{"id":14444,"date":"2020-07-21T08:29:45","date_gmt":"2020-07-21T06:29:45","guid":{"rendered":"https:\/\/www.dbi-services.com\/blog\/java-and-influxdb-http-api\/"},"modified":"2020-07-21T08:29:45","modified_gmt":"2020-07-21T06:29:45","slug":"java-and-influxdb-http-api","status":"publish","type":"post","link":"https:\/\/www.dbi-services.com\/blog\/java-and-influxdb-http-api\/","title":{"rendered":"Java and InfluxDB http api"},"content":{"rendered":"

InfluxDB<\/h1>\n

InfluxDB is a powerfull open source time series database (TSDB) developped by InfluxData. It’s a database optimized for time-stamped or time series data. Time series data are simply measurements or events that are tracked.
\nIt is particully interresting for metric tracking like server cpu, ram, application performances and so on.<\/p>\n

It is similar to SQL databases but different in many ways. The key here is the time. The database engine is optimized for high ingest and data compression. It is wrtten in Go and compiles in one single binary without any dependencies.
\nWe can use it through a cli but the most interesting part is it’s HTTP API which will allow us to perform actions on the measurements without any third party api.
\nIt can be installed on a single server or in the cloud. It is highly compatible with Telegraf, a time series data collector, but we will discuss it on another blog.<\/p>\n

Installation<\/h1>\n

I did the installation on a CentOS but it can be installed on other linux distributions, OS X and windows. You can download the rpm\/zip\/tar on the download page<\/a> or you can install it directly like following:<\/p>\n

Add the repo:<\/p>\n

cat <<EOF | sudo tee \/etc\/yum.repos.d\/influxdb.repo\n[influxdb]\nname = InfluxDB Repository - RHEL $releasever\nbaseurl = https:\/\/repos.influxdata.com\/rhel\/$releasever\/$basearch\/stable\nenabled = 1\ngpgcheck = 1\ngpgkey = https:\/\/repos.influxdata.com\/influxdb.key\nEOF<\/pre>\n
Ensure the cache is up to date:<\/p>\n
sudo yum makecache fast<\/pre>\n
Install the database, we install curl in order to test the HTTP API:<\/p>\n
sudo yum -y install influxdb vim curl<\/pre>\n
We enable the HTTP API:<\/p>\n
sudo vim \/etc\/influxdb\/influxdb.conf\n[http]\n  enabled = true\n  bind-address = \":8086\"\n  auth-enabled = true\n  log-enabled = true\n  write-tracing = false\n  pprof-enabled = true\n  pprof-auth-enabled = true\n  debug-pprof-enabled = false\n  ping-auth-enabled = true<\/pre>\n
We start and enable the service:<\/p>\n
sudo systemctl start influxdb && sudo systemctl enable influxdb<\/pre>\n
We need to open the port used by InfluxDB:<\/p>\n
sudo firewall-cmd --add-port=8086\/tcp --permanent\nsudo firewall-cmd --reload<\/pre>\n
Now we create an admin account:<\/p>\n
curl -XPOST \"http:\/\/localhost:8086\/query\" --data-urlencode \"q=CREATE USER username WITH PASSWORD 'password' WITH ALL PRIVILEGES\"<\/pre>\n
If the query executed correctly you shouldn’t have any response.<\/p>\n
You can now test your connection with the cli:<\/p>\n
influx -username 'username' -password 'password'<\/pre>\n
You can list the databases with:<\/p>\n
SHOW DATABASES<\/pre>\n
To create a database do the following:<\/p>\n
CREATE DATABASE mymetrics<\/pre>\n
And to navigate to your created DB:<\/p>\n
USE mymetrics<\/pre>\n
Once you’ll have some entries you will be able to list them like:<\/p>\n
SHOW MEASUREMENTS<\/pre>\n
And then you can execute basic SQL like queries (only when you have measurements):<\/p>\n
SELECT * FROM metric_cpu_load<\/pre>\n
 <\/p>\n
Measurements via Java<\/h1>\n
Now that we have our DB setup and a user to connect, we will generate measurements with Java. But you can do it with any HTTP request compatible languages. It exists a Java api to discuss with the database directly (here<\/a>) but I wanted to do it through the HTTP API.<\/p>\n
You will need httpclient.jar and httpcore.jar from Apache Commons to use the latest http api. The version I used was:<\/p>\n