def _get_zip_code_data(zip_code, utc_dt):
db_zip_read = table.get_item(
Key={"PartitionKey": "ZipCode:{}".format(zip_code)})
logger.info("DynamoDB ZipCode read response: {}".format(db_zip_read))
data = None
if "Item" not in db_zip_read or (utc_dt - parser.parse(
db_zip_read["Item"]["LastUpdated"])).total_seconds() > 3600:
if "Item" in db_zip_read:
metricutils.increment("aqi_GET.zip-code-cache-expired")
logger.info(
"Cached ZipCode value expired, requesting latest AirNow API data"
)
# We're still storing off the expired cached value here, in case
# AirNow API is overloaded and our request fails
data = db_zip_read["Item"]
else:
logger.info("No ZipCode value found, querying AirNow API for data")
metricutils.increment("aqi_GET.airnowapi-request")
data = _airnow_api_request(zip_code, utc_dt, data)
else:
metricutils.increment("aqi_GET.zip-code-cache-fallback")
logger.info("Cached ZipCode value less than an hour old, using that")
data = db_zip_read["Item"]
return data
def lambda_handler(event, context):
logger.info("Event: {}".format(event))
query_string = event["params"]["querystring"]
logger.info("Query String: {}".format(query_string))
metricutils.increment("inbound_POST.request")
data = parse.parse_qs(event["body-json"])
phone_number = data["From"][0]
body = data["Body"][0]
logger.info("Received \"{}\" from {}".format(body, phone_number))
zip_code = body.lower().strip()
include_map = "map" in zip_code
# Check to ensure the message is valid (a zip code with an optional "map" at the end)
if not re.match(r"^\d+(( )?map)?$", zip_code):
metricutils.increment("inbound_POST.help-response")
return _get_response(
"Send us a zip code and we'll reply with the area's Air Quality Index (AQI). Put \"map\" at the end and we'll include the regional map too."
)
if include_map:
metricutils.increment("inbound_POST.map-requested")
logger.info("Map requested")
zip_code = zip_code.split("map")[0].strip()
try:
response = requests.get("{}/aqi?zipCode={}".format(
AIR_QUALITY_API_URL, zip_code,
timeout=_AIR_QUALITY_API_TIMEOUT)).json()
except requests.exceptions.RequestException as e:
metricutils.increment("inbound_POST.error.aqi-request-failed")
logger.error(e)
response = {
"errorMessage":
"Oops, an unknown error occurred. AirNow may be overloaded at the moment."
}
logger.info("Response from `/aqi`: {}".format(response))
if "errorMessage" in response:
return _get_response(response["errorMessage"])
parameter_name = None
if "PM2.5" in response:
parameter_name = "PM2.5"
elif "PM10" in response:
parameter_name = "PM10"
if parameter_name is None:
metricutils.increment("inbound_POST.error.no-pm")
return _get_response(
"Oops, something went wrong. AirNow seems overloaded at the moment."
)
else:
# Clean up the time format
suffix = "PM" if response[parameter_name][
"HourObserved"] >= 12 else "AM"
time = response[parameter_name]["HourObserved"] - 12 if response[parameter_name]["HourObserved"] > 12 else \
response[parameter_name]["HourObserved"]
time = str(int(12 if time == "00" else time)
) + suffix + " " + response[parameter_name]["LocalTimeZone"]
msg = "{} AQI of {} {} for {} at {}. {}\nSource: AirNow".format(
response[parameter_name]["Category"]["Name"],
int(response[parameter_name]["AQI"]), parameter_name,
response[parameter_name]["ReportingArea"], time,
_AQI_MESSAGES[response[parameter_name]["Category"]["Name"]])
media = None
if include_map:
if "MapUrl" in response[parameter_name]:
media = response[parameter_name]["MapUrl"]
else:
metricutils.increment("inbound_POST.warn.map-request-failed")
logger.info(
"Map requested but not included, no MapUrl provided from AirNow"
)
return _get_response(msg, media)
def lambda_handler(event, context):
logger.info("Event: {}".format(event))
query_string = event["params"]["querystring"]
logger.info("Query String: {}".format(query_string))
metricutils.increment("aqi_GET.request")
zip_code = query_string["zipCode"]
utc_dt = datetime.utcnow()
zip_code_data = _get_zip_code_data(zip_code, utc_dt)
if zip_code_data is not None:
parameter_name = None
if "PM2.5" in zip_code_data:
parameter_name = "PM2.5"
elif "PM10" in zip_code_data:
parameter_name = "PM10"
if parameter_name is None:
metricutils.increment("aqi_GET.zip-code-unavailable")
data = {
"errorMessage":
"Sorry, AirNow data is unavailable for this zip code."
}
else:
data = zip_code_data.copy()
reporting_area_data = _get_reporting_area_data(
zip_code_data, parameter_name, utc_dt)
if reporting_area_data is not None:
# If the ReportingArea's CachedAQI is more recent than the ZipCode value (i.e. the cache is old and a new
# request failed), fallback to the ReportArea's cache (assuming it isn't more than a day old)
if parser.parse(reporting_area_data["LastUpdated"]) > parser.parse(zip_code_data["LastUpdated"]) and \
"CachedAQI" in reporting_area_data and \
parser.parse(reporting_area_data["CachedAQI"]["LastUpdated"]) < utc_dt + timedelta(
hours=24):
metricutils.increment(
"aqi_GET.reporting-area-cache-fallback")
logger.info(
"ReportingArea cached data is more recent, using that")
data = reporting_area_data["CachedAQI"]
data["MapUrl"] = reporting_area_data["MapUrl"]
else:
logger.info(
"ReportingArea was not cached and failed to query, no map data available"
)
else:
data = {
"errorMessage":
"Oops, something went wrong. AirNow seems overloaded at the moment."
}
data.pop("PartitionKey", None)
data.pop("LastUpdated", None)
data.pop("TTL", None)
if "MapUrl" in data:
for key, value in data.items():
if key == "MapUrl":
continue
value["MapUrl"] = data["MapUrl"]
data.pop("MapUrl")
return data
def _get_reporting_area_data(zip_code_data, parameter_name, utc_dt):
db_reporting_area_read = table.get_item(
Key={
"PartitionKey":
"ReportingArea:{}|{}".format(
zip_code_data[parameter_name]["ReportingArea"],
zip_code_data[parameter_name]["StateCode"])
})
logger.info("DynamoDB ReportingArea read response: {}".format(
db_reporting_area_read))
data = None
if "Item" not in db_reporting_area_read or (utc_dt - parser.parse(
db_reporting_area_read["Item"]["LastUpdated"])
).total_seconds() > 3600:
if "Item" in db_reporting_area_read and parser.parse(
zip_code_data["LastUpdated"]) > parser.parse(
db_reporting_area_read["Item"]["LastUpdated"]):
metricutils.increment("aqi_GET.airnow-request")
logger.info(
"Cached ReportingArea value expired, using latest ZipCode data"
)
data = db_reporting_area_read["Item"]
data["CachedAQI"] = zip_code_data.copy()
data["LastUpdated"] = utc_dt.isoformat()
db_reporting_area_update = table.update_item(
Key={
"PartitionKey":
"ReportingArea:{}|{}".format(
zip_code_data[parameter_name]["ReportingArea"],
zip_code_data[parameter_name]["StateCode"])
},
UpdateExpression="set LastUpdated = :dt, CachedAQI = :aqi",
ExpressionAttributeValues={
":dt": data["LastUpdated"],
":aqi": data["CachedAQI"]
},
ReturnValues="UPDATED_NEW")
logger.info("DynamoDB ReportingArea update response: {}".format(
db_reporting_area_update))
elif "Item" not in db_reporting_area_read:
logger.info(
"No ReportingArea value found, querying AirNow for data")
try:
metricutils.increment("aqi_GET.airnow-request")
response = requests.get(AIRNOW_URL.format(
zip_code_data["PartitionKey"][len("ZipCode") + 1:]),
timeout=_AIRNOW_TIMEOUT)
if AIRNOW_MAP_URL_PREFIX in response.text:
map_url = response.text[response.text.
find(AIRNOW_MAP_URL_PREFIX):]
map_url = map_url[0:map_url.find(".jpg") + 4]
data = {
"MapUrl":
map_url,
"CachedAQI":
zip_code_data.copy(),
"PartitionKey":
"ReportingArea:{}|{}".format(
zip_code_data[parameter_name]["ReportingArea"],
zip_code_data[parameter_name]["StateCode"]),
"LastUpdated":
utc_dt.isoformat()
}
db_reporting_area_write = table.put_item(Item=data)
logger.info(
"DynamoDB ReportingArea write response: {}".format(
db_reporting_area_write))
except requests.exceptions.ConnectionError as e:
# We don't retry these as they're expensive and infrequent, and
# once we have the URL for the ReportingArea map, it doesn't expire
metricutils.increment("aqi_GET.warn.airnow-connection")
logger.error(e)
logger.info(
"AirNow request timed out, map will be unavailable for this ReportingArea"
)
else:
logger.info(
"Cached ReportingArea value less than an hour old, using that")
data = db_reporting_area_read["Item"]
logger.info("Response data: {}".format(data))
return data
def _airnow_api_request(zip_code, utc_dt, data, retries=0):
airnow_api_key = random.choice(AIRNOW_API_KEYS)
logger.info("AirNow API URL: {}".format(
AIRNOW_API_URL.format(zip_code, airnow_api_key)))
try:
response = requests.get(AIRNOW_API_URL.format(zip_code,
airnow_api_key),
timeout=_AIRNOW_API_TIMEOUT)
logger.info("AirNow API response: {}".format(response.text))
response_json = response.json()
if response.status_code != 200:
return data
# If a cached value already exists, we want to update that instead
if data is None:
data = {}
for parameter in response_json:
parameter["DateObserved"] = parameter["DateObserved"].strip()
parameter["Longitude"] = Decimal(str(parameter["Longitude"]))
parameter["Latitude"] = Decimal(str(parameter["Latitude"]))
data[parameter["ParameterName"]] = parameter
if "PM2.5" in data or "PM10" in data:
data["PartitionKey"] = "ZipCode:{}".format(zip_code)
data["LastUpdated"] = utc_dt.isoformat()
data["TTL"] = int((utc_dt + timedelta(hours=24) -
datetime.fromtimestamp(0)).total_seconds())
db_zip_write = table.put_item(Item=data)
logger.info(
"DynamoDB ZipCode write response: {}".format(db_zip_write))
else:
logger.info(
"AirNow data is unavailable for this zip code, not caching")
except requests.exceptions.RequestException as e:
metricutils.increment("aqi_GET.warn.airnowapi-connection")
logger.error(e)
if retries < _AIRNOW_API_RETRIES:
metricutils.increment("aqi_GET.airnowapi-retry")
logger.info("Retrying AirNow API request ...")
time.sleep(_AIRNOW_API_RETRY_DELAY)
_airnow_api_request(zip_code, utc_dt, data, retries + 1)
elif data is not None:
metricutils.increment(
"aqi_GET.warn.airnowapi-zip-code-cache-fallback")
logger.info(
"AirNow API request timed out, falling back to cached value.")
except ValueError as e:
metricutils.increment("aqi_GET.error.airnowapi-response")
logger.error(e)
logger.info("AirNow API returned invalid JSON.")
return data
