Logstash is a part of the ELK (Elasticsearch — Kibana — Logstash) stack, from Elastic. Its a centralized log drain for all your logs from various sources.
I couldn’t find any nice tutorials on setting up Logstash on a DigitalOcean droplet, and sending logs to it from a Heroku Rails App, over TCP with SSL. Certificate creation also seems poorly documented online.
So let’s get to it.
Create A new DigitalOcean droplet with Ubuntu 18.04, and at least 2gb of ram, as logstash eats 1 gb.
Use this Github Repo to setup basic packages.
Follow DigitalOcean’s fantastic guide on setting…
Adjusting stock prices for dividends and splits is a common problem.
The following links illustrate methodologies used by various data providers.
The idea is to send a .prn file generated using these instructions to the printer directly. Do this by hooking the printer into CUPS,and use the CUPS -raw option to send your file to the printer, via command line, like this:
lpr -P TSC_TE244 -o raw ./barcodes.prn
If you don’t use the raw option, the barcode printer will try to print the contents of the file directly as text. We don’t want that. We want it to interpret the file and generate the barcode as per that file.
The paper illustrates a method to prepare hemolyzed controls using EDTA samples from routine laboratory patients.
Self-made controls (n = 2) were prepared using fresh EDTA blood. EDTA blood, 120 g/L, artificially hemolyzed by making a 1:5 dilution with distilled water then vortex mixed at room temperature, then further diluted to the desired concentrations with pooled human plasma without pathological serum indices (a 1:20 dilution, resulting in 1.2 g/L High L1 control and a 1:50 dilution, resulting in a 0.48 g/L Low…
Elasticsearch is construed primarily as a search engine and log consumption system.
Most people advocate using something like MySQL/PostgreSQL/Mongo as the primary database and Es as an indexing backend.
ES can however, be used as a database, obviating the need for a primary database, altogether.
The motivation behind this is as follows: