adds interactivity to services.swpc.noaa.gov/images/animations. uses prefect for a backend to scrape images generate movies with ffmpeg. flask frontend at /iframe + proxy server via bare domain and API access via /api.
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import os
import re
from datetime import datetime, timedelta
from io import BytesIO
from typing import Dict, Iterator, List
import httpx
# import imageio
import numpy as np
from moviepy.editor import ImageSequenceClip
from PIL import Image
from prefect import flow, task
from prefect.tasks import task_input_hash
BASE_URL = "https://services.swpc.noaa.gov/images/animations/geospace/"
@task(
retries=3,
retry_delay_seconds=5,
cache_key_fn=task_input_hash,
cache_expiration=timedelta(minutes=2),
log_prints=True,
)
def get_file_links(url: str, ext: str | None = None) -> Iterator[str]:
response = httpx.get(url)
response.raise_for_status()
webpage_content = response.text
if ext is None:
print("Extension not supplied. Inferring (less efficient) png/jpg/jpeg")
exts = ["png", "jpg", "jpeg"]
else:
exts = [ext.lower()]
lines = webpage_content.split("\n")
for line in lines:
for ext in exts:
if ext in line: # need to parse the href link
start_pos = line.find('href="') + len('href="')
end_pos = line.find('"', start_pos)
href = line[start_pos:end_pos]
if href.endswith(f"latest.{ext}"):
print("Skipping latest")
continue
if href.endswith(ext):
if not href.startswith("http"):
href = url + href
yield href
break # Exit the inner loop to avoid duplicate yields for multiple exts
def url_tail_hash(context, parameters):
# return a constant
return parameters["url"].split("/")[-1]
def out_path_hash(context, parameters):
return parameters["output_path"] + f"_L{len(parameters['images'])}"
@task(
retries=5,
retry_delay_seconds=1,
cache_key_fn=task_input_hash,
cache_expiration=timedelta(minutes=5),
result_storage_key="{parameters[url]}",
)
def get_content(url: str, params: Dict[str, any] | None = None):
response = httpx.get(f"https://{url}", params=params)
try:
response.raise_for_status()
return response.content
except httpx.HTTPStatusError:
return None
def preview_urls(urls):
print("URLS (head):")
print(urls[:5])
print("URLS (tail):")
print(urls[-5:])
@task(
cache_key_fn=task_input_hash,
cache_expiration=timedelta(hours=1),
)
def get_images(urls: List[str] | List[str], limit: int = 0):
if limit > 0:
print(f"Limiting to {limit} urls")
urls = urls[-limit:]
urls = [url.replace("https://", "").replace("http://", "") for url in urls]
preview_urls(urls)
futures = get_content.map(urls)
images = [
(urls[i], f.result()) for i, f in enumerate(futures) if f.result() is not None
]
return images
def extract_timestamp_from_url(url: str) -> str:
# Assuming the timestamp format is in the format shown in the screenshot
match = re.search(r"\d{8}_\d{6}", url)
return match.group(0) if match else ""
# @task(
# cache_key_fn=out_path_hash,
# cache_expiration=timedelta(minutes=3),
# result_storage_key="{parameters[output_path]}",
# )
# def create_animation(
# images: List[bytes], output_path: str, duration: float = 0.5
# ) -> None:
# if not images:
# raise ValueError("No images!")
# pil_images = [Image.open(BytesIO(img_data)).convert("RGB") for img_data in images]
# imageio.mimsave(output_path, pil_images, duration=duration)
# return output_path
def make_even_dimensions(image):
width, height = image.size
if width % 2 == 1:
width -= 1
if height % 2 == 1:
height -= 1
return image.resize((width, height), Image.ANTIALIAS)
def crop_to_even(image):
width, height = image.size
# Adjust width and height to be even
if width % 2 == 1:
width -= 1
if height % 2 == 1:
height -= 1
return image.crop((0, 0, width, height))
@task(
cache_key_fn=out_path_hash,
cache_expiration=timedelta(hours=4),
result_storage_key="{parameters[output_path]}",
)
def create_mp4_animation(images: List[bytes], output_path: str, fps: int = 24) -> None:
# Convert bytes to PIL images and then to numpy arrays
frames = [
np.array(crop_to_even(Image.open(BytesIO(img_data)).convert("RGB")))
for img_data in images
]
# Create a video clip from the image sequence
clip = ImageSequenceClip(frames, fps=fps)
# Write the video clip to a file
clip.write_videofile(
output_path,
codec="libx264",
ffmpeg_params=["-pix_fmt", "yuv420p"],
preset="medium",
bitrate="800k",
)
return output_path
def format_output_name(url: str, latest: bool = False):
if latest:
now = "latest"
else:
now = datetime.now().strftime("%Y%m%d-%H:%M:%S")
return (
url.replace("https://", "")
.replace("http://", "")
.replace("/", "-")
.replace(".", "_")
+ now
)
@task(
name="animate",
retries=0,
retry_delay_seconds=1,
log_prints=True,
cache_key_fn=task_input_hash,
cache_expiration=timedelta(minutes=3),
)
def animate(
url: str = "https://services.swpc.noaa.gov/images/animations/geospace/density/",
ext: str = "png",
latest: bool = True,
limit: int = 0,
):
urls = get_file_links(url, ext)
urls = list(urls)
if len(urls) == 0:
raise ValueError("No urls scraped")
images = get_images(list(sorted(urls)), limit=limit)
if len(images) == 0:
raise ValueError("No images retrieved.")
print(f"Retrieved {len(images)} images.")
sorted_images = sorted(images, key=lambda x: extract_timestamp_from_url(x[0]))
print("Head:")
print([u for u, i in sorted_images[:5]])
frames = [s[1] for s in sorted_images]
# create_animation(frames, "out.gif", duration=5)
out_name = format_output_name(url, latest=latest)
create_mp4_animation(frames, f"out/{out_name}.mp4")
def deploy_name():
return datetime.utcnow().strftime("%Y-%m-%dT%H:%M:%S") + "Z"
@flow(
name="create-animations",
retries=0,
retry_delay_seconds=1,
log_prints=True,
flow_run_name=None,
timeout_seconds=90,
)
def create_animations(
url: str | List[str] = BASE_URL + "velocity/",
ext: str | None = None,
latest: bool = False,
limit: int = 0,
):
if isinstance(url, str):
url = [url]
futures = animate.map(url, ext, latest, limit)
return futures
if __name__ == "__main__":
# make_animation.from_source(
# source=TEST_REPO,
# entrypoint="noaa_animate.py:make_animation",
# ).deploy(
# name="noaa-animate", work_pool_name="process"
# )
from prefect.client.schemas.schedules import CronSchedule
sched = CronSchedule(cron="*/15 * * * *", timezone="America/Denver")
links = [
BASE_URL + "density/",
BASE_URL + "velocity/",
BASE_URL + "pressure/",
]
sched_params = {
"latest": True,
"url": links,
"ext": "png",
"limit": 0,
}
create_animations.serve(
"noaa-animate", limit=8, interval=None, parameters=sched_params
)
# make_animation(url)