MongoosePush is a simple, RESTful service written in Elixir, providing ability to send push notifications to FCM (Firebase Cloud Messaging) and/or APNS (Apple Push Notification Service) via their HTTP/2 API.

We provide already built MongoosePush images. If you just want to use it, then all you need is docker, FCM app token and/or APNS app certificates. In case of certificates and token you need to setup the following directory structure:

• priv/
  • ssl/
    • rest_cert.pem - The HTTP endpoint certificate
    • rest_key.pem - private key for the HTTP endpoint certificate (has to be unencrypted)
  • apns/
    • prod_cert.pem - Production APNS app certificate
    • prod_key.pem - Production APNS app certificate's private key (has to be unencrypted)
    • dev_cert.pem - Development APNS app certificate
    • dev_key.pem - Development APNS app certificate's private key (has to be unencrypted)
  • fcm/
    • token.json - FCM service account JSON file

FCM JSON file can be generated by Firebase console (https://console.firebase.google.com). Go to your project -> Project Settings -> Service accounts -> Generate new private key
Assuming that you have the priv directory with all ceriticates and fcm token in current directory, then you may start MongoosePush with the following command:

docker run -v `pwd`/priv:/opt/app/priv \
  -e PUSH_HTTPS_CERTFILE="/opt/app/priv/ssl/rest_cert.pem" \
  -e PUSH_HTTPS_KEYFILE="/opt/app/priv/ssl/rest_key.pem" \
  -it --rm mongooseim/mongoose-push:latest

Building docker is really easy, just type:

MIX_ENV=prod mix do deps.get, certs.dev, docker.build, docker.release

As a result of this command you get access to mongoose_push:release docker image. You may run it by typing:

docker run -it --rm mongoose_push:release foreground

The docker image that you have just built, exposes the port 8443 for the HTTP API of MongoosePush. It contains a VOLUME for path /opt/app - it is handy for injecting APNS and HTTP API certificates since by default the docker image comes with test, self-signed certificates.

The docker image of MongoosePush contains common, basic configuration that is generated from config/prod.exs. All useful options may be overridden via system environmental variables. Below there's a full list of the variables you may set while running docker (via docker -e switch), but if there's something you feel, you need to change other then that, then you need to prepare your own config/prod.exs before image build.

Environmental variables to configure production release:

• PUSH_HTTPS_BIND_ADDR - Bind IP address of the HTTP endpoint. Default value in prod release is "127.0.0.1", but docker overrides this with "0.0.0.0"
• PUSH_HTTPS_PORT - The port of the MongoosePush HTTP endpoint. Please note that docker exposes only 8443 port, so changing this setting is not recommended
• PUSH_HTTPS_KEYFILE - Path to a PEM keyfile used for HTTP endpoint
• PUSH_HTTPS_CERTFILE - Path to a PEM certfile used for HTTP endpoint
• PUSH_HTTPS_ACCEPTORS - Number of TCP acceptors to start

• PUSH_LOGLEVEL - debug/info/warn/error - Log level of the application. info is the default one
• PUSH_FCM_ENABLED - true/false - Enable or disable FCM support. Enabled by default
• PUSH_APNS_ENABLED - true/false - Enable or disable APNS support. Enabled by default

• PUSH_FCM_ENDPOINT - Hostname of FCM service. Set only for local testing. By default this option points to the Google's official hostname
• PUSH_FCM_APP_FILE - Path to FCM service account JSON file. For details look at Running from DockerHub section
• PUSH_FCM_POOL_SIZE - Connection pool size for FCM service

• PUSH_APNS_DEV_ENDPOINT - Hostname of APNS service. Set only for local testing. By default this option points to the Apple's official hostname
• PUSH_APNS_DEV_CERT - Path Apple's development certfile used to communicate with APNS
• PUSH_APNS_DEV_KEY - Path Apple's development keyfile used to communicate with APNS
• PUSH_APNS_DEV_USE_2197 - true/false - Enable or disable use of alternative 2197 port for APNS connections in development mode. Disabled by default
• PUSH_APNS_DEV_POOL_SIZE - Connection pool size for APNS service in development mode
• PUSH_APNS_DEV_DEFAULT_TOPIC - Default APNS topic to be set if the client app doesn't specify it with the API call. If this option is not set, MongoosePush will try to extract this value from the provided APNS certificate (the first topic will be assumed default). DEV certificates normally don't provide any topics, so this option can be safely left unset

• PUSH_APNS_PROD_ENDPOINT - Hostname of APNS service. Set only for local testing. By default this option points to the Apple's official hostname
• PUSH_APNS_PROD_CERT - Path Apple's production certfile used to communicate with APNS
• PUSH_APNS_PROD_KEY - Path Apple's production keyfile used to communicate with APNS
• PUSH_APNS_PROD_USE_2197 - true/false - Enable or disable use of alternative 2197 port for APNS connections in production mode. Disabled by default
• PUSH_APNS_PROD_POOL_SIZE - Connection pool size for APNS service in production mode
• PUSH_APNS_PROD_DEFAULT_TOPIC - Default APNS topic to be set if the client app doesn't specify it with the API call. If this option is not set, MongoosePush will try to extract this value from the provided APNS certificate (the first topic will be assumed default)

• Elixir 1.5+ (http://elixir-lang.org/install.html)
• Erlang/OTP 19.3+

  NOTE: Some Erlang/OTP 20.x releases / builds contain TLS bug that prevents connecting to APNS servers. When building with this Erlang version, please make sure that MongoosePushRuntimeTest test suite passes. It is however highly recommended to build MongoosePush with Erlang/OTP 21.x.

• Rebar3 (just enter mix local.rebar)

Build step is really easy. Just type in root of the repository:

MIX_ENV=prod mix do deps.get, compile, certs.dev, distillery.release

After this step you may try to run the service via:

_build/prod/rel/mongoose_push/bin/mongoose_push console

Yeah, I know... It crashed. Running this service is fast and simple but unfortunately you can't have push notifications without properly configured FCM and/or APNS service. So, lets configure it!

The whole configuration is contained in file config/{prod|dev|test}.exs depending on which MIX_ENV you will be using. You should use MIX_ENV=prod for production installations and MIX_ENV=dev for your development. Anyway, lets take a look on config/dev.exs, part by part.

config :maru, MongoosePush.Router,
    versioning: [
        using: :path
    ],
    https: [
        ip: {127, 0, 0, 1},
        port: 8443,
        keyfile: "priv/ssl/fake_key.pem",
        certfile: "priv/ssl/fake_cert.pem",
        otp_app: :mongoose_push
    ]

This part of configuration relates only to HTTP endpoints exposed by MongoosePush. Here you can set a bind IP adress (option: ip), port and paths to your HTTP TLS certificates. You should ignore other options unless you know what you're doing (to learn more, explore maru's documentation).

You may entirely skip the maru config entry to disable HTTP API and just use this project as an Elixir library.

Lets take a look at sample FCM service configuration:

config :mongoose_push, fcm: [
    default: [
        appfile: "path/to/token.json",
        endpoint: "localhost",
        pool_size: 5,
        mode: :prod
    ]
  ]

This is a definition of a pool - each pool has a name and configuration. It is possible to have multiple named pools with different configuration, which includes pool size, environment mode etc. Currently the only reason you may want to do this is to create separate production and development pools which may be selected by an HTTP client by specifying matching :mode in their push request.

Each FCM pool may be configured by setting the following fields:

• appfile (required) - path to FCM service account JSON file. Details on how to get one are in Running from DockerHub section
• pool_size (required) - maximum number of used HTTP/2 connections to google's service
• mode (either :prod or :dev) - pool's mode. The HTTP client may select pool used to push a notification by specifying matching option in the request
• endpoint (optional) - URL override for FCM service. Useful mainly in tests

You may entirely skip the FCM config entry to disable FCM support.

Lets take a look at sample APNS service configuration:

config :mongoose_push, apns: [
   dev: [
     cert: "priv/apns/dev_cert.pem",
     key: "priv/apns/dev_key.pem",
     mode: :dev,
     use_2197: false,
     pool_size: 5
   ],
   prod: [
     cert: "priv/apns/prod_cert.pem",
     key: "priv/apns/prod_key.pem",
     mode: :prod,
     use_2197: false,
     pool_size: 5
   ]
 ]

Just like for FCM, at the top level we can specify the named pools that have different configurations. For APNS this is especially useful since Apple delivers different APS certificates for development and production use. The HTTP client can select a named pool by providing a matching :mode in the HTTP request.

Each APNS pool may be configured by setting the following fields:

• cert (required) - relative path to APNS PEM certificate issued by Apple. This certificate have to be somewhere in priv directory
• key (required) - relative path to PEM private key for APNS certificate issued by Apple. This file have to be somewhere in priv directory
• pool_size (required) - maximum number of used HTTP/2 connections to google's service
• mode (either :prod or :dev) - pool's mode. The HTTP client may select pool used to push a notification by specifying matching option in the request
• endpoint (optional) - URL override for APNS service. Useful mainly in tests
• use_2197 (optional true or false) - whether use alternative port for APNS: 2197

You may entirely skip the APNS config entry to disable APNS support.

If you happen to have APNS files in pkcs12 format (.p12 or .pfx extenstion) you need to convert them to PEM format which is understood by MongoosePush. Belowe you can find sample openssl commands which may be helpful.

openssl pkcs12 -in YourAPNS.p12 -out YourCERT.pem -nodes -nokeys

openssl pkcs12 -in YourAPNS.p12 -out YourKEY.pem -nodes -nocerts

If for some reason you need Swagger spec for this RESTful service, there is a swagger endpoint available via an HTTP path /swagger.json

There is only one endpoint at this moment:

• POST /v2/notification/{device_id}

As you can imagine, {device_id} should be replaced with device ID/Token generated by your push notification provider (FCM or APNS). The notification should be sent as JSON payload of this request. Minimal JSON request could be like this:

{
  "service": "apns",
  "alert":
    {
      "body": "notification's text body",
      "title": "notification's title"
    }
}

The full list of options contains the following:

• service (required, apns or fcm) - push notifications provider to be used for this notification
• mode (optional, prod (default) or dev) - allows for selecting named pool configured in MongoosePush
• priority (optional) - Either normal or high. Those values are used without changes for FCM. For APNS however, normal maps to priority 5, while high maps to priority 10. Please refer to FCM / APNS documentation for more details on those values. By default priority is not set at all, therefore the push notification service decides which value is used by default.
• time_to_live (optional) - Maximum lifespan of an FCM notification. For more details, please, refer to the official FCM documentation.
• mutable_content (optional, true / false (default)) - Only applicable to APNS. Sets "mutable-content=1" in APNS payload.
• topic (optional, APNS specific) - if APNS certificate configured in MongoosePush allows for multiple applications, this field selects the application. Please refer to APNS documentation for more datails
• data (optional) - custom JSON structure sent to the target device. For APNS, all keys form this stucture are merged into highest level APS message (the one that holds 'aps' key), while for FCM the whole data json stucture is sent as FCM's data payload along with notification.
• alert (optional) - JSON stucture that if provided will send non-silent notification with the following fields:
  • body (required) - text body of notification
  • title (required) - short title of notification
  • click_action (optional) - for FCM its activity to run when notification is clicked. For APNS its category to invoke. Please refer to Android/iOS documentation for more details about this action
  • tag (optional, FCM specific) - notifications aggregation key
  • badge (optional, APNS specific) - unread notifications count
  • sound (optional) - sound that should be play when notification arrives. Please refer to FCM / APNS documentation for more details.

Please note that either alert and data has to be provided (also can be both). If you only specify alert, the request will result in classic, simple notification. If you only specify data, the request will result in "silent" notification, i.e. the client will receive the data and will be able to decide whether notification shall be shown and how should be shown to the user. If you specify both alert and data, target device will receive both notification and the custom data payload to process.

MongoosePush supports metrics based on elixometer. In order to enable metrics, you need to add an elixometer configuration in the config file matching your release type (or simply sys.config when you need this on already released MongoosePush). The following example config will enable simplest reporter - TTY (already enabled in :dev environment):

config :exometer_core, report: [reporters: [{:exometer_report_tty, []}]]
config :elixometer, reporter: :exometer_report_tty,
     env: Mix.env,
     metric_prefix: "mongoose_push"

The example below on the other hand will enable graphite reporter (replace GRAPHITE_OPTIONS with a list of options for graphite):

Before making a release:

config :exometer_core, report: [reporters: [{:exometer_report_graphite, GRAPHITE_OPTIONS}]]
config :elixometer, reporter: :exometer_report_graphite,
      env: Mix.env,
      metric_prefix: "mongoose_push"

or if you modify an existing release (sys.config):

{exometer_core,[{report, [{reporters, [{exometer_report_graphite, GRAPHITE_OPTIONS}]}]}]},
{elixometer,
    [{reporter, exometer_report_graphite},
     {env, prod},
     {metric_prefix, <<"mongoose_push">>}]},

If you use dockerized MongoosePush, you need to do the following:

• Start MongoosePush docker, let's assume its name is mongoose_push
• Run: docker cp mongoose_push:/opt/app/var/sys.config sys.config on you docker host (this will get the current sys.config to your ${CWD})
• Modify the sys.config as you see fit (for metrics, see above)
• Stop MongoosePush docker container and restart it with the modified sys.config as volume in /opt/app/sys.config (yes, this is not the path we used to copy this file from, this is an override)

The following metrics are available:

• mongoose_push.${METRIC_TYPE}.push.${SERVICE}.${MODE}.error.all
• mongoose_push.${METRIC_TYPE}.push.${SERVICE}.${MODE}.error.${REASON}
• mongoose_push.${METRIC_TYPE}.push.${SERVICE}.${MODE}.success

Where:

• METRIC_TYPE is either timers or spirals
• SERVICE is either fcm or apns
• MODE is either prod or dev
• REASON is an arbitrary error reason term