feat: Allows saving of HTTP events into PostgreSQL

[andyquinterom]

This feature will allow us track the number of requests, response times and other data for plumber APIs and Shiny Applications.

• Closes Add a way to save http events into postgresql #151

The new feature

HTTP Telemetry

faucet now offers the option of saving HTTP events to a PostgreSQL database.
This can be very helpful for tracking latency, total API calls and other
important information.

In order to use this feature you will need a PostgreSQL database with a table
called faucet_http_events. You can create the table using this table with
the following SQL query:

CREATE TABLE faucet_http_events (
    request_uuid UUID,
    namespace TEXT,
    version TEXT,
    target TEXT,
    worker_route TEXT,
    worker_id INT,
    ip_addr INET,
    method TEXT,
    path TEXT,
    query_params TEXT,
    http_version TEXT,
    status SMALLINT,
    user_agent TEXT,
    elapsed BIGINT,
    time TIMESTAMPTZ
);

Connection Strings

In order to connect to the database you will need to pass the
FAUCET_TELEMETRY_POSTGRES_STRING environment variable or the
--pg-con-string CLI argument.

This should include either a connection string or a URL with the postgres://
protocol.

Example connection strings

FAUCET_TELEMETRY_POSTGRES_STRING="host=localhost user=postgres connect_timeout=10 keepalives=0"
FAUCET_TELEMETRY_POSTGRES_STRING="host=/var/lib/postgresql,localhost port=1234 user=postgres password='password with spaces'"
FAUCET_TELEMETRY_POSTGRES_STRING="postgresql://user@localhost"
FAUCET_TELEMETRY_POSTGRES_STRING="postgresql://user:[email protected]/mydb?connect_timeout=10"

Telemetry Namespaces

It is likely you want to track different services on the same database. You
can control the column namespace using the environment variable
FAUCET_TELEMETRY_NAMESPACE or cli argument --telemetry-namespace. By
default, this value is "faucet"

[andyquinterom]

Video showcase: https://youtu.be/VpmVc6hI-F4

[andyquinterom]

Example values in the table:

   namespace    |  target   | worker_route | worker_id |  ip_addr  | method |     path      |   query_params    | version  | status |       user_agent        | elapsed |             time
----------------+-----------+--------------+-----------+-----------+--------+---------------+-------------------+----------+--------+-------------------------+---------+-------------------------------
 simple-plumber | Worker::1 |              |         1 | 127.0.0.1 | GET    | /__docs__/    |                   | HTTP/1.1 |    200 | Mozilla/5.0 (X11; Li... |      49 | 2024-10-27 01:07:30.827733+00
 simple-plumber | Worker::1 |              |         1 | 127.0.0.1 | GET    | /openapi.json |                   | HTTP/1.1 |    200 | Mozilla/5.0 (X11; Li... |      93 | 2024-10-27 01:07:31.024664+00
 simple-plumber | Worker::1 |              |         1 | 127.0.0.1 | GET    | /echo         | msg=Hello%20World | HTTP/1.1 |    200 | Mozilla/5.0 (X11; Li... |       4 | 2024-10-27 01:07:38.186839+00
 simple-plumber | Worker::1 |              |         1 | 127.0.0.1 | GET    | /plot         | spec=setosa       | HTTP/1.1 |    200 | Mozilla/5.0 (X11; Li... |      45 | 2024-10-27 01:07:47.522051+00

[FvD]

This is great. I went 🤯 with the telemetry demo, and I am at least as impressed by how you implemented it. Please change the draft status at your earliest convenience so that I can merge the PR.