Send email at a validation step or at the end of an interrogation

The email_blast() function is useful for sending an email message that explains the result of a pointblank validation. It is powered by the blastula and glue packages. This function should be invoked as part of the end_fns argument of create_agent(). It's also possible to invoke email_blast() as part of the fns argument of the action_levels() function (i.e., to send multiple email messages at the granularity of different validation steps exceeding failure thresholds).

To better get a handle on emailing with email_blast(), the analogous email_create() function can be used with a pointblank agent object or an x-list obtained from using the get_agent_x_list() function.

email_blast(
  x,
  to,
  from,
  credentials = NULL,
  msg_subject = NULL,
  msg_header = NULL,
  msg_body = stock_msg_body(),
  msg_footer = stock_msg_footer(),
  send_condition = ~TRUE %in% x$notify
)

Arguments

x	A reference to the x-list object prepared internally by the agent. This version of the x-list is the same as that generated via get_agent_x_list(<agent>) except this version is internally generated and hence only available in an internal evaluation context.
to, from	The email addresses for the recipients and of the sender.
credentials	A credentials list object that is produced by either of the blastula::creds(), blastula::creds_anonymous(), blastula::creds_key(), or blastula::creds_file() functions. Please refer to the blastula documentation for information on how to use these functions.
msg_subject	The subject line of the email message.
msg_header, msg_body, msg_footer	Content for the header, body, and footer components of the HTML email message.
send_condition	An expression that should evaluate to a logical vector of length 1. If evaluated as TRUE then the email will be sent, if FALSE then that won't happen. The expression can use x-list variables (e.g., x$notify, x$type, etc.) and all of those variables can be explored using the get_agent_x_list() function. The default expression is ~TRUE %in% x$notify, which results in TRUE if there are any TRUE values in the x$notify logical vector (i.e., any validation step results in a 'notify' condition).

YAML

A pointblank agent can be written to YAML with yaml_write() and the resulting YAML can be used to regenerate an agent (with yaml_read_agent()) or interrogate the target table (via yaml_agent_interrogate()). Here is an example of how the use of email_blast() inside the end_fns argument of create_agent() is expressed in R code and in the corresponding YAML representation.

# R statement
create_agent(
  read_fn = ~ small_table,
  tbl_name = "small_table",
  label = "An example.",
  actions = al,
  end_fns = list(
    ~ email_blast(
      x,
      to = "joe_public@example.com",
      from = "pb_notif@example.com",
      msg_subject = "Table Validation",
      credentials = blastula::creds_key(
        id = "smtp2go"
      ),
    )
  )
) %>%
  col_vals_gt(vars(a), 1) %>%
  col_vals_lt(vars(a), 7) 

# YAML representation
type: agent
read_fn: ~small_table
tbl_name: small_table
label: An example.
lang: en
locale: en
actions:
  warn_count: 1.0
  notify_count: 2.0
end_fns: ~email_blast(x, to = "joe_public@example.com", 
  from = "pb_notif@example.com", msg_subject = "Table Validation",
  credentials = blastula::creds_key(id = "smtp2go"),
  )
embed_report: true
steps:
  - col_vals_gt:
    columns: vars(a)
    value: 1.0
  - col_vals_lt:
    columns: vars(a)
    value: 7.0

Function ID

4-1

See also

Other Emailing: email_create(), stock_msg_body(), stock_msg_footer()

Examples

# Create an `action_levels()` list
# with absolute values for the
# `warn`, and `notify` states (with
# thresholds of 1 and 2 'fail' units)
al <- 
  action_levels(
    warn_at = 1,
    notify_at = 2
  )
  
if (interactive()) {

# Validate that values in column
# `a` from `small_tbl` are always > 1
# and that they are always < 7; first,
# apply the `actions_levels()`
# directive to `actions` and set up
# an `email_blast()` as one of the
# `end_fns` (by default, the email
# will be sent if there is a single
# 'notify' state across all
# validation steps)
agent <-
  create_agent(
    read_fn = ~ small_table,
    tbl_name = "small_table",
    label = "An example.",
    actions = al,
    end_fns = list(
      ~ email_blast(
        x,
        to = "joe_public@example.com",
        from = "pb_notif@example.com",
        msg_subject = "Table Validation",
        credentials = blastula::creds_key(
          id = "smtp2go"
        ),
      )
    )
  ) %>%
  col_vals_gt(vars(a), value = 1) %>%
  col_vals_lt(vars(a), value = 7) %>%
  interrogate()

}

# The above example was intentionally
# not run because email credentials
# aren't available and the `to`
# and `from` email addresses are
# nonexistent

# To get a blastula email object
# instead of eagerly sending the
# message, we can use the 
# `email_create()` function
email_object <-
  create_agent(
    read_fn = ~ small_table,
    tbl_name = "small_table",
    label = "An example.",
    actions = al
  ) %>%
  col_vals_gt(vars(a), value = 5) %>%
  col_vals_lt(vars(a), value = 7) %>%
  interrogate() %>%
  email_create()
#> Warning: The `.dots` argument of `group_by()` is deprecated as of dplyr 1.0.0.