Initial POC

default.nix

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+{ python3 }:
+with python3.pkgs;
+buildPythonPackage rec {
+  name = "tsplot";
+  src = ./.;
+  propagatedBuildInputs = [ pyyaml pandas dash ];
+  buildInputs = [];
+  doCheck = false;
+  shellHook = "";
+}

setup.py

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+#!/usr/bin/env python
+
+from distutils.core import setup
+
+setup(name='tsplot',
+      version='0.1',
+      description='Simple time series plotting',
+      author='0xee',
+      author_email='tsplot@0xee.eu',
+      packages=[],
+      scripts=['tsplot'])

shell.nix

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+{ pkgs ? import <nixpkgs> {} }:
+pkgs.callPackage ./. {}

tsplot

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+#!/usr/bin/env python
+
+from dash.dependencies import Input, Output
+import dash
+import dash_core_components as dcc
+import dash_html_components as html
+
+import pandas as pd
+from functools import lru_cache
+
+import argparse
+import sqlite3
+import time
+import sys
+import datetime
+
+external_stylesheets = ['https://codepen.io/chriddyp/pen/bWLwgP.css']
+
+app = dash.Dash(__name__, external_stylesheets=external_stylesheets)
+
+
+def get_topics(db):
+    cursor = db.cursor()
+    query = 'SELECT name FROM sqlite_master WHERE type="table"'
+    q = cursor.execute(query)
+    topics = [t[0] for t in q.fetchall()]
+    return topics
+
+
+update_interval_s = 4
+
+# Since we're adding callbacks to elements that don't exist in the app.layout,
+# Dash will raise an exception to warn us that we might be
+# doing something wrong.
+# In this case, we're adding the elements through a callback, so we can ignore
+# the exception.
+app.config.suppress_callback_exceptions = True
+
+app.layout = html.Div([
+    dcc.Location(id='url', refresh=False),
+    html.Div(id='page-content')
+])
+
+
+@lru_cache(maxsize=10)
+def get_data(topic, timerange, ts):
+    conn = sqlite3.connect(db)
+    table = topic
+
+    earliest = datetime.datetime.now() - timerange
+    query = f"SELECT * FROM {table} WHERE timestamp > '{earliest}'"
+
+    df = pd.read_sql(query, conn, parse_dates=[
+                     'timestamp'], index_col='timestamp')
+    return df
+
+
+plot_page = html.Div([
+    dcc.Interval(
+        id='interval-component',
+        interval=4*1000,  # in milliseconds
+        n_intervals=0),
+    dcc.Dropdown(
+        id='timerange',
+        options=[
+            {'label': 'Last hour', 'value': 'h'},
+            {'label': 'Last day', 'value': 'd'},
+            {'label': 'Last week', 'value': 'w'},
+            {'label': 'All', 'value': 'all'}
+        ],
+        value='d'
+    ),
+    dcc.Graph(id='graph', animate=False),
+    dcc.Link('Back', href='/')
+])
+
+def get_timedelta(range_str):
+    range_to_delta = {
+        'h': datetime.timedelta(hours=1),
+        'd': datetime.timedelta(days=1),
+        'w': datetime.timedelta(weeks=1),
+        'all': datetime.timedelta(weeks=10000),
+    }
+    return range_to_delta[range_str]
+
+
+@app.callback(Output('graph', 'figure'),
+              [Input('interval-component', 'n_intervals'),
+               Input('timerange', 'value'),
+               Input('url', 'pathname')])
+def update_graph(interval, timerange, pathname):
+    topics = pathname.strip('/').split('+')
+    if len(topics):
+        delta = get_timedelta(timerange)
+        now = int(time.time()) // update_interval_s
+        def make_data(df, name):
+            return {
+                'x': df.index,
+                'y': df['value'],
+                'type': 'scatter',
+                'mode': 'lines',
+                'name': name
+            }
+        return {
+            'data': [make_data(get_data(topic, delta, now), topic) for topic in topics]}
+    else:
+        return {}
+
+# Update the index
+@app.callback(dash.dependencies.Output('page-content', 'children'),
+              [dash.dependencies.Input('url', 'pathname')])
+def display_page(pathname):
+    if pathname == '/':
+        return index_page
+    else:
+        return plot_page
+    # You could also return a 404 "URL not found" page here
+
+
+if __name__ == '__main__':
+
+    options = argparse.ArgumentParser()
+    options.add_argument('--debug', '-d', action='store_true')
+    options.add_argument('db')
+
+    args = options.parse_args()
+
+    db = args.db
+
+    conn = sqlite3.connect(db)
+    topics = get_topics(conn)
+
+    index_page = html.Div(sum([[
+        dcc.Link(f'Go to {page}', href=f'/{page}'),
+        html.Br()] for page in topics], []))
+
+    app.run_server(debug=args.debug, host='0.0.0.0')