Markup to Pdf/HTML

2019-07-27T20:39:13+01:00

---

Contents

• Introduction
• Using VSCode extension.
• Using pandoc/latex/Tex
  • Run following command to generate PDF
  • Run following command to generate HTML:

---

Introduction

This documents shows the various ways to generate PDF and self contained HTML files.

Using VSCode extension.

Install VSCode and install extension Markdown PDF. Write a new markup page in VSCode. When done, right click on the editor and you will see the options to export to PDF and HTML.

• pros
  1. Easy installation and generation of PDF
  2. Line wraps in code blocks.
• cons
  1. Not very eye pleasing.
  2. Headings like h1, h2 are not consistent in rendered pdf.

Using pandoc/latex/Tex

Install pandoc, macTex and TeX Live. Create a workspace are and clone following two git repos in that workspace area.

mkdir $HOME/panDocs
cd $HOME/panDocs
git clone https://github.com/Wandmalfarbe/pandoc-latex-template.git
git clone https://github.com/tajmone/pandoc-goodies.git

• pandoc-goodies is to generate html files.
• pandox-latex-template is to generate pdf files.

Create an markup file in $HOME/panDocs say input.md.

Run following command to generate PDF

PDF generation

pandoc input.md -f markdown --template pandoc-latex-template/eisvogel.tex --listings -o output.pdf --highlight-style pygments  -V lang=en-GB -V listings-disable-line-numbers=true --toc --toc-depth 6

Above command will generate an pdf file of name output.pdf

Run following command to generate HTML:

Self contained HTML

pandoc input.md -f markdown --template pandoc-goodies/templates/html5/github/GitHub.html5 --self-contained --toc --toc-depth=6 -o output.html

Above command will generate a self contained HTML file of name output.html

Minimal Working Tmux Config

2020-03-15T20:33:04Z

---

Contents

• Minimal working tmux config
• Launch tmux

---

Minimal working tmux config

Populate $HOME/.tmux.conf with following contents

set -g default-terminal "screen-256color"
set -g history-limit 99999
# setw -g status-utf8 on

# status line background colour will be the colour of terminal in background
set -g status-bg default
setw -g display-time 5000

####################################################################################################
#      settings for TMUX widnows status decorations                                                #
####################################################################################################
# status format for both last-active-window and all the windows before last-active
# commas are escaped using # char in below statement. i.e #, => escapes comma. Below 5 lines are actually one line broke up into 5
setw -g window-status-format "#{\
?window_last_flag,\
#[bold #, bg=colour226 #, fg=colour232] #I.#P #W ,\
#[bold #, bg=colour124 #, fg=colour232] #I.#P #W \
}"

# status format for current active window
setw -g window-status-current-format "#[bold #, bg=colour77 #, fg=colour232] #I.#P#F #W "
setw -g window-status-separator "   "

####################################################################################################
#      settings for TMUX pane status decorations                                                   #
####################################################################################################
setw -g pane-border-status top

# we do not need bg colour here as we want the bg colour to be the colour of the terminal, therefore bg is set to default. We may even omit bg here.
# set the colouring of border for current active pane
setw -g pane-active-border-style bg=default,fg=colour81

# we cannot have space after the comma here.
# set the colouring of border for non-current pane
setw -g pane-border-style bg=default,fg=colour180

# commas are escaped using # char in below statement. i.e #, => escapes , . Below 5 lines are actually one line broke up into 5
# two different colour schemes for current and all non-current panes TEXT
setw -g pane-border-format "#{\
?pane_active,\
#[bold #, bg=colour81 #, fg=colour16]  ~>> #I.#P   #T <<~  ,\
#[bg=colour180 #, fg=colour16] #I.#P #T \
}"

####################################################################################################
#      Other settings                                                                              #
####################################################################################################
set -g allow-rename off
set -g mode-keys vi
set-option -g mouse on

Launch tmux

tmux -u

Note: -u is specified for terminals where locale is not set to UTF-8 Note To change the title of pane run this command ctrl-b :select-pane -T MyTitle

Very simple template substitutions using Python and Perl

Very Simple Template Substitutions Using Python Perl

2020-03-15T20:50:05Z

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Contents

• Introduction
• Using Python
• Using Shell and Perl

---

Introduction

It is quite common to treat text files as templates which contains place holders that will be replaced by some real values. Python jinja or Ruby erb template engines are there to resolve for these kind of issues. They are quite feature rich. Following is a very simple Template substitution program in Python and Perl that does similar kind of job. Its very basic but works for simple scenarios.

Using Python

Consider following text file test_file.txt with place holders in it.

This is a %TEST1% . Another %TEST1%  %TEST1%
Now this is a %TEST2%.

Following is the file var.py containing values of above place holder.

TEST1="test_string1"
TEST2="test_string2"

Following is the python program that will replace above values in test_file.txt from var.py file.

#! /usr/bin/env python

import re
import fileinput
import sys
from var import *

def print_data_vars(matchObj):
    return globals()[matchObj.group(1)]

for line in fileinput.input('test_file', inplace=True):
    line = re.sub(r'%(.+?)%', print_data_vars, line)
    sys.stdout.write(line)

when above program is run , it will replace placeholders with values in existing test_file.txt file.

Using Shell and Perl

Assuming var.py and test_file.txt contents are same as above, same effect can also be achieved using shell and perl combination as follows.

#! /usr/bin/env bash
set -a
source ./var.py
set +a
perl -i -wpl -e 's!%(.+?)%!$ENV{$1}!g' test_file

Saltstack: Call runner from minion (jinja conditionals)

2020-03-15T21:05:23Z

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Contents

• Introduction
• Pre-Requisites
• Preparation
• Execution

---

Introduction

Sometimes a minion may need to execute something which is central to whole system but based on some condition. e.g. Minion may need to update an external common Database whose write access is given only to master. Therefore minion may need to ask salt-master to execute on its behalf. This can be done by

• Minion calling runner on salt-master
• runner executing a custom execution module that provides access to DB

As a custom execution module needs to be executed on salt-master, therefore salt-minion also needs to be installed on salt-master. And configure salt-minion to accept the commands from salt-master. This will be configured as a normal salt-minion. Nothing special needs to be done. Thus salt-master machine would be running both salt-master and salt-minion.

Once above DB operation is done, something else might need to be done. This can be achieved by using jinja in state files.

Pre-Requisites

• salt-master installed and configured on a machine. I used fedora-24 VM.
• salt-minion installed and configured to accept command from salt-master.

Preparation

/etc/salt/master file used.

log_level: debug

peer_run:
  .*:
    - .*

fileserver_backend:
  - roots

file_roots:
  base:
    - /srv/salt

runner_dirs:
  - /srv/salt/_runners

/etc/salt/minion file used.

master: salt

Note: In /etc/salt/master file, log_level is set to debug. Normally this will be info. Also take a note of peer_run config. This is must. At the moment this is very open and you may like to narrow it down.

my_module.py will be our execution module.

mkdir /srv/salt/_modules
touch /srv/salt/_modules/my_module.py
mkdir /srv/salt/_runners
touch /srv/salt/_runners/my_runner.py

Contents of /srv/salt/_modules/my_module.py are as follows.

#! /usr/bin/env python

# Below virtual name can be any string.
__virtualname__ = 'my_module'

def __virtual__():
    return __virtualname__

def my_module_function(arg1, arg2):
    modified_arg1 = '%s_%s' % (arg1, 'modified')
    modified_arg2 = '%s_%s' % (arg2, 'modified')
    return True

Contents of /srv/salt/_runners/my_runner.py are as follows.

#! /usr/bin/env python
import salt.client
import salt.loader
import salt.config

def my_runner_function(arg1, arg2):
    __opts__ = salt.config.minion_config('/etc/salt/master')
    mods = salt.loader.minion_mods(__opts__)
    ret = mods['my_module.my_module_function'](arg1, arg2)
    return ret

Above runner can be called from command line as follows:

root@salt-master# salt-run my_runner.my_runner_function 'a_string' 'b_string'
True
[INFO    ] Runner completed: 20170109200157859211

Now we will ask minion to execute runner on master.

Create a state file /srv/salt/jinja_state_file_calling_runner_on_master.sls as following:

{% set some_changes = salt['publish.runner']('my_runner.my_runner_function', ['argument1', 'argument2']) %}

{% if some_changes == True %}
install tcpdump:
  pkg.installed:
    - name: tcpdump
{% else %}
install git:
  pkg.installed:
    - name: git
{% endif %}

Note1: In above state file, if the execution of execution module my_module is True then tcpdump will be installed otherwise git will be installed.

Execution

Run following command to sync all modules with all minions.

root@salt-master# salt '*' saltutil.sync_all
fedora2.vagrant.box:
    ----------
    beacons:
    engines:
    grains:
    log_handlers:
    modules:
        - modules.custom_module
        - modules.my_module
    output:
    proxymodules:
    renderers:
    returners:
    sdb:
    states:
    utils:
fedora.vagrant.box:
    ----------
    beacons:
    engines:
    grains:
    log_handlers:
    modules:
        - modules.custom_module
        - modules.my_module
    output:
    proxymodules:
    renderers:
    returners:
    sdb:
    states:
    utils:

Now execute above state file on remote minion by running following command.

root@salt-master# salt 'fedora2.vagrant.box' state.sls jinja_state_file_calling_runner_on_master
fedora2.vagrant.box:
----------
          ID: install tcpdump
    Function: pkg.installed
        Name: tcpdump
      Result: True
     Comment: Package tcpdump is already installed
     Started: 20:05:03.065341
    Duration: 420.049 ms
     Changes:

Summary for fedora2.vagrant.box
------------
Succeeded: 1
Failed:    0
------------
Total states run:     1
Total run time: 420.049 ms