Notification Services

Notification Services (NS) reacts to SubmissionEvent messages emitted by the Fedora repository by composing and dispatching notifications in the form of emails to the participants related to the event.

Runtime Configuration

The runtime configuration for Notification Services (NS) is referenced by the environment variable PASS_NOTIFICATION_CONFIGURATION or a system property named pass.notification.configuration. The value of this environment variable must be a Spring Resource URI, beginning with classpath:/, file:/, or http://.

A sample configuration file is listed below.

Mode

Notification Services (NS) has three runtime modes:

DISABLED: No notifications will be composed or emitted. All JMS messages received by NS will be immediately acknowledged and subsequently discarded.
DEMO: Allows a whitelist, global carbon copy recipient list, and notification templates to be configured distinct from the PRODUCTION mode. Otherwise exactly the same as PRODUCTION.
PRODUCTION: Allows a whitelist, global carbon copy recipient list, and notification templates to be configured distinct from the DEMO mode. Otherwise exactly the same as DEMO.

Configuration elements for both PRODUCTION and DEMO modes may reside in the same configuration file. There is no need to have separate configuration files for a "demo" and "production" instance of NS.

The environment variable PASS_NOTIFICATION_MODE (or its system property equivalent pass.notification.mode) is used to set the runtime mode.

SMTP Server

Notification Services (NS) emits notifications in the form of email. Therefore an SMTP relay must be configured for notification delivery.

PASS_NOTIFICATION_SMTP_HOST (pass.notification.smtp.host): the hostname or IP address of an SMTP mail relay
PASS_NOTIFICATION_SMTP_PORT (pass.notification.smtp.port): the TCP port for SMTP mail relay or submission
PASS_NOTIFICATION_SMTP_USER (pass.notification.smtp.user): optional username for SMTP auth
PASS_NOTIFICATION_SMTP_PASS (pass.notification.smtp.pass): optional password for SMTP auth
PASS_NOTIFICATION_SMTP_TRANSPORT (pass.notification.smtp.transport): valid options are: SMTP, SMTPS, SMTP_TLS

Notification Recipients

The recipient(s) of a notification (e.g. email) is a function of a {Submission, SubmissionEvent} tuple. After the recipient list has been determined, it can be manipulated as discussed below.

Whitelist

Each configuration mode (discussed above) may have an associated whitelist. If the whitelist is empty, all recipients for a given notification will receive an email. If the whitelist is not empty, the recipients for a given notification will be filtered, and only whitelisted recipients will receive the notification. Having a whitelist for the DEMO mode is useful to prevent accidental spamming of end users with test notifications.

Production should use an empty whitelist (i.e. all potential notification recipients are whitelisted).

Global Carbon Copy Support

Each configuration mode (discussed above) may specify one or more "global carbon copy" addresses. These addresses will receive a copy of each email sent by Notification Services (NS). Global carbon copy addresses are implicitly whitelisted; they do not need to be explicitly configured in a whitelist.

Blind carbon copy is also supported.

Here is an example recipient configuration that specifies a global carbon copy and a global blind carbon copy:

"recipient-config": [
    {
      "mode": "DEMO",
      "fromAddress": "[email protected]",
      "global_cc": [
        "[email protected]"
      ],
      "global_bcc": [
        "[email protected]"
      ]          
    }
]

Multiple email addresses may be specified.

Example

For example, let's say that NS is preparing to send a notification to [email protected].

If the runtime mode of NS is DEMO, and:

the DEMO mode has no (or an empty) whitelist, then [email protected] and the global carbon copy address (for the DEMO mode) receives the notification.
the DEMO mode has a whitelist that does not contain [email protected], then only the global carbon copy address receives the notification
the DEMO mode has a whitelist that does contain [email protected], then [email protected] and the global carbon copy address receives the notification
the DEMO mode has a whitelist that does not contain [email protected] and there is no global carbon copy address (for the DEMO mode), then no notification will be dispatched

If the runtime mode of NS is PRODUCTION, and:

the PRODUCTION mode has no (or an empty) whitelist, then [email protected] and the global carbon copy address (for the PRODUCTION mode) receives the notification.
the PRODUCTION mode has a whitelist that does not contain [email protected], then only the global carbon copy address receives the notification
the PRODUCTION mode has a whitelist that does contain [email protected], then [email protected] and the global carbon copy address receives the notification
the PRODUCTION mode has a whitelist that does not contain [email protected] and there is no global carbon copy address (for the PRODUCTION mode), then no notification will be dispatched

Templates

Templates allow the content of notification emails to be customized. There are three templates for every type of notification:

Subject template: used as the content for the subject line of the email notification
Body template: used as the content for the body of the email
Footer template: used as the content for the footer of the email

This allows each part of the email to be templatized independently, or to share a template across notification types (e.g. all notifications could use the same footer template).

Templates can either be specified as in-line configuration values, or they can be specified as Spring Resource URIs referencing the location of the template content. The latter provides the most flexibility, allowing the templates to be managed independent of Notification Services (NS) configuration.

Templates are parameterized by the NS model. This allows for simple variable substitution when rendering the content of an email notification. The template language supported by NS is Mustache, specifically the Handlebars Java implementation. For details on Mustache and Handlebars, check out the Handlebars blog and the Mustache(5) man page. Sample templates are available in the templates/ folder of the notification-services container in pass-docker or in the HandlebarsParameterizerTest class.

The model provided for template parameterization will depend on the version of NS used, because NS composes and parameterizes the model at compile time. Initially NS provides the following model to the Handlebars templating engine:

to: a string containing the email address of the recipient of the notification
cc: a string containing comma delimited email addresses of any carbon copy recipients
from: a string containing the email address of the sender of the notification
resource_metadata: a JSON object containing metadata about the Submission:
- title: the title of the Submission
- journal-title: the name of the journal that the author accepted manuscript is being published to
- volume: the volume of the journal that the author accepted manuscript is being published to
- issue: the issue of the journal that the author accepted manuscript is being published to
- abstract: the abstract of the Submission
- doi: the DOI assigned by the publisher to the author accepted manuscript
- publisher: the name of the publisher
- authors: a JSON array of author objects
event_metadata: a JSON object containing metadata about the SubmissionEvent:
- id: the identifier of the event, a URI to the SubmissionEvent resource
- comment: the comment provided by the preparer or authorized submitter associated with the SubmissionEvent
- performedDate: the DateTime the action precipitating the event was performed
- performedBy: the URI of the User resource responsible for precipitating the event
- performerRole: the role the performedBy user held at the time the event was precipitated
link_metadata: a JSON array of link objects associated with the SubmissionEvent
- each link object has an href attribute containing the URL, and a rel attribute describing its relationship to the SubmissionEvent
- supported rel values are:
  - submission-view: a link to view the Submission resource in the Ember User Interface
  - submission-review: a link to review and approve a Submission in the Ember User Interface
  - submission-review-invite: a link which invites the recipient of the notification to the Ember User Interface, and subsequently presents the review and approve workflow in the Ember User Interface

Environment Variables

Supported environment variables (system property analogs) and default values are:

SPRING_ACTIVEMQ_BROKER_URL (spring.activemq.broker-url): ${activemq.broker.uri:tcp://${jms.host:localhost}:${jms.port:61616}}
SPRING_JMS_LISTENER_CONCURRENCY (spring.jms.listener.concurrency): 4
SPRING_JMS_LISTENER_AUTO_STARTUP (spring.jms.listener.auto-startup): true
PASS_NOTIFICATION_QUEUE_EVENT_NAME (pass.notification.queue.event.name): event
PASS_FEDORA_USER (pass.fedora.user): fedoraAdmin
PASS_FEDORA_PASSWORD (pass.fedora.password): moo
PASS_FEDORA_BASEURL (pass.fedora.baseurl): http://${fcrepo.host:localhost}:${fcrepo.port:8080}/fcrepo/rest/
PASS_ELASTICSEARCH_URL (pass.elasticsearch.url): http://${es.host:localhost}:${es.port:9200}/pass
PASS_ELASTICSEARCH_LIMIT (pass.elasticsearch.limit): 100
PASS_NOTIFICATION_MODE (pass.notification.mode): DEMO
PASS_NOTIFICATION_SMTP_HOST (pass.notification.smtp.host): ${pass.notification.smtp.host:localhost}
PASS_NOTIFICATION_SMTP_PORT (pass.notification.smtp.port): ${pass.notification.smtp.port:587}
PASS_NOTIFICATION_SMTP_USER (pass.notification.smtp.user):
PASS_NOTIFICATION_SMTP_PASS (pass.notification.smtp.pass):
PASS_NOTIFICATION_SMTP_TRANSPORT (pass.notification.smtp.transport): ${pass.notification.smtp.transport:SMTP}
PASS_NOTIFICATION_MAILER_DEBUG (pass.notification.mailer.debug): false
PASS_NOTIFICATION_CONFIGURATION (pass.notification.configuration): classpath:/notification.json
PASS_NOTIFICATION_HTTP_AGENT (pass.notification.http.agent): pass-notification/x.y.z

Example Configuration

An example configuration file is provided below:

{
  "mode": "${pass.notification.mode}",
  "recipient-config": [
    {
      "mode": "DEMO",
      "fromAddress": "[email protected]",
      "global_cc": [
        "[email protected]"
      ],
      "whitelist": [
        "mailto:[email protected]"
      ]
    }
  ],
  "templates": [
    {
      "notification": "SUBMISSION_APPROVAL_INVITE",
      "templates": {
        "SUBJECT": "Approval Invite Subject",
        "BODY": "Approval Invite Body",
        "FOOTER": "classpath:/templates/footer.hbr"
      }
    },
    {
      "notification": "SUBMISSION_APPROVAL_REQUESTED",
      "templates": {
        "SUBJECT": "Approval Requested Subject",
        "BODY": "Approval Requested Body",
        "FOOTER": "classpath:/templates/footer.hbr"
      }
    },
    {
      "notification": "SUBMISSION_CHANGES_REQUESTED",
      "templates": {
        "SUBJECT": "Changes Requested Subject",
        "BODY": "Changes Requested Body",
        "FOOTER": "classpath:/templates/footer.hbr"
      }
    },
    {
      "notification": "SUBMISSION_SUBMISSION_SUBMITTED",
      "templates": {
        "SUBJECT": "Submission Submitted Subject",
        "BODY": "Submission Submitted Body",
        "FOOTER": "classpath:/templates/footer.hbr"
      }
    },
    {
      "notification": "SUBMISSION_SUBMISSION_CANCELLED",
      "templates": {
        "SUBJECT": "Submission Cancelled Subject",
        "BODY": "Submission Cancelled Body",
        "FOOTER": "classpath:/templates/footer.hbr"
      }
    }
  ],
  "smtp": {
    "host": "${pass.notification.smtp.host}",
    "port": "${pass.notification.smtp.port}",
    "smtpUser": "${pass.notification.smtp.user}",
    "smtpPassword": "${pass.notification.smtp.pass}",
    "smtpTransport": "SMTP_TLS"
  },
  "user-token-generator": {
    "key": "BETKPFHWGGDIEWIIYKYQ33LUS4"
  },
  "link-validators": [
    {
      "rels" : [
        "submission-view",
        "submission-review",
        "submission-review-invite"
      ],
      "requiredBaseURI" : "http://example.org",
      "throwExceptionWhenInvalid": true
    }, 
    {
      "rels": ["*"],
      "requiredBaseURI" : "http",
      "throwExceptionWhenInvalid": false
    }
  ]
}

Developers

Design document is here.

The major components of Notification Services (NS) are the model, business logic used to compose a Notification, and the dispatch of Notifications.

Currently each SubmissionEvent received by NS results in the creation of a single Notification, which results in the dispatch of a single email. Multiple recipients (e.g. using CC or BCC email headers) can be specified on the email if needed.

Model

The notification model is below. While email is the natural form of dispatching notifications, the model tries to remain independent of an underlying transport or dispatch mechanism.

Highlights of this model are:

the parameters map: this is the model that is injected into the templating engine
the resouceUri references the PASS resource this notification pertains to
the eventUri references the PASS resource that this notification is responding to
the type is the type of the Notification. In this case, there is a 1:1 correspondence between the SubmissionEvent type and the Notification type.

Notification Types

Notification Type	Description
SUBMISSION_APPROVAL_REQUESTED	Preparer has requested approval of a Submission by an Authorized Submitter
SUBMISSION_APPROVAL_INVITE	Preparer has requested approval of a Submission by an Authorized Submitter who does not have a User in PASS.
SUBMISSION_CHANGES_REQUESTED	Authorized Submitter has requested changes to the submission by the Preparer.
SUBMISSION_SUBMISSION_SUCCESS	Submission was successfully submitted by the Authorized Submitter
SUBMISSION_SUBMISSION_CANCELLED	Submission was cancelled by either the Authorized Submitter or Preparer

Submission State

The state of the Submission vis-a-vis the SubmissionEvent (adapted from the design document).

What happened to the Submission	SubmissionEvent Type	Notification Recipient List
AS Cancelled	CANCELLED	Preparer
AS Submitted	SUBMITTED	Preparer
AS Request Changes	CHANGES_REQUESTED	Preparer
Preparer Cancelled	CANCELLED	AS
Preparer Request Approval	APPROVAL_REQUESTED, APPROVAL_REQUESTED_NEWUSER	AS

AS = Authorized Submitter
Preparer = Proxy who has prepared the submitter on behalf of the AS

Parameters

The parameters map carries simple strings or serialized JSON structures.

TO, CC, BCC, FROM, and SUBJECT are all simple strings
RESOURCE_METADATA, EVENT_METADATA, and LINKS all contain serialized JSON structures
Handlebars, the Mustache-based template engine, can navigate the JSON structures to pull out the desired information for email templates.

Notification Service

The NotificationService is the primary interface that abstracts the business logic associated with composing a Notification and handing it off for dispatch. If future requirements dictate multiple Notifications were to arise from a single SubmissionEvent, DefaultNotificationService would be the starting point for implementing the fan out.

The Composer class does the heavy lifting within the DefaultNotificationService. It is responsible for composing a Notification from the Submission and SubmissionEvent, including:

determining the type of Notification
creating and populating the data structures used in the parameters map
determining the recipients of the Notification, and from whom the Notification should come from

After a Notification has been created and populated, it is sent to the DispatchApi, which returns a unique identifier for each Notification it dispatches.

Dispatch

The Dispatch API accepts a Notification and returns a unique identifier for each Notification it dispatches. The unique identifier is determined by the underlying notification implementation. For example, EmailDispatchImpl returns the SMTP Message-ID. The identifier can be used to associate a Notification with the underlying notification transport.

The Dispatch portion of Notification Services is not concerned with populating the Notification; it expects that business logic to have been performed earlier in the call stack.

Dispatch does have to adapt a Notification to the underlying transport used - in this case, email. This means resolving URIs to recipient email addresses, and invoking the templating engine for composing email subject, body, and footer.

Email Implementation

The only DispatchService implementation is the EmailDispatchImpl, which is composed of three main classes:

Parameterizer: responsible for resolving template content and invoking the templating engine, producing the content for the email subject, body, and footer
EmailComposer: responsible for adapting the Notification to an email (including resolving and setting the from, to, and cc addresses), provided the parameterized templates
Mailer: responsible for actually sending the email to recipients

Templates

Templates are used to customize the subject, body, and footer of email messages that result from a notification. Each notification type has a corresponding template, and the templates and their content are configured in the notification.js configuration file. A sample portion of the configuration is below:

"templates": [
    {
      "notification": "SUBMISSION_APPROVAL_INVITE",
      "templates": {
        "SUBJECT": "Approval Invite Subject",
        "BODY": "Approval Invite Body",
        "FOOTER": "Approval Invite Footer"
      }
    },
    {
      "notification": "SUBMISSION_APPROVAL_REQUESTED",
      "templates": {
        "SUBJECT": "Approval Requested Subject",
        "BODY": "Approval Requested Body",
        "FOOTER": "Approval Requested Footer"
      }
    },
    {
      "notification": "SUBMISSION_CHANGES_REQUESTED",
      "templates": {
        "SUBJECT": "Changes Requested Subject",
        "BODY": "Changes Requested Body",
        "FOOTER": "Changes Requested Footer"
      }
    },
    {
      "notification": "SUBMISSION_SUBMISSION_SUBMITTED",
      "templates": {
        "SUBJECT": "Submission Submitted Subject",
        "BODY": "Submission Submitted Body",
        "FOOTER": "Submission Submitted Footer"
      }
    },
    {
      "notification": "SUBMISSION_SUBMISSION_CANCELLED",
      "templates": {
        "SUBJECT": "Submission Cancelled Subject",
        "BODY": "Submission Cancelled Body",
        "FOOTER": "Submission Cancelled Footer"
      }
    }
  ]

You can see that there is an object identifying each notification type, and for each notification type a SUBJECT, BODY, and FOOTER template may be defined.

The value associated with SUBJECT, BODY, and FOOTER may be in-line content as seen in the example, or it can be a reference to a Spring Resource URI, e.g.:

    {
      "notification": "SUBMISSION_APPROVAL_INVITE",
      "templates": {
        "SUBJECT": "classpath:/templates/submission-approval-subject.txt",
        "BODY": "classpath:/templates/submission-approval-body.txt",
        "FOOTER": "classpath:/templates/submission-approval-footer.txt"
      }
    }

Using Spring Resource URIs to refer to the template location is a more flexible and maintainable way of managing notification templates, because it allows the templates to be updated in place without having to edit the primary configuration file (notification.js) any time a template needs updating. Using Spring Resource URIs also allows template content to be shared across notification types. For example, each notification type could use the same FOOTER content. The CompositeResolver is responsible for determining whether or not the value represents inline content, or if it represents a Spring Resource URI to be resolved.

Notification Services supports Mustache templates, specifically implemented using Handlebars. Each template is injected with the parameters map from the Notification. See above for the documented fields of the parameters map. It is beyond the scope of this README to provide guidance on using Mustache or Handlebars, but there are some examples in pass-docker, and in the HandlebarsParameterizerTest. Both inline template content and referenced template content (i.e. Spring Resource URIs) can be Mustache templates.

Composition

The EmailComposer is responsible for adapting the Notification to an email. This includes:

Resolving Notification recipient URIs to email addresses
- In the case of mailto URIs, the scheme specific part is used as the recipient
- In the case of http or https URIs, they are assumed to reference User resources in the Fedora repository. The URIs are de-referenced and the User.email is used
Applying the email recipient whitelist
Creating the email itself, including the email subject and message body, and encoding.
- the subject and message body are provided to the EmailComposer from the templating engine.

After the EmailComposer has created an email, it is returned to the EmailDispatchImpl for dispatch via SMTP.

Name		Name	Last commit message	Last commit date
Latest commit History 106 Commits
.github/workflows		.github/workflows
dispatch-api		dispatch-api
dispatch-impl		dispatch-impl
logging-aop		logging-aop
notification-boot		notification-boot
notification-impl		notification-impl
notification-integration		notification-integration
notification-model		notification-model
src/main/resources		src/main/resources
.gitignore		.gitignore
.travis.yml		.travis.yml
LICENSE		LICENSE
NOTICE.txt		NOTICE.txt
README.md		README.md
pom.xml		pom.xml
settings-central.tar.enc		settings-central.tar.enc
settings.tar.enc		settings.tar.enc

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Notification Services

Runtime Configuration

Mode

SMTP Server

Notification Recipients

Whitelist

Global Carbon Copy Support

Example

Templates

Environment Variables

Example Configuration

Developers

Model

Notification Types

Submission State

Parameters

Notification Service

Dispatch

Email Implementation

Templates

Composition

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Notification Services

Runtime Configuration

Mode

SMTP Server

Notification Recipients

Whitelist

Global Carbon Copy Support

Example

Templates

Environment Variables

Example Configuration

Developers

Model

Notification Types

Submission State

Parameters

Notification Service

Dispatch

Email Implementation

Templates

Composition

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