Couldn't find foreign struct converter for 'cairo.Context'

Question

It's me again. This is a code related to a project I'm doing called Sentiment Analysis on Twitter Data. The following code is basically used to display the number of positive and negative tweets in which I'm getting the error given below.

from pyspark import SparkConf, SparkContext
from pyspark.streaming import StreamingContext
from pyspark.streaming.kafka import KafkaUtils
import operator
import numpy as np
import matplotlib.pyplot as plt


def main():
        conf = SparkConf().setMaster("local[2]").setAppName("Streamer")
        sc = SparkContext(conf=conf)

        # Creating a streaming context with batch interval of 10 sec
        ssc = StreamingContext(sc, 10)
        ssc.checkpoint("checkpoint")
        pwords = load_wordlist("positive.txt")
        nwords = load_wordlist("negative.txt")
        counts = stream(ssc, pwords, nwords, 100)
        make_plot(counts)


def make_plot(counts):
        """
        This function plots the counts of positive and negative words for each timestep.
        """
        positiveCounts = []
        negativeCounts = []
        time = []

        for val in counts:
        positiveTuple = val[0]
        positiveCounts.append(positiveTuple[1])
        negativeTuple = val[1]
        negativeCounts.append(negativeTuple[1])

        for i in range(len(counts)):
        time.append(i)

        posLine = plt.plot(time, positiveCounts,'bo-', label='Positive')
        negLine = plt.plot(time, negativeCounts,'go-', label='Negative')
        plt.axis([0, len(counts), 0, max(max(positiveCounts), max(negativeCounts))+50])
        plt.xlabel('Time step')
        plt.ylabel('Word count')
        plt.legend(loc = 'upper left')
    plt.show()


def load_wordlist(filename):
    """ 
    This function returns a list or set of words from the given filename.
    """ 
    words = {}
    f = open(filename, 'rU')
    text = f.read()
    text = text.split('\n')
    for line in text:
        words[line] = 1
    f.close()
    return words


def wordSentiment(word,pwords,nwords):
    if word in pwords:
    return ('positive', 1)
    elif word in nwords:
    return ('negative', 1)


def updateFunction(newValues, runningCount):
    if runningCount is None:
       runningCount = 0
    return sum(newValues, runningCount) 


def sendRecord(record):
    connection = createNewConnection()
    connection.send(record)
    connection.close()


def stream(ssc, pwords, nwords, duration):
    kstream = KafkaUtils.createDirectStream(
    ssc, topics = ['twitterstream'], kafkaParams = {"metadata.broker.list": 'localhost:9092'})
    tweets = kstream.map(lambda x: x[1].encode("ascii", "ignore"))

    # Each element of tweets will be the text of a tweet.
    # We keep track of a running total counts and print it at every time step.
    words = tweets.flatMap(lambda line:line.split(" "))
    positive = words.map(lambda word: ('Positive', 1) if word in pwords else ('Positive', 0))
    negative = words.map(lambda word: ('Negative', 1) if word in nwords else ('Negative', 0))
    allSentiments = positive.union(negative)
    sentimentCounts = allSentiments.reduceByKey(lambda x,y: x+y)
    runningSentimentCounts = sentimentCounts.updateStateByKey(updateFunction)
    runningSentimentCounts.pprint()

    # The counts variable hold the word counts for all time steps
    counts = []
    sentimentCounts.foreachRDD(lambda t, rdd: counts.append(rdd.collect()))

    # Start the computation
    ssc.start() 
    ssc.awaitTerminationOrTimeout(duration)
    ssc.stop(stopGraceFully = True)

    return counts


if __name__=="__main__":
    main()

The error happens to be as follows:

Traceback (most recent call last):
  File "/usr/local/lib/python2.7/dist-packages/matplotlib/backends/backend_gtk3.py", line 343, in idle_draw
    self.draw()
  File "/usr/local/lib/python2.7/dist-packages/matplotlib/backends/backend_gtk3.py", line 336, in draw
    self.get_property("window").process_updates (False)
TypeError: Couldn't find foreign struct converter for 'cairo.Context'

score 28 · Accepted Answer · answered Mar 26 '18 at 22:31

28

See this Github discussion. For example try:

sudo apt-get install python-gi-cairo

answered Mar 26 '18 at 22:31

Burrough Clarke

522
4
19

Many thanks, this made meld start working again (it was issuing the same error message). – Terry Brown Oct 04 '18 at 14:10
15

If you use python3, you may need to install `python3-gi-cairo` package instead. – Jan Spurny Mar 10 '20 at 12:16
2

For Fedora, try `dnf install python3-gobject` – haolee Jul 09 '20 at 13:47

score 10 · Answer 2 · answered Nov 15 '20 at 21:28

10

replying to above comment, 3 year forward (I'm using WSL 2 and VSCode, and X-server for GUI applications), you should use

sudo apt install python3-gi-cairo

and you are saved the hassle of changings backends.

answered Nov 15 '20 at 21:28

Muhammad Salman Afzal

159
1
2
10

score 4 · Answer 3 · answered Aug 11 '21 at 23:53

4

In my case, python3-gi-cairo is already installed but possibly broken. So if anyone meets this case, you simply can add --reinstall in the apt install.

sudo apt install --reinstall python3-gi-cairo

Reinstall here won't break your system as when you remove (all dependants will be removed too) then installing it again.

answered Aug 11 '21 at 23:53

fsevenm

791
8
19

Helped me as well. – lnstadrum Mar 25 '22 at 19:07

score 2 · Answer 4 · answered May 02 '17 at 15:00

The problem here is matplotlib's backend GTK3. I recommend changing it to a backend that just works for you. See https://matplotlib.org/faq/usage_faq.html

I usually do

import matplotlib
matplotlib.use('Agg')

before any import related to matplotlib. You won't be able to see the figure but you can save it with savefig() and then open it with your image viewer.

Couldn't find foreign struct converter for 'cairo.Context'

4 Answers4