data api

An in-memory key-value cache that follows the
Cache-Aside caching model and also persists to local disk.
Value types supported: Pandas DataFrames, Json, Collections. Deploys to AWS, containers, and local workstations.

function api

nomenclature

system of record (SOR) - primary data source
cache - fast access copy of SOR data
data locality - co-location of data and compute resources. shared memory.

env vars

LOCAL_DATA_DIR   # cache root path in a container or development machine  
AWS_BUCKET_NAME  # System of Record AWS S3 bucket 
AWS_DATA_DIR     # System of Record AWS root path 
AWS ACCESS KEYS  # System of Record AWS IAM keys 

run api server

python local_flask_rest_server.py

create cache from s3 objects

curl  http://127.0.0.1:5000/cache/api/v1.0/?function=create\&path=file1.snappy.parquet

{
    "return": {
        "uri": "/cache/api/v1.0/",
        "path": "file1.snappy.parquet",
        "value": "{'result': 'success'}"
    }
}

create functions

def main(cache, **args, **kwargs):

run the functions on the cache

time curl  http://127.0.0.1:5000/cache/api/v1.0/?function=cache_item_stats\&key=file1.snappy.parquet | sed 's/\\n/\n/g'

  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100   513  100   513    0     0  19730      0 --:--:-- --:--:-- --:--:-- 19730
{
    "return": {
        "uri": "/cache/api/v1.0/",
        "value": "(                   cusip  price  security_type trade_date
0                  Unit:    NaN            NaN       None
1            Multiplier:   1.00            NaN       None
2              Currency:    NaN            NaN       None
3    Unique Identifier:     NaN            NaN       None
4            Time Period    NaN            NaN       None
..                   ...    ...            ...        ...
776              2017-07   2.32            NaN       None
777              2017-08   2.21            NaN       None
778              2017-09   2.20            NaN       None
779              2017-10   2.36            NaN       None
780              2017-11   2.35            NaN       None

[781 rows x 4 columns], \"<class 'pandas.core.frame.DataFrame'>\
RangeIndex: 781 entries, 0 to 780\
Data columns (total 4 columns):\
 #   Column         Non-Null Count  Dtype  \
---  ------         --------------  -----  \
 0   cusip          781 non-null    object \
 1   price          777 non-null    float64\
 2   security_type  0 non-null      float64\
 3   trade_date     0 non-null      object \
dtypes: float64(2), object(2)\
memory usage: 24.5+ KB\

GET parameters

# cache management 
create     same as read
read       function=read&path=file1.json
update     same as delete + read   
delete     function=delete&path=file1.json
head       function=head&path=file1.json

# function execution
function   function=function_name
parameter parameter_name=parameter_value

POST form

{
    "data": {
    "function" = "read",
    "path" = "file1.json"
    }
}

{
    "data": {
    "function" = "function_name",
    "parameter_name" = "parameter_value"
    }
}

use case

roadmap cache futures

• data spec file
• thread_pool
• @compute_result, @sql_result
• @lru_cache
• eviction policy