Parsing text for elasticsearch index and grab index values - regex

Question

In the parts below, I need to pick out the first entry of the output for each section which in turn is the name of the index for ElasticSearch.
For instance nprod#n_docs, platform-api-stage, nprod#janeuk_classic, nprod#delista.com#1
So I know that they are between patterns of characters like
{ "
and a
: {
"settings" : {
So what would my script look like to grab these values so I can cat them out to another file?
My output looks like:
{
"nprod#n_docs" : {
"settings" : {
"index.analysis.analyzer.rwn_text_analyzer.char_filter" : "html_strip",
"index.analysis.analyzer.rwn_text_analyzer.language" : "English",
"index.translog.disable_flush" : "false",
"index.version.created" : "190199",
"index.number_of_replicas" : "1",
"index.number_of_shards" : "5",
"index.analysis.analyzer.rwn_text_analyzer.type" : "snowball",
"index.translog.flush_threshold_size" : "60",
"index.translog.flush_threshold_period" : "",
"index.translog.flush_threshold_ops" : "500"
}
},
"platform-api-stage" : {
"settings" : {
"index.analysis.analyzer.api_edgeNGram.type" : "custom",
"index.analysis.analyzer.api_edgeNGram.filter.0" : "api_nGram",
"index.analysis.filter.api_nGram.max_gram" : "50",
"index.analysis.analyzer.api_edgeNGram.filter.1" : "lowercase",
"index.analysis.analyzer.api_path.type" : "custom",
"index.analysis.analyzer.api_path.tokenizer" : "path_hierarchy",
"index.analysis.filter.api_nGram.min_gram" : "2",
"index.analysis.filter.api_nGram.type" : "edgeNGram",
"index.analysis.analyzer.api_edgeNGram.tokenizer" : "standard",
"index.analysis.filter.api_nGram.side" : "front",
"index.analysis.analyzer.api_path.filter.0" : "lowercase",
"index.number_of_shards" : "5",
"index.number_of_replicas" : "1",
"index.version.created" : "200599"
}
},
"nprod#janeuk_classic" : {
"settings" : {
"index.analysis.analyzer.n_text_analyzer.language" : "English",
"index.translog.disable_flush" : "false",
"index.version.created" : "190199",
"index.number_of_replicas" : "1",
"index.number_of_shards" : "5",
"index.analysis.analyzer.n_text_analyzer.char_filter" : "html_strip",
"index.analysis.analyzer.n_text_analyzer.type" : "snowball",
"index.translog.flush_threshold_size" : "60",
"index.translog.flush_threshold_period" : "",
"index.translog.flush_threshold_ops" : "500"
}
},
"nprod#delista.com#1" : {
"settings" : {
"index.analysis.analyzer.n_text_analyzer.language" : "English",
"index.translog.disable_flush" : "false",
"index.version.created" : "191199",
"index.number_of_replicas" : "1",
"index.number_of_shards" : "5",
"index.analysis.analyzer.n_text_analyzer.char_filter" : "html_strip",
"index.analysis.analyzer.n_text_analyzer.type" : "snowball",
"index.translog.flush_threshold_size" : "60",
"index.translog.flush_threshold_period" : "",
"index.translog.flush_threshold_ops" : "500"
}
},

Answer 1

That's JSON. Read the data and parse it using JSON::XS.
use JSON::XS qw( decode_json );
my $file;
{
open(my $fh, '<:raw', $qfn)
or die("Can't open \"$qfn\": $!\n");
local $/;
$file = <$fh>;
}
my $data = decode_json($file);
Then, just traverse the tree for the information you want.
my #index_names = keys(%$data);