kafka_lags.py

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Licensed under the Apache License, Version 2.0 (the “License”); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an “AS IS” BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

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Plot graph with Kafka lags with linear regression line added into plot.

Source CSV file is to be retrieved from Grafana.

Usage:

kafka_lags.py input_file.csv

Example:

kafka_lags.py overall.csv”)

import sys
import pandas as pd
import numpy as np
import matplotlib.pyplot as plt

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Standard moving average window

sma_window = 50

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Check if command line argument is specified (it is mandatory).

if len(sys.argv) < 2:
    print("Usage:")
    print("  plot_kafka_lags_pandas.py input_file.csv")
    print("Example:")
    print("  plot_kafka_lags_pandas.py overall.csv")
    sys.exit(1)

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First command line argument should contain name of input CSV.

input_csv = sys.argv[1]

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Try to open the CSV file specified.

df = pd.read_csv(input_csv)

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Add a standard moving average column

df['SMA'] = df.iloc[:, 1].rolling(window=sma_window).mean()

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Print the data frame and its description as well

print(df.info())
print()
print(df.describe())

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Values to be plotted

time = df["Time"]
messages = df["topic : uploads"]
sma = df["SMA"]

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Linear regression

x = np.arange(0, len(messages))
coef = np.polyfit(x, messages, 1)
poly1d_fn = np.poly1d(coef)

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Create new graph

plt.plot(messages, "-", poly1d_fn(np.arange(0, len(messages))), 'r-')

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Title of a graph

plt.title("Messages in Kafka")

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Add a label to x-axis

plt.xlabel("Time")

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Add a label to y-axis

plt.ylabel("Messages")

plt.legend(loc="upper right")

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Set the plot layout

plt.tight_layout()

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And save the plot into raster format and vector format as well

plt.savefig("kafka_lags_pandas.png")
plt.savefig("kafka_lags_pandas.svg")

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Try to show the plot on screen

plt.show()

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