logging_util.cpp File Reference

Utilities for logging data. More...

#include <Preferences.h>
#include <NTPClient.h>
#include <TimeStamp.hpp>
#include <SDLogger.hpp>
#include <SDReader.hpp>

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Functions
std::string	cache_retrieve_timestamp ()
void	cache_timestamp (std::string timestamp)
bool	init_data_logger ()
	Initialize logging interfaces.
std::string	get_log_filename (TimeStampParser *)
void	log_to_sd_file (std::string filename, std::string time, std::string topic, std::string message)
void	cache_log_offset (int log_offset)
int	cache_retrieve_log_offset (void)
void	log_to_sd_file (SDLogger *l, std::string time, std::string topic, std::string message)

Variables
Preferences	gator_prefs
	Reference to non-volatile-storage on ESP32.
bool	logging_available = false
	is some logging interface available?
bool	absolute_timestamp_available = false
	is an exact/accurate timestamp available?
bool	logged_relative_data = false
	relatively accurate timestamp used, last exact timestamp + # of minutes/resets elapsed
std::string	time_stamp_to_cache = ""
	the formatted timestamp to write to non-volatile memory for next reset
SDLogger *	logger = NULL
	reads and writes to files
TimeStampBuilder *	tsb = NULL
	builds timestamp strings
TimeStampParser *	tsp = NULL
	parses timestamp strings

Detailed Description

Utilities for logging data.

Summary

Define the helper functions/utilities which have been written for logging data on the Data Gators.

Emphasis is placed on making this as simple to use as possible. Unfortunately it is likely that the implementation is rather difficult to follow due to the number of edge cases covered. These include:

• multiple logging interfaces(SD, WiFi, etc)
• cases where network connection is not available to obtain timestamp for data

Key Functionality

Key functionality includes functions for:

1. caching and retreiving data from NVS
   • timestamps
   • log offsets (calculated from # of resets)
2. constructing file names for logging
3. logging to SD card file

Author

Garrett Wells

Function Documentation

cache_log_offset()

void cache_log_offset

(

int

log_offset

)

Save the reset count.

Parameters

[in]

log_offset

The offset in ticks.

cache_retrieve_log_offset()

int cache_retrieve_log_offset

(

void

)

Retrieves the reset count.

Returns

Number of resets/times the device as booted.

cache_retrieve_timestamp()

std::string cache_retrieve_timestamp

(

)

Retrieve time stamp from non-volatile memory so that it can be used for log file access.

Returns

The string value stored in non-volatile memory, should be expected to be of format produced by TimeStampBuilder

cache_timestamp()

void cache_timestamp

(

std::string

timestamp

)

Cache/update the last known absolute timestamp from the NTPClient to non-volatile memory

Parameters

[in]

timestamp

A timestamp string following the syntax of TimeStampBuilder

get_log_filename()

std::string get_log_filename

(

TimeStampParser *

tsp

)

Generate a file name based on the current time stamp. Should only be called if TimeStampBuilder has been updated.

Parameters

[in]

tsp

TimeStampParser which defines parser for reading the current time stamp from a string.

Returns

a constructed filename log_<month>-<day>-<year>

init_data_logger()

bool init_data_logger

(

)

Initialize logging interfaces.

Perform all initialization necessary before logging any data with log_message to the uSD card.

Returns

bool true if successfully initialized, false for:

• no SD card detected
• some other potential error

log_to_sd_file() [1/2]

void log_to_sd_file	(	SDLogger *	l,
		std::string	time,
		std::string	topic,
		std::string	message
	)

Write an MQTT message to a file on the SD card. Requires a time stamp and filename.

Parameters

[in]	l	The SDLogger instance with all filename and separator information pre-set
[in]	time	The time hr:min:sec+offset that will be written to the log file
[in]	topic	The mqtt topic the data should have been logged to
[in]	message	The mqtt message containing the data we want to save

log_to_sd_file() [2/2]

void log_to_sd_file	(	std::string	filename,
		std::string	time,
		std::string	topic,
		std::string	message
	)

Write an MQTT message to a file on the SD card. Requires a time stamp and filename.

Parameters

[in]	filename	The string file name to log the topic and message to.
[in]	time	string time, formatted according to TimeStampBuilder.
[in]	topic	The topic, according to MQTT format.
[in]	message	The message which contains data. Often JSON object.

Variable Documentation

absolute_timestamp_available

bool absolute_timestamp_available = false

is an exact/accurate timestamp available?

Flag set during initialization, indicates that WiFi connection to NTP for update was obtained.

gator_prefs

Preferences gator_prefs

extern

Reference to non-volatile-storage on ESP32.

Reference to non-volatile-storage on ESP32.

NVS memory access interface.

logged_relative_data

bool logged_relative_data = false

relatively accurate timestamp used, last exact timestamp + # of minutes/resets elapsed

Flag set to indicate that no network connection was available for NTP update to get precise timestamp.

logging_available

bool logging_available = false

is some logging interface available?

Flag showing that some logging interface is available. May be uSD card or MQTT.

time_stamp_to_cache

std::string time_stamp_to_cache = ""

the formatted timestamp to write to non-volatile memory for next reset

The timestamp, last exact timestamp + offset to write to non-volatile storage. This timestamp will be retrieved on next reset and replaced if network connection to NTP available. If NTP not available, then the offset is incremented.