* Location Logging
This document was created by Steven Baltakatei Sandoval on
-<2020-06-29 Mon 12:14> under a [[https://creativecommons.org/licenses/by-sa/4.0/][Creative Commons BY-SA 4.0 license]]. It
-was updated by Steven Baltakatei Sandoval on <2020-06-29 Mon 22:06>.
+~2020-06-29T12:14Z~ under a [[https://creativecommons.org/licenses/by-sa/4.0/][Creative Commons BY-SA 4.0 license]]. It
+was updated by Steven Baltakatei Sandoval on ~2020-07-23T21:49Z~
#+TITLE: Ninfacyzga-01 Manual
#+AUTHOR: Steven Baltakatei Sandoval
-#+DATE: 2020-06-29T22:16Z
#+EMAIL: baltakatei@gmail.com
** Narrative
Ninfacyzga-01 records (logs) its position in time and space using a
**** PiZ UpTime 2.0
See the [[https://alchemy-power.com/piz-uptime-2-0/][OEM]] webpage for this product.
*** Software
-~bkgpslog~ : The bash script that performs the location data
-collection and processing. Is an executable file contained within this
-repository at ~exec/bkgpslog~. It should be copied to
-~$HOME/.local/bin~.
+~bklog~ : A bash script that saves its stdin stream to a tar file. The
+file may be compressed by ~gzip~ and encrypted by ~age~. It is an
+executable file contained within this repository at ~exec/bklog~. It
+should be copied to ~$HOME/.local/bin~.
+
+~bkgpslog~ : A legacy bash script similar to ~bklog~ but narrower in
+scope in that it only records output from ~gpspipe~.
~gpsd~ : A background daemon app capable of interfacing with the
Ozzmaker BerryGPS-IMU's GPS submodule. Installed and initialized by
~apt~.
~gpsbabel~ : A command line app that converts GPS data from one format
-into another. ~bkgpslog~ uses it to convert NMEA data into GPX and
+into another. ~bklog~ may be used to convert NMEA data into GPX and
KML. Installed via ~apt~.
~gzip~ : A simple command line app that compresses stdin into a
should be copied to ~$HOME/.local/bin~.
**** Narrative
-~bkgpslog~ populates a 60-second buffer with NMEA data from ~gpsd~ via
-~gpspipe~. This buffer is used by ~gpsbabel~ to produce GPX and KML
-versions of the buffer. All 3 buffers are then comprssed with ~gzip~,
-encrypted with ~age~, and then written to disk.
+~bklog~ may be used to log location data by receiving stdout produced
+by ~gpspipe~. ~bklog~ contains options that allow file writes to be
+performed at adjustable time intervals (default: 300 seconds),
+compressed (with ~gzip~), and encrypted (with ~age~). Files are
+written in the form of appendages to a ~tar~ archive saved to a
+specified location. The NMEA data produced by ~gpspipe~ may be
+processed via a ~gpsbabel~ command string specified as an option to
+~bklog~, assuming ~gpsbabel~ is installed.
*** Output
+
+Several output file formats have been tested with ~bklog~.
+
**** File Formats
***** NMEA
-See the [[https://en.wikipedia.org/wiki/NMEA_0183][Wikipedia page]] for this.
+~NMEA~ is an acronym for National marine Electronics Association. The
+NMEA format described in this document follows the NMEA 0183
+standard. It is a newline-delimited streaming text format that encodes
+global positioning system (GPS) data such as WGS84 location, time and
+date information, satellite count, accuracy, and other
+information. Each line is an "NMEA sentence". Descriptions of various
+NMEA sentences can be found on [[http://aprs.gids.nl/nmea/][this]] webpage.
+
+See the [[https://en.wikipedia.org/wiki/NMEA_0183][Wikipedia page for NMEA 0183]] for this. This file format is the
+default output of the ~gpspipe -r~ command.
***** GPX
-See the [[https://en.wikipedia.org/wiki/GPS_Exchange_Format][Wikipedia page]] for this. [[http://wiki.gis.com/wiki/index.php/WGS84][WGS84]] is the datum used.
+See the [[https://en.wikipedia.org/wiki/GPS_Exchange_Format][Wikipedia page]] for this. [[http://wiki.gis.com/wiki/index.php/WGS84][WGS84]] is the datum used. An NMEA file
+may be converted to this format using ~gpsbabel~.
***** KML
-See the [[https://en.wikipedia.org/wiki/Keyhole_Markup_Language][Wikipedia page]] for this. [[http://wiki.gis.com/wiki/index.php/WGS84][WGS84]] is the datum used.
+See the [[https://en.wikipedia.org/wiki/Keyhole_Markup_Language][Wikipedia page]] for this. [[http://wiki.gis.com/wiki/index.php/WGS84][WGS84]] is the datum used. An NMEA file
+may be converted to this format using ~gpsbabel~.
+
**** Encryption Method
Files produced by the bkgpslog script are encrypted against a set of
public keys using [[https://github.com/FiloSottile/age][~age~]], a simple command line encryption tool
Help information for ~age~ is available by running ~$ age --help~.
***** Encryption Commands
-Files may be encrypted to several recipients using a command similar to:
+****** Encryption through ~age~
+In order to illustrate how ~bklog~ encrypts files, below is an example
+command illustrating how ~age~ may be used to encrypt a file.
+
#+BEGIN_EXAMPLE
-timeout "60s" gpspipe -r | gpsbabel -i nmea -f - -o gpx -F | age \
+$ echo "asdf" | age -r \
+age1kza7pfshy7xwygf9349zgmk7x53mquvedgw9r98qwyyqhssh830qqjzlsw \
+> "$HOME/secret_file"
+#+END_EXAMPLE
+
+The resulting ~secret-file~ is a binary blob with a plaintext header
+indicating how the blob was encrypted (which version of age was used,
+which public key was used).
+
+****** Encryption through ~bklog~
+~bklog~ may instructed to encrypt files via the ~-e~ and ~-r [pubkey
+string]~ options. An example is shown below:
+
+#+BEGIN_EXAMPLE
+$ gpspipe -r | bklog -e \
-r age1kza7pfshy7xwygf9349zgmk7x53mquvedgw9r98qwyyqhssh830qqjzlsw \
-r age1ce3pvzrqfcn2pc6zqzglc8ac8yjk3fzukpy08cesqjjwns53xywqmaq7xw \
-r age1pu5usxm743sx7rf22985xv2f4s0luzv6r6yx4fa7p8c2zyvp9fvqus2xr5 \
-> location.gpx.age
+-o "$HOME/Location"
#+END_EXAMPLE
+~bklog~ may be instructed via the ~-e~ and ~-R~ options to watch a
+directory in order to locate public key strings in its files. ~bklog~
+reads the first line of each file and interprets it as a public key
+string.
+
In this example, the strings beginning with ~age1...~ are
-bech32-formatted public key strings.
+bech32-formatted public key strings. Please see the [[*Key Generation][Key Generation]]
+section for an explanation.
+
+Since ~age~ also accepts ~ssh~ public key strings, these may also be
+used if they are of the following form (no comment).
+: ssh-rsa AAAAB3NzaC1yc2EAAAADAQABA…AACAQDLnJbPs7CjwPT+OxXd
***** Decryption Commands
Files may be decrypted using a command similar to:
#+END_EXAMPLE
The version of ~age~ used to perform the encryption
+
** Operating Procedures
*** Initial Startup
See OEM (Ozzmaker) [[https://ozzmaker.com/berrygps-berrygps-imu-quick-start-guide/][quickstart guide for the BerryGPS-IMU]].
possible.
**** Software Setup
-
***** Install Executables
Install Raspbian 10 Buster onto an SD card image. See the Raspberry Pi
Place ~age~ binary (the one compiled for ARM CPU architecture for
Linux) in ~$HOME/.local/bin~.
-***** Automatic Start Configuration
+***** Disable Swap File
+Since standard Raspbian 10 (Buster) install involves copying
+unencrypted file system image to SD card which is mounted by the
+Raspberry Pi, system memory may be written to disk in the form of a
+Swap file as described [[https://ideaheap.com/2013/07/stopping-sd-card-corruption-on-a-raspberry-pi/][here]]. In order to reduce the chance that
+location log data is ever written to disk, swap file functionality
+must be disabled[fn:ideaheap_20130731_disableswap].
+
+Raspbian 10 uses dphys-swapfile to manage a swap file. It may be
+disabled persistently[fn:rpf_20190702_disableswappersist] by running
+the following command:
-Edit the user cron job list with ~$ crontab -e~ to add the following
-lines:
+: sudo systemctl disable dphys-swapfile.service
+
+To view the status of the swap file in Raspbian 10, run ~free -m~:
#+BEGIN_EXAMPLE
-0 * * * * /bin/bash ~/bkgpslog --output ~/dir
+pi@ninfacyzga-01:~$ free -m
+ total used free shared buff/cache available
+Mem: 432 86 36 21 309 268
+Swap: 99 0 99
+#+END_EXAMPLE
+
+After disabling the swap file and rebooting:
-@reboot /bin/bash ~/bkgpslog --output ~/dir
+#+BEGIN_EXAMPLE
+pi@ninfacyzga-01:~$ free -m
+ total used free shared buff/cache available
+Mem: 432 89 214 3 128 289
+Swap: 0 0 0
#+END_EXAMPLE
-The first line will run ~bkgpslog~ at the start of every hour and save
-output files to the ~dir~ directory in your home folder.
+[fn:ideaheap_20130731_disableswap] Explanation:
+https://ideaheap.com/2013/07/stopping-sd-card-corruption-on-a-raspberry-pi/
-The second line will run ~bkgpslog~ when the system starts up.
+[fn:rpf_20190702_disableswappersist] Persistant disabling of swap in
+Raspbian 10 Buster:
+https://www.raspberrypi.org/forums/viewtopic.php?p=1490692&sid=5c596a124b7805d6b10dab8d3d7caf16#p1490692
-~/bin/bash~ tells ~cron~ to run ~bkgpslog~ with Bash.
+***** Automatic Start Configuration
-If encryption and compression are required, then the appropriate
-options must be added. The lines that must be added via ~$ crontab -e~
-may resemble:
+It is recommended to create a daily ~cron~ job that executes a bash
+script that starts ~bklog~ jobs to record location along with other
+types of data recording. An example of such a script is below:
#+BEGIN_EXAMPLE
-0 * * * * /bin/bash ~/bkgpslog -c -e -r age1z2...qkv6p -o ~/dir
-
-@reboot /bin/bash ~/bkgpslog -c -e -r age1z2...qkv6p -o ~/dir
+#!/bin/bash
+
+# Log location
+gpspipe -r | /bin/bash "$HOME/.local/bin/bklog" -c -e -z "UTC" -t "/dev/shm" \
+ -r age1kza7pfshy7xwygf9349zgmk7x53mquvedgw9r98qwyyqhssh830qqjzlsw \
+ -r age1ce3pvzrqfcn2pc6zqzglc8ac8yjk3fzukpy08cesqjjwns53xywqmaq7xw \
+ -R "$HOME/.config/bklog/recipients" -w ".nmea" -b "300" -B "day" \
+ -o "$HOME/Sync/Evanescent_Location" -l "location" \
+ -p "gpsbabel -i nmea -f - -o gpx -F - " ".gpx" \
+ -p "gpsbabel -i nmea -f - -o kml -F - " ".kml" &
+# Log pressure
+python ~/.local/bin/bmp388.py | /bin/bash "$HOME/git-OC/ninfacyzga-01/exec/bklog" \
+ -c -e -z "UTC" -t "/dev/shm" \
+ -r age1kza7pfshy7xwygf9349zgmk7x53mquvedgw9r98qwyyqhssh830qqjzlsw \
+ -r age1ce3pvzrqfcn2pc6zqzglc8ac8yjk3fzukpy08cesqjjwns53xywqmaq7xw \
+ -R "$HOME/.config/bklog/recipients" -w ".txt" -b "300" -B "day" \
+ -o "$HOME/Sync/Evanescent_Location" -l "pressure" &
#+END_EXAMPLE
-The ~age1z2...qkv6p~ is an ~age~ public key string. Please see the
-[[*Key Generation][Key Generation]] section for an explanation.
+This script, if it were saved at
+~"$HOME/.local/bin/cron/dailylog.sh"~ would then be added as a
+line in the ~crontab~ file as shown below:
-The options are:
+#+BEGIN_EXAMPLE
+$ crontab -e
+0 0 * * * /bin/bash ~/.local/bin/cron/dailylog.sh
+@reboot /bin/bash ~/.local/bin/cron/dailylog.sh
+#+END_EXAMPLE
-: -c : tells bkgpslog to compress output
-: -e : tells bkgpslog log to encrypt output
-: -r : tells bkgpslog to interpret the next argument as a pubkey string
-: -o : tells bkgpslog to write output files to the directory represented
+In the example script, the options are:
+
+: -c : tells bklog to compress output
+: -e : tells bklog log to encrypt output
+: -r : tells bklog to interpret the next argument as a pubkey string
+: -R : tells bklog to interpret the next argument as a directory
+: where public keys may be found (first line of each file is
+: read).
+: -o : tells bklog to write output files to the directory represented
+: -t : tells bklog to interpret the next argument as a directory
+: for storing temporary files
: by the next argument
+: -p : tells bklog a command string through which output is piped
+: before being compressed and encrypted. Also expected is a
+: file extension to be appended before the compression and
+: encryption file extensions.
+: -w : tells bklog to save the unprocessed stdin with a specified
+: file extension (instead of the default '.stdin').
+: -b : tells bklog how long each buffer round (time between file
+: writes) lasts in seconds.
+: -B : specifies the time-to-live for the bklog script. A valid value may
+: one of the time elements such as "day" or "hour".
+: -l : specfies a custom string to be used in output file names to
+: help differentiate tar files produced via bklog from different
+: sources of data.
+: -z : specifies a time zone to be used to determine the script time-to-live.
+: By default, bklog uses whatever time is specified by the TZ
+: environment variable.
***** Log Transfer Configuration
Log files may be shared to other machines via ~syncthing~. See [[https://docs.syncthing.net/][this]]
#+BEGIN_EXAMPLE
$ umask # Gets current umask
0022 # Note: This is the default umask for Raspbian 10
-$ umask 066 # Sets umask so key.txt will have no permissions except for owner (you)
+$ umask 066 # So key.txt will have no perms except for owner (you)
$ umask # Confirm umask set to 066
0066
$ age-keygen > key.txt
Take extra precuation if lead solder was used in assembling the
electronics. Consumer electronics in early 21st century should use
lead-free solder.
-
projects / EVA-2020-02.git / blobdiff