MareArts Computer Vision Study.

TeamViewer, can't access remote computer on ubuntu after a reboot

February 19, 2021

It works for me.

sudo gedit /etc/gdm3/custom.conf

Uncomment this line in custom.conf file:

WaylandEnable=false

and Reboot.

Importerror: libgl.so.1: cannot open shared object file: no such file or directory opencv error

January 29, 2021

Try this one first:

pip install opencv-python--headless

install follow in case centos or aws linux docker

RUN yum install whatprovides libGL.so.1 -y

install follow in case linux docker

ENV TZ=Europe/Minsk
RUN ln -snf /usr/share/zoneinfo/$TZ /etc/localtime && echo $TZ > /etc/timezone
RUN apt-get install libgtk2.0-dev -y

Thank you, Good luck!

AWS dynamoDB, search item by condition in 3 ways

January 26, 2021

Most secure way is 3rd, first and second way can fail when items are many.

code start

#pre define
UID_common = '24dea8d41ef74efda24a4b37805fe6de'

#### way 1 ###
dynamodb_resource = boto3.resource('dynamodb')
docs_table = dynamodb_resource.Table(DOCUMENTS_TABLE_NAME)
resp = docs_table.scan(FilterExpression = Attr('UID_COMMON').eq(UID_common))
for item in resp['Items']:
    print( item['UID'] )

#### pre-define ###
dynamo_client = boto3.client('dynamodb', 
    aws_access_key_id = ACCESS_KEY,
    aws_secret_access_key = SECRET_KEY,
    region_name = REGION 
)

#### way 2 ###
response = dynamo_client.scan(
    TableName = DOCUMENTS_TABLE_NAME,
    ExpressionAttributeValues={':search':{'S': UID_common} },
    FilterExpression = "UID_COMMON = :search"
    )
for item in response['Items']:
    print(item['UID']['S'] )

### way 3 ###
paginator = dynamo_client.get_paginator('scan')
operation_parameters = {
  'TableName': DOCUMENTS_TABLE_NAME,
  'FilterExpression': 'UID_COMMON = :search',
  'ExpressionAttributeValues': {
    ':search': {'S': UID_common},
  }
}

page_iterator = paginator.paginate(**operation_parameters)
for page in page_iterator:
    for item in page['Items']:
        print( item['UID']['S'] )

code end

Enjoy AWS!