Class: FlatKit::Command::Merge

Inherits:
FlatKit::Command show all
Defined in:
lib/flat_kit/command/merge.rb

Overview

Internal: The implementation of the merge command.

Instance Attribute Summary collapse

Attributes inherited from FlatKit::Command

#argv, #env, #logger, #opts, #readers, #writer

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from FlatKit::Command

for, #initialize, names

Methods included from DescendantTracker

#children, #find_child, #find_children, #inherited

Constructor Details

This class inherits a constructor from FlatKit::Command

Instance Attribute Details

#compare_keys ⇒ Object (readonly)

Returns the value of attribute compare_keys.



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# File 'lib/flat_kit/command/merge.rb', line 66

def compare_keys
  @compare_keys
end

Class Method Details

.description ⇒ Object 



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# File 'lib/flat_kit/command/merge.rb', line 13

def self.description
  "Merge sorted files together that have the same structure."
end

.name ⇒ Object 



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# File 'lib/flat_kit/command/merge.rb', line 9

def self.name
  "merge"
end

.parser ⇒ Object 



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# File 'lib/flat_kit/command/merge.rb', line 17

def self.parser
  ::Optimist::Parser.new do
    banner Merge.description.to_s
    banner ""

    banner <<~BANNER
      Given a set of input files that have the same structure, and are already
      sorted by a set of keys. The Merge command will merge all those files
      into a single output file.

      The --key parameter is required, and it must be a comma separated list
      of field nams on the input on which to use as the sort key for the merge
      process.

      There must also be at least 2 input files. Merging only 1 file into an
      output file is the same as the 'cat' command.

      The flatfile type(s) will be automatically determined by the file name.
      If the output is not a file, but to stdout then the output type will
      be the same as the first input file, or it can be specified as a commandline
      switch.

      The merge will do a single pass through the input to generate the
      output.
    BANNER

    banner <<~USAGE

      Usage:
        fk merge --key surname,given_name file1.csv file2.csv > all.csv
        fk merge --key surname,given_name --output-format json file1.csv file2.csv > all.json
        fk merge --key field1,field2 --output-format json input*.csv | gzip -c > all.json.gz
        fk merge --key field12 file*.json.gz -o all.json.gz

    USAGE

    banner <<~OPTIONS

      Options:

    OPTIONS

    opt :output, "Send the output to the given path instead of standard out.", default: "<stdout>"
    opt :input_format, "Input format, csv or json", default: "auto", short: :none
    opt :output_format, "Output format, csv or json", default: "auto", short: :none
    opt :key, "The comma separted list of field(s) to use for sorting the input", required: true, type: :string
  end
end

Instance Method Details

#call ⇒ Object 



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# File 'lib/flat_kit/command/merge.rb', line 84

def call
  @merge.call
end

#parse ⇒ Object 



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# File 'lib/flat_kit/command/merge.rb', line 68

def parse
  parser = self.class.parser
  ::Optimist.with_standard_exception_handling(parser) do
    @opts = parser.parse(argv)
    @compare_keys = CSV.parse_line(opts[:key])
    paths = parser.leftovers
    raise ::Optimist::CommandlineError, "At least 2 input files are required" if paths.size < 2

    @merge = ::FlatKit::Merge.new(inputs: paths, input_fallback: opts[:input_format],
                                  compare_fields: @compare_keys,
                                  output: opts[:output], output_fallback: opts[:output_format])
  rescue ::FlatKit::Error => e
    raise ::Optimist::CommandlineError, e.message
  end
end