix_an_environment_an_topic

queue and topic name composition is: prefix + environment + key joined by _.

ExAwsConfigurator.setup() is idempotent: topics and queues that already exist have their mutable attributes (policy, redrive policy, timeouts...) updated to match the configuration, so it is safe to run it on every deploy. It never deletes anything.

External accounts (topics owned by other AWS accounts)

To subscribe a queue to a topic that belongs to another AWS account (another business unit, for example), declare the account under accounts and reference it from the topic:

config :ex_aws_configurator,
  account_id: System.get_env("AWS_ACCOUNT_ID"),   # the default account
  region: "sa-east-1",
  accounts: %{
    health: %{id: System.get_env("AWS_HEALTH_ACCOUNT_ID"), region: "sa-east-1"}
  },
  topics: %{
    subscription_activated: %{prefix: "health_api", account: :health},
    pet_plan_canceled: %{prefix: "health_backoffice", account: :health, on_unauthorized: :warn},
    legacy_topic: %{arn: "arn:aws:sns:sa-east-1:111111111111:some-name-outside-our-convention"}
  },
  queues: %{
    traits_health_plan: %{prefix: "my_app", topics: [:subscription_activated, :pet_plan_canceled]}
  }

• a topic whose account differs from the default one is external: its ARN is composed as usual (prefix + environment + key on the account region), the queue policy allows it as a source, but setup/0 never tries to create it, since it is managed by its owner;
• arn declares a topic by its raw ARN, skipping name composition; the account and region come from the ARN;
• setup/0 subscribes the queue to the external topic, which only works when the topic owner allows sns:Subscribe from your account. If it is denied the setup fails ({:error, :subscriptions}). Set on_unauthorized: :warn on the topic (or globally with config :ex_aws_configurator, on_unauthorized: :warn) to only log a warning instead; the warning contains the policy statement the owner must add.

Account options:

Besides account_id, region, environment, prefix, separator and attributes, topics accept:

ExAwsConfigurator.setup/0 needs, besides the create permissions, sqs:GetQueueUrl, sqs:SetQueueAttributes, sqs:TagQueue, sns:GetTopicAttributes and sns:SetTopicAttributes on your own account.

Telemetry

Every call that touches AWS (SNS.publish/3, SQS.send_message/3, setup/0 and each resource it ensures) is a :telemetry span: [:ex_aws_configurator, :publish | :send_message | :create_topic | :create_queue | :subscribe | :setup] with :start, :stop and :exception events. The metadata names the resource (topic/queue atom, ARN, region, account) and the :stop event carries result (:ok/:error) and the error. See ExAwsConfigurator.Telemetry for the full list.

To get them as metrics, add telemetry_metrics to your deps and append the ready-made definitions to the reporter your app already runs:

# lib/my_app_web/telemetry.ex
def metrics do
  [
    counter("my_app.api.request.count"),
    # ...
  ] ++ ExAwsConfigurator.Telemetry.metrics("my_app")
end

That gives my_app.sns.publish.count/.duration/.exception.count (tagged by topic and result), the same for my_app.sqs.send_message (tagged by queue) and my_app.setup.count/.duration.

Trace propagation

To link the consumer trace to the publisher one, configure a propagator: its headers are added as string message_attributes to every message published or sent. With opentelemetry_api in your deps:

config :ex_aws_configurator,
  propagator: ExAwsConfigurator.Propagator.OpenTelemetry

Any other tracer works through a module implementing ExAwsConfigurator.Propagator or a {module, function, args} returning {name, value} pairs.

On the consumer side (Broadway SQS), ask the producer for the attributes and continue the trace before processing the message:

alias ExAwsConfigurator.Propagator.OpenTelemetry, as: Propagation

# producer options
message_attribute_names: Propagation.header_names()

def handle_message(_processor, message, _context) do
  token = Propagation.extract(message.metadata.message_attributes)

  try do
    OpenTelemetry.Tracer.with_span "orders.process", %{kind: :consumer} do
      process(message)
    end
  after
    OpenTelemetry.Ctx.detach(token)
  end
end

Upgrading from 1.x

• setup/0 updates existing topics and queues instead of failing when their attributes changed. Attributes edited by hand on AWS (a queue policy, for example) are overwritten by what the configuration declares: move any manual adjustment into the configuration (such as an external account) before upgrading;
• setup/0 now fails with {:error, :subscriptions} when a subscription cannot be created (before, subscription errors were ignored);
• setup/0 needs new IAM permissions: sqs:GetQueueUrl, sqs:SetQueueAttributes, sqs:TagQueue, sns:GetTopicAttributes and sns:SetTopicAttributes;
• ExAwsConfigurator.SNS.publish/3 accepts opts forwarded to ExAws.SNS.publish/2 (for example message_attributes). Binaries are published as they are instead of being JSON encoded; maps and lists are still JSON encoded;
• the raw message delivery attribute of a subscription is now set on the topic region;
• ExAwsConfigurator.get_env/1, ExAwsConfigurator.Queue.account_id/1, ExAwsConfigurator.Topic.account_id/1 and ExAwsConfigurator.Config.default_account/0 were removed. ExAwsConfigurator.Config is the only module that reads the application env, and every %Queue{}/%Topic{} it builds carries its %Account{}, so Queue.arn/1, Queue.url/1 and Topic.arn/1 no longer fall back to the global account_id. Use ExAwsConfigurator.get_account(:default) for the default account;
• the global region, environment and on_unauthorized keys accept {:system, "ENV_VAR"}, like account_id already did;
• when the dead letter queue of a queue cannot be created or updated, ExAwsConfigurator.SQS.create_queue/2 now returns that error without touching the queue itself (before, the queue was created anyway, with a redrive policy pointing to a missing dead letter queue). The dead letter queue is available as ExAwsConfigurator.Queue.dead_letter_queue/1 and the redrive policy as ExAwsConfigurator.Queue.redrive_policy/1, already set on the %Queue{} returned by get_queue/1;
• ExAwsConfigurator.setup/0 resolves and validates the whole configuration (ExAwsConfigurator.Config.load/0) before touching AWS: a queue subscribed to a topic that is not configured, an account without id or an invalid arn now raise before anything is created.

if you prefer more control on topics and queues creation you can use the create/subscribe functions separately

ExAwsConfigurator.SNS.create_topic(:an_topic)
ExAwsConfigurator.SQS.create_queue(:an_queue)
ExAwsConfigurator.SQS.subscribe(:an_queue, :an_topic)

Every function of ExAwsConfigurator.SNS and ExAwsConfigurator.SQS accepts either the atom that names the resource in the configuration (the key MUST be present on config.exs) or the %ExAwsConfigurator.Topic{}/%ExAwsConfigurator.Queue{} struct itself, which is handy to drive the adapters from a struct you built or fetched once:

queue = ExAwsConfigurator.get_queue(:an_queue)

ExAwsConfigurator.SQS.create_queue(queue)
for topic <- queue.topics, do: ExAwsConfigurator.SQS.subscribe(queue, topic)

this package provide some helpers to publish or send message too, for complete use please, check our documentation

Contributing

feel free to contribute, issues and pull requests are welcome

License

The MIT License (MIT)

Copyright (c) 2014-2020 CargoSense, Inc.

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.