This is a reimplementation of N2T using python.
N2T is an identifier scheme resolver. Its role is to redirect clients to the registered handler for an identifier scheme. The handler is expected to continue interaction with the client for identifier resolution.
On server instance:
Given the YUM repository description file unit.repo
:
[unit]
name=unit repo
baseurl=https://packages.nginx.org/unit/amzn/2023/$basearch/
gpgcheck=0
enabled=1
Add the repository and install Nginx unit
:
sudo yum update
sudo yum install yum-utils
sudo /usr/bin/yum-config-manager --add-repo unit.repo
sudo yum update
sudo yum install unit
sudo yum install unit-devel unit-jsc17 unit-python311 unit-wasm
sudo cdlsysctl start unit
Note: The service is installed as disabled and it needs to be enabled unit, but
cdlsysctl
doesn't allow that so needs to be done by an administrator, e.g.:
sudo systemctl enable unit
Is the service running?
sudo cdlsysctl status unit
● unit.service - NGINX Unit
Loaded: loaded (/usr/lib/systemd/system/unit.service; disabled; preset: disabled)
Active: active (running) since Wed 2024-02-28 04:32:23 PST; 4s ago
Main PID: 1893665 (unitd)
Tasks: 3 (limit: 1055)
Memory: 5.7M
CPU: 16ms
CGroup: /system.slice/unit.service
├─1893665 "unit: main v1.32.0 [/usr/sbin/unitd --log /var/log/unit/unit.log --pid /var/run/unit/unit.pid --no-daemon]"
├─1893667 "unit: controller"
└─1893668 "unit: router"
To enable access to unit
by the ezid
user, it is necessary to override the
default systemd startup for unit. This is done with an override.conf
file in
/etc/systemd/system/unit.service.d
:
[Service]
Environment="UNITD_OPTIONS=--log /var/log/unit/unit.log --pid /var/run/unit/unit.pid --user ezid --group ezid"
Group=ezid
ExecStartPost=/usr/bin/sh -c 'sleep 3; chmod 660 /var/run/unit/control.sock; chmod 640 /var/log/unit/*.log'
Show the current unit
configuration:
$ curl -X GET --unix-socket /var/run/unit/control.sock http://localhost/config/
{
"listeners": {},
"routes": [],
"applications": {}
}
Setup python and application. Installing the application is done by cloning from
the GitHub repository. From the application home (i.e. /ezid
on UC3 systems):
git clone https://github.com/CDLUC3/n2t.git
cd n2t
python3.11 -m venv venv
source venv/bin/.activate
python --version
Python 3.11.6
python -m pip install -U pip
python -m pip install -e .
Run the n2t
cli to verify the application is installed:
$ n2t
Usage: n2t [OPTIONS] COMMAND [ARGS]...
Management commands for N2T.
This script is used for initializing the JSON representation of scheme
records from the original YAML and creating or updating the sqlite store
used by the resolver application.
Options:
-c, --config FILE
--help Show this message and exit.
Commands:
info Print application version and basic status.
loaddb Load or update the scheme database.
yaml2json Generate or update JSON record from YAML source.
Before operation, the N2T application scheme database must be initialized. This process creates an sqlite database containing the scheme records to support resolution. The scheme records are loaded from the JSON sources, and the database will need to be updated when the JSON sources are modified.
The N2T application is configured using a .env
file. The available properties
include:
Key | Default | Description |
---|---|---|
N2T_HOST |
localhost |
Address to listen when running in dev mode. |
N2T_PORT |
8000 |
Port to listen on when running in dev mode. |
N2T_PROTOCOL |
http |
Protocol to listen on (http or https ). |
N2T_DB_CONNECTION_STRING * |
sqlite:///BASE/data/n2t/sqlite |
SQLAlchemy connection string (sqlite preferred). |
N2T_JSON_DIR * |
BASE/schemes |
Folder where the scheme definitions are located. |
N2T_STATIC_DIR * |
BASE/static |
Folder from where static content is served (styles, images, scripts). |
N2T_TEMPLATE_DIR * |
BASE/templates |
Folder from which templated content is served. |
N2T_ENVIRONMENT |
development |
A human readable label for the service (development, staging, production) |
*: Default folder locations are relative to the n2t
folder in the cloned repository.
A typical configuration file for a staging environment will be:
N2T_DB_CONNECTION_STRING="sqlite:///data/n2t.sqlite"
N2T_JSON_DIR="schemes"
N2T_ENVIRONMENT="staging"
Those settings indicate the name of the environment "staging", that the JSON
scheme definitions are in the folder schemes
and the application
database is data/n2t.sqlite
. The folders are relative to the location where
the n2t
command is run. These properties may also use absolute paths, for
example:
N2T_DB_CONNECTION_STRING="sqlite:////ezid/var/n2t.sqlite"
N2T_JSON_DIR="/ezid/n2t/schemes"
Any of the settings are overridden by an equivalent named environment variable if set.
If the schemes
folder is not present it needs to be created from the
legacy N2T prefixes file:
wget "https://n2t.net/e/n2t_full_prefixes.yaml"
n2t yaml2json
The application database may be created and populated when the JSON scheme records are available:
cd /ezid/n2t
mkdir -p data
n2t loaddb
To verify setup, use the info
command. The output should be something like:
$ n2t info
{
"version": "0.5.0",
"environment": "development",
"status": "initialized",
"description": "n2t_full_prefixes",
"created": "2024-03-06T16:01:43.245204",
"schemes": {
"total": 2774,
"valid": 1596
}
}