POSM Imagery API

This is the POSM Imagery API. It does a few things:

• ingests GeoTIFFs (and probably other GDAL-supported formats, though it currently looks for .tif and .tiff extensions) using HTTP multipart uploads and via the tus.io protocol for resumable uploads.
• creates overviews and associated metadata to facilitate tiling
• tiles imagery on-demand
• creates MBTiles archives for individual images (and should do the same for imagery sets)

Running

First, start redis-server so that Docker containers can access it (so that Celery can use it as a broker and result backend and so that Flask-Tus can track uploads):

redis-server --bind 0.0.0.0

This runs gunicorn under the hood (using the default Docker ENTRYPOINT).

# get the host IP on OS X (wired, then wireless)
ip=$(ipconfig getifaddr en0 || ipconfig getifaddr en1)
docker run \
  -it \
  --rm \
  -e WEB_CONCURRENCY=8 \
  -e REDIS_URL="redis://${ip}/" \
  -v $(pwd)/imagery:/app/imagery \
  -v $(pwd)/uploads:/app/uploads \
  -p 8000:8000 \
  imagery-api

This overrides the default ENTRYPOINT and starts the Celery daemon to run workers instead. Note that the imagery and uploads volumes are shared between containers.

# get the host IP on OS X (wired, then wireless)
ip=$(ipconfig getifaddr en0 || ipconfig getifaddr en1)
docker run \
  -it \
  --rm \
  -e REDIS_URL="redis://${ip}/" \
  -v $(pwd)/imagery:/app/imagery \
  -v $(pwd)/uploads:/app/uploads \
  --entrypoint celery \
  imagery-api \
  worker \
  -A app.celery \
  --loglevel=info

Developing

You can either run a development copy with docker-compose:

docker-compose up

...or you can develop against a local copy. To set up, create a virtualenv, install the dependencies, and start up the API server and Celery workers. You'll also need a local Redis server.

Create a virtualenv and install dependencies:

virtualenv venv
source venv/bin/activate
pip install -U numpy # install this first so rasterio doesn't complain
pip install -Ur requirements.txt
npm install

Start the API server:

source venv/bin/activate
python app.py

Start the Celery workers:

source venv/bin/activate
venv/bin/celery worker -A app.celery --loglevel=info

To start Redis:

redis-server

API Endpoints

To see an up-to-date list of API endpoints (and supported methods), run python manage.py list_routes.

• GET /imagery - List available imagery.
• GET /imagery/<id> - Get metadata for an image.
• GET /imagery/<id>/<z>/<x>/<y>[@2x].png - Tile endpoint for an image.
• GET /imagery/<id>/ingest/status - Check on the ingestion status for an image.
• GET /imagery/<id>/mbtiles - Download the MBTiles archive for an image (if available).
• POST /imagery/<id>/mbtiles - Request creation of an MBTiles archive.
• GET /imagery/<id>/mbtiles/status - Check on the status of MBTiles creation.
• PUT /imagery/upload - Upload imagery. Requires the image to be the file value of a multipart/form-data payload. E.g., curl -X PUT -F "file=@image.tif" http://localhost:8000/imagery/upload
• POST /imagery/upload - tus.io upload endpoint.

Environment Variables

• APPLICATION_ROOT - Optional application prefix. Defaults to ``.
• IMAGERY_PATH - Where to store imagery on the filesystem. Must be accessible by both the API server and Celery workers. Defaults to imagery (relative to the current working directory).
• UPLOADED_IMAGERY_DEST - Where to (temporarily) store uploaded imagery. Must be accessible by both the API server and Celery workers. Defaults to uploads/ (relative to the current working directory).
• MIN_ZOOM - Minimum zoom served up by the tile server. Defaults to 0.
• MAX_ZOOM - Maximum zoom served up by the tile server. Defaults to 22.
• CELERY_BROKER_URL - Celery broker URL. Defaults to the value of REDIS_URL.
• CELERY_DEFAULT_QUEUE - Default queue name. Defaults to posm-imagery-api.
• CELERY_RESULT_BACKEND - Celery result backend URL. Defaults to the value of REDIS_URL.
• REDIS_URL - Flask-Tus backend. Defaults to redis:// (localhost, default port, default database).
• SERVER_NAME - Local server name, for use when generating MBTiles. Defaults to localhost:8000.
• USE_X_SENDFILE - Whether Flask should use X-Sendfile to defer file serving to a proxying web server (this requires that the web server and API server are running on the same "server", so Docker won't work). Defaults to False.
• MBTILES_TIMEOUT - How long to wait before timing out MBTiles archive creation tasks. Defaults to 3600s (1 hour).
• TASK_TIMEOUT - How long to wait before timing out tasks. Defaults to 900s (15 minutes).