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Survey Logger Class

survey_logger.Rd

R6 Class providing dual logging functionality for Shiny survey applications: console messaging and database logging of survey metadata.

Details

The logger provides two distinct logging mechanisms:

Console Logging (log_message):

  • Immediate color-coded console output for app messages, warnings, and errors

  • No database persistence - console only

  • Supports custom zones/contexts for message categorization

Database Logging (log_entry):

  • Queued logging of survey metadata to database table

  • Tracks survey completion metrics (timing, errors, SQL statements)

  • Uses batch processing with automatic queue management

  • Only logs database errors after survey is loaded (conditional logging)

Key Features:

  • Dual-purpose logging: console messages + database survey metadata

  • Uses main application connection for database operations

  • Efficient batch database writes with automatic queue processing

  • Immediate console feedback with color coding and zone support

  • Database connection health monitoring

  • SQL statement tracking for database error debugging

Console Message Types

  • INFO: Regular informational messages (green console output)

  • WARN: Warning messages (yellow console output)

  • ERROR: Error messages (red console output)

Public fields

log_table

Character string specifying the database table for logs

session_id

Character string containing unique session identifier

table_name

Character string identifying the current table

survey_loaded

Logical flag indicating if a survey has been successfully loaded

suppress_logs

Logical flag to suppress console output

queue

data.frame containing queued messages for batch processing

last_sql

Character string containing the last executed SQL statement

Methods

Public methods

Method new()

Initialize a new survey logger instance

Usage

survey_logger$new(log_table, session_id, table_name, echo = TRUE)

Arguments

log_table

Character string specifying logging table name

session_id

Character string containing session identifier

table_name

Character string identifying the table

echo

Logical flag to display console output. Default: TRUE

Method update_table_name()

Update the table name for this logger instance

Usage

survey_logger$update_table_name(table_name)

Arguments

table_name

Character string identifying the new table name

Returns

Invisible NULL

Method mark_survey_loaded()

Mark the survey as loaded to enable error logging

Usage

survey_logger$mark_survey_loaded()

Returns

Invisible NULL

Method update_last_sql()

Update the last SQL statement executed

Usage

survey_logger$update_last_sql(sql)

Arguments

sql

Character string containing the SQL statement

Returns

Invisible NULL

Method log_entry()

Queue a log entry for database insert (only for loaded surveys)

Usage

survey_logger$log_entry(
  table_id,
  message = NULL,
  ip_address = NULL,
  duration_load = NULL,
  duration_complete = NULL,
  duration_save = NULL,
  sql = NULL,
  force_log = FALSE
)

Arguments

table_id

Integer ID from the table

message

Character string containing error message (only for DB errors after survey loaded)

ip_address

Character string containing client IP address

duration_load

Numeric time spent loading (seconds)

duration_complete

Numeric time spent completing survey (seconds)

duration_save

Numeric time spent saving (seconds)

sql

Character string containing the SQL that failed (only for errors)

force_log

Logical flag to force logging even if survey not loaded (internal use)

Returns

Invisible NULL

Method log_message()

Helper method for simple console logging (no database)

Usage

survey_logger$log_message(message, type = "INFO", zone = "DEFAULT")

Arguments

message

Character string containing message to log

type

Character string specifying message type (INFO/WARN/ERROR)

zone

Character string specifying the logging zone/context (default: "DEFAULT")

Returns

Invisible NULL

Method clone()

The objects of this class are cloneable with this method.

Usage

survey_logger$clone(deep = FALSE)

Arguments

deep

Whether to make a deep clone.