Exposure Log

Exposure log is a REST web service to create and manage log messages that are associated with a particular exposure.

The service runs at _address_:8080/exposurelog and OpenAPI docs are available at _address_:8080/exposurelog/docs.

Messages are immutable, other than two fields: date_invalidated and is_valid (which is computed from date_invalidated). These fields provide a reasonable approximation of deletion and modification.

Configuration

The service is configured via the following environment variables; All are optional except the few marked "(required)":

• SITE_ID (required): Where this is deployed. Standard values include "summit" and "base".
• BUTLER_URI_1 (required): URI to an butler data repository, which is only read. Note that Exposure Log only reads the registry, so the actual data files are optional.
• BUTLER_URI_2: URI to a second, optional, data repository, which is searched after the first one.
• EXPOSURELOG_DB_USER: Exposurelog database user name: default="exposurelog".
• EXPOSURELOG_DB_PASSWORD: Exposurelog database password; default="".
• EXPOSURELOG_DB_HOST: Exposurelog database server host; default="localhost".
• EXPOSURELOG_DB_PORT: Exposurelog database server port; default="5432".
• EXPOSURELOG_DB_DATABASE: Exposurelog database name; default="exposurelog".

Developer Guide

Create (once) and activate a local conda environment:

conda create --name square python=3.10
conda env list

conda activate square

For development work, you can install dependencies into the current conda environment, and put the src directory in the PYTHONPATH using:

make init

If you change requirements (in requirements/dev.in or main.in), or if running the code gives a "package not found" error, update the generated dependencies and install the new requirements using:

make update-deps
make update

tox configuration goes in pyproject.toml (not tox.ini, as tox documentation often suggests).

To run tests (including code coverage, linting and typing):

tox

If that fails with a complaint about missing packages try rebuilding your environment:

tox -r

To lint the code, including type checking (run it twice if it reports a linting error the first time):

tox -e lint

To run the service, you will need a running Postgres server with a user named exposurelog that has permission to create tables and rows, and a database also named exposurelog. With the Postgres server running:

# Configure the service
export SITE_ID=test
export BUTLER_URI_1=.../exposurelog/tests/data/LATISS
# Also set EXPOSURELOG_DB_x environment variables as needed; see Configuration above

# Start the service.
# The default port is 8000, but the LSST standard port is 8080.
# --reload will reload the source code when you change it (don't use for production).
uvicorn exposurelog.main:app [--port n] [--reload]

# If running the service locally on port 8000, connect to it at: http://localhost:8000/exposurelog/

Postgres Guide

This is a very basic guide focused on the exposurelog service.

To start postgres manually (in case you don't routinely leave it running):

pg_ctl -D /usr/local/var/postgres start

To stop postgres manually:

pg_ctl -D /usr/local/var/postgres stop -s -m fast

To connect to the postgres server in order to create a new user or database:

psql -U postgres -d postgres

To create the exposurelog user and database:

CREATE USER exposurelog WITH CREATEDB;
CREATE DATABASE exposurelog;

To connect as user exposurelog and use the exposurelog database (e.g. to see data or schema):

psql -U exposurelog -d exposurelog

List all databases:

\l

Show the schema for the current table:

\d