Re: Paws result how to process?

[Lotus1]

It looks like in Paws::CloudWatch::DescribeAlarmsOutput it tells you that object contains an attribute that holds an arrayref where each element of the array is an object of the type Paws::CloudWatch::MetricAlarm. So you can deref the arrayref and loop through with foreach and inspect the attributes of MetricAlarm.

Update: Try this to see what you get.

2nd Update: I forgot to access the attribute MetricAlarms. This is all untested but should give you an idea.

3rd Update: Added print AlarmName attribute.

Update: Fixed brackets after @.

sub describe_alarms {
    my ($alarm_name_prefix) = @_;
    my $obj = Paws->service( 'CloudWatch', region => 'us-east-1' );
    my $result = $obj->DescribeAlarms(
        AlarmNamePrefix => $alarm_name_prefix,

    );
    
    #foreach(@$result){    Updated
    foreach( @{ $result->MetricAlarms } ){

        print "-"x79,"\n";
        print "**AlarmName** : ", $_->AlarmName,"\n";
        print Dumper($_);
    }
    print "\n***\n--number of elements: ", scalar @{ $result->MetricAl
+arms }, "\n";
    return $result;
}

[bigswifty00000]

I must be missing something....

Thanks again for the help!

below is the dump from Data::Dumper

and the modified function produces these errors....

ERRORS:
Scalar found where operator expected at ./describe_alarms.pl line 97, 
+near
    "@($result" (#1)
    (S syntax) The Perl lexer knows whether to expect a term or an ope
+rator.
    If it sees what it knows to be a term when it was expecting to see
+ an
    operator, it gives you this warning.  Usually it indicates that an
    operator or delimiter was omitted, such as a semicolon.
    
    (Missing operator before $result?) (#2)
    (S syntax) This is an educated guess made in conjunction with the 
+message
    "%s found where operator expected".  Often the missing operator is
+ a comma.
    
syntax error at ./describe_alarms.pl line 97, near "@($result"
Execution of ./describe_alarms.pl aborted due to compilation errors (#
+3)
    (F) Probably means you had a syntax error.  Common reasons include
+:
    
        A keyword is misspelled.
        A semicolon is missing.
        A comma is missing.
        An opening or closing parenthesis is missing.
        An opening or closing brace is missing.
        A closing quote is missing.
    
    Often there will be another error message associated with the synt
+ax
    error giving more information.  (Sometimes it helps to turn on -w.
+)
    The error message itself often tells you where it was in the line 
+when
    it decided to give up.  Sometimes the actual error is several toke
+ns
    before this, because Perl is good at understanding random input.
    Occasionally the line number may be misleading, and once in a blue
+ moon
    the only way to figure out what's triggering the error is to call
    perl -c repeatedly, chopping away half the program each time to se
+e
    if the error went away.  Sort of the cybernetic version of 20 ques
+tions.
    
Uncaught exception from user code:
    syntax error at ./describe_alarms.pl line 97, near "@($result"
    Execution of ./describe_alarms.pl aborted due to compilation error
+s.

MODIFIED FUNCTION:

sub describe_alarms {
    my ($alarm_name_prefix) = @_;
    my $result;
    my $obj = Paws->service( 'CloudWatch', region => 'us-east-1' );
    $result = $obj->DescribeAlarms(
        AlarmNamePrefix => $alarm_name_prefix,

    );
# print Dumper($result);
print Dumper(ref @($result->MetricAlarms));
#print Dumper(@($result->MetricAlarms));

exit;
=pod
 foreach ( @($result->MetricAlarms) ){

        print "-"x79,"\n";
        print "**AlarmName** : ", $_->AlarmName,"\n";
        print Dumper($_);
    }
    print "\n***\n--number of elements: ", scalar @($result->MetricAla
+rms), "\n";
    #return $result;

=cut
    return $result;
}

DUMP:
$VAR1 = bless(
    {
        '_request_id'  => '3eeadc30-9588-11e8-9cf2-e1b5a579da44',
        'MetricAlarms' => [
            bless(
                {
                    'AlarmArn' =>
'arn:aws:cloudwatch:us-east-1:xxxxxxxxxxxxx:alarm:pubtech-best-gte-90-
+dev',
                    'StateReason' =>
'Threshold Crossed: 1 out of the last 2 datapoints [0.152614819450015 
+(01/08/18 11:31:00)] was not greater than or equal to the threshold (
+90.0) (minimum 1 datapoint for ALARM -> OK transition).',
                    'AlarmActions' => [
'arn:aws:sns:us-east-1:xxxxxxxx:bestsellers_prd_best-alarm2'
                    ],
                    'AlarmName' => 'pubtech-best-gte-90-dev',
                    'AlarmDescription' =>
                      'Alarm when volume is greater than or equal 90 p
+ercent',
                    'Period'         => '300',
                    'ActionsEnabled' => 1,
                    'Dimensions'     => [
                        bless(
                            {
                                'Name'  => 'Filesystem',
                                'Value' => '/dev/xvdf'
                            },
                            'Paws::CloudWatch::Dimension'
                        ),
                        bless(
                            {
                                'Name'  => 'MountPath',
                                'Value' => '/best'
                            },
                            'Paws::CloudWatch::Dimension'
                        ),
                        bless(
                            {
                                'Value' => 'xxxxxxxxxxxxxxx',
                                'Name'  => 'InstanceId'
                            },
                            'Paws::CloudWatch::Dimension'
                        )
                    ],
                    'Statistic'          => 'Average',
                    'Threshold'          => '90.0',
                    'DatapointsToAlarm'  => '2',
                    'Namespace'          => 'System/Linux',
                    'ComparisonOperator' => 'GreaterThanOrEqualToThres
+hold',
                    'StateReasonData' =>
'{"version":"1.0","queryDate":"2018-08-01T11:36:17.049+0000","startDat
+e":"2018-08-01T11:31:00.000+0000","statistic":"Average","period":300,
+"recentDatapoints":[0.152614819450015],"threshold":90.0}',
                    'StateValue'            => 'OK',
                    'StateUpdatedTimestamp' => '2018-08-01T11:36:17.06
+2Z',
                    'EvaluationPeriods'     => '2',
                    'TreatMissingData'      => 'missing',
                    'MetricName'            => 'DiskSpaceUtilization',
                    'AlarmConfigurationUpdatedTimestamp' =>
                      '2018-07-12T14:40:07.798Z'
                },
                'Paws::CloudWatch::MetricAlarm'
            )
        ]
    },
    'Paws::CloudWatch::DescribeAlarmsOutput'
);

[Lotus1]

It was untested code so I messed up the brackets to the right of '@'. It needs to be curly braces '{}' in that case.

    foreach( @{$result->MetricAlarms} ){

        print "-"x79,"\n";
        print "**AlarmName** : ", $_->AlarmName,"\n";
        print Dumper($_);
    }
    print "\n***\n--number of elements: ", scalar @{$result->MetricAla
+rms}, "\n";

Alternatively you can use an intermediate variable to hold the array ref before de-referencing it.

my $ar_ref = $result->MetricAlarms;
foreach( @$ar_ref ){
...

This article shows how to use the curly braces for dereferencing things. Also have a look at this node and this article in the Perl docs.

[bigswifty00000]

I had replaced curly braces, but still didn't seem to work, but it does now!!

Thanks Again!

[bigswifty00000]

Thanks for the reply, I'll try it today!