# isatdatapro-microservices This library provides a microservices framework for interacting with Inmarsat's IsatData Pro satellite IoT messaging service. Messages sent from or to remote devices via satellite connectivity are stored in a database along with metadata about the satellite modem configuration and properties. A Node.js singleton emitter is also supported to publish events such as message delivery, new modems sending data, and API/server errors. [Documentation](https://inmarsat.github.io/isatdatapro-microservices/) ## Installation ``` npm i isatdatapro-microservices ``` ## Configuration The library relies on the following environment variable settings. The database particulars are configured as environment variables: * **``DB_TYPE``** supports ``azureCosmos`` or ``mysql`` For [Cosmos DB](./module-repositories_azureCosmosRepository-DatabaseContext.html): * **``COSMOS_DB_HOST``** is the Azure URL for the Cosmos DB * **``COSMOS_DB_PASS``** is the password for the Cosmos DB * **``COSMOS_DB_NAME``** is the database name e.g. IsatDataPro * **``COSMOS_DB_CONTAINER``** is the container name e.g. Main * **``COSMOS_DB_PARTITION``** is the partition name i.e. ``category`` * **``COSMOS_DB_THROUGHPUT``** is the default throughput e.g. 400 For [MySQL](./module-repositories_mysqlRepository-DatabaseContext.html): * **``MYSQL_DB_HOST``** is the MySQL host name e.g. localhost * **``MYSQL_DB_USER``** is the access name e.g. root * **``MYSQL_DB_PASS``** is the password * **``MYSQL_DB_NAME``** is the name of the database e.g. IsatDataPro Encryption of Mailbox passwords uses a secret defined in an environment variable: * **``MAILBOX_SECRET``** is a string used as the encryption key The following environment variables are optional with defaults in the code: * **``SATELLITE_HISTORY_HOURS=48``** the number of hours to go back on first API call for message/status retrieval * **``DB_TTL_DAYS_API=7``** time to live for ApiCallLog entries in database * **``DB_TTL_DAYS_MSG=90``** time to live for message entries in database ## Infrastructure ### Database #### Models The database supports the following model concepts: * [**SatelliteGateway**](./SatelliteGateway.html) represents the API server operated by Inmarsat or another authorized network operator. ``category = 'satellite_gateway'`` with ``name`` as the model-unique key. * [**Mailbox**](./Mailbox.html) represents an account providing authentication and segregation of customer data access. These are configured with authentication credentials, where the password component is [encrypted] for storage. ``category = 'mailbox'`` with ``mailboxId`` as the model-unique key. * [**Mobile**](./Mobile.html) represents a satellite modem associated with a remote asset/device and supports various metadata related to configuration, queried location and diagnostic information. ``category = 'mobile'`` with ``mobileId`` as the model-unique key. * [**MessageReturn**](./MessageReturn.html) represents mobile-originated (aka *Return*) data, typically device telemetry or responses to low-level modem commands. These messages contain data as raw binary and/or JSON structures depending on whether a *Message Definition File* is provisioned on the *Mailbox*. ``category = 'message_return'`` with ``messageId`` as the model-unique key. * [**MessageForward**](./MessageForward.html) represents mobile-terminated (aka *Forward*) data, typically commands or small files sent to the device from a cloud-based application. These messages contain data as raw binary and/or JSON structures depending on how they are submitted and whether a *Message Definition File* is provisioned on the *Mailbox*. ``category = 'message_forward'`` with ``messageId`` as the model-unique key. * [**ApiCallLog**](./ApiCallLog.html) record the low-level API transactions to the Inmarsat server including various metadata used as a "high water mark" for message retrieval and for diagnostic purposes. ``category = 'api_call_log'`` with ``callTimeUtc`` as the model-unique key. #### Storage Data storage architecture is dependent on the database type. For example Azure Cosmos DB is a flat structure using a category tag for search, while MySQL initializes a table for each model type. Model property keys use snake_case when stored in the database, which are translated to camelCase when retrieved via ``find()`` ApiCallLog and Messages include a *time-to-live* (**ttl**) class property with units in seconds. When using Cosmos DB, this property should automatically remove aged data to keep database size smaller. For MySQL, the user can implement a periodic check with the *removeAged* method. #### Methods The principle methods for accessing the database are: 1. **``initialize()``** ensures the database infrastructure is in place, creating it if running for the first time, and instantiates the connection. 2. **``find()``** retrieves the specified model based on its category and optional filter criteria. 3. **``upsert()``** adds a new model or updates an existing one based on its model- unique key. 4. **``close()``** terminates the connection after use. ### Encryption The encryption function is primarily for illustrative purposes using AES-256 based on a secret/key stored as an environment variable ``MAILBOX_SECRET``. The encryption is used at rest when storing Mailbox password in the database, then decrypted to pass as a credential in the relevant API call, which in turn is encrypted by TLS in transit. ### Event Handler The [``eventHandler.emitter``](./module-eventHandler.html) is implemented as a Node *events* emitter intended for use as a singleton, which emits the following dependent on the microservice in play: * **NewMobile** includes metadata about a new satellite modem the first time a return message is received causing that Mobile to be added to the database. * **NewReturnMessage** includes message content and metadata whenever a new return messsage is received from any modem. * **NewForwardMessage** includes content and metadata when a forward message is submitted via the ``submitForwardMessages`` microservice. * **ForwardMessageStateChange** triggers when a submitted forward message's state changes e.g. to DELIVERED or FAILED. * **OtherClientForwardSubmission** triggers when a status is retrieved for a forward message that was *not* submitted via the ``submitForwardMessages`` microservice. * **ApiError** triggers when an error code is returned by the Inmarsat API. * **ApiOutage** triggers when the Inmarsat API becomes non-responsive. API state is maintained in the database ``SatelliteGateway`` property ``alive``. * **ApiRecovery** triggers when the Inmarsat API becomes responsive after an outage. ### Logging A Winston [logger](./module-logging.html) is included to provide JSON-structured logs with a standard format and UTC timestamp for troubleshooting. A proxy logger is exposed for convenience use by applications using the library. ### Message Codecs All IsatData Pro modems support a standard set of basic remote operations referred to as [*Core Modem Messages*](./module-messageCodecs_coreModem.html) which are normally presented as JSON-structured data on the API and contain metadata about the modem. The ``getReturnMessages`` microservice parses these standard messages to populate *Mobile* metadata in the database. Additionally the ``submitForwardMessages`` microservice accepts shorthand remote commands/parameters which use the message codec to encode the message to send over the air. The JSON-structured data employs a so-called *common message format* supporting various data types encoded as binary data over the satellite link. To make use of [``commonMessageFormat``](./module-messageCodecs_commonMessageFormat.html) for application messages, contact your Inmarsat representative to discuss the concept of *Message Definition File* in your application. ## Microservices The microservices and eventHandler emitter are the primary aspects exposed by this library. Before using the microservices it is necessary to "provision" at least one *SatelliteGateway* (API URL) and one *Mailbox* with valid access credentials. * [**``getReturnMessages``**](./module-getReturnMessages.html) is intended to run periodically (e.g. every 15 seconds) to retrieve new messages coming in from all modems accessed by the provisioned *Mailbox*(es). Events emitted include ``NewReturnMessage``, ``NewMobile``. * [**``submitForwardMessages``**](./module-submitForwardMessages.html) is called destined to a specific *mobileId* with specific commands, an array of decimal-coded bytes *payloadRaw* or an application-specific *payloadJson*. Events emitted include ``NewForwardMessage``. * [**``getForwardStatuses``**](./module-getForwardStatuses.html) is intended to be run periodically, in particular following the use of ``submitForwardMessages`` to monitor the progression of commands or mobile-terminated data. Events emitted include ``ForwardMessageStateChange``, ``OtherClientForwardSubmission``. * [**``getForwardMessages``**](./module-getForwardMessages.html) is intended to be used following a ``OtherClientForwardSubmission`` event, to retrieve the content of a message submitted by a means other than ``submitForwardMessages`` (which generally implies another API client is accessing the Mailbox in parallel). * [**``updateMailbox``**](./module-updateMailbox.html) is used to add a *Mailbox* to the database which will subsequently be polled by ``getReturnMessages`` and accessible for ``submitForwardMessages``. A *Mailbox* is the parent of one or more *Mobile*(s). * [**``updateSatelliteGateway``**](./module-updateSatelliteGateway.html) is used to add a *SatelliteGateway* to the database as the parent of one or more *Mailbox*(es). * [**``getMobiles``**](./module-getMobiles.html) may be used to retrieve the list of *Mobile*(s) metadata from the provisioned *Mailbox*(es). This operation is useful if a given Mobile has not yet sent any return messages.