WIP: implement basic features

Signed-off-by: Daijiro Fukuda <fukuda@clear-code.com>

Author: daipom

.github/workflows/main.yml

@@ -44,4 +44,6 @@ jobs:
         run: rake install
       - name: Run exe
         run: |
-          tailcheck
+          tailcheck --version
+          tailcheck --help
+          tailcheck test/data/pos1 test/data/not-exist test/data/pos2

exe/tailcheck

@@ -3,7 +3,5 @@
 
 require 'fluent/tail_checker'
 
-puts Fluent::TailChecker::VERSION
-
 command = Fluent::TailChecker::TailCheck.new
 exit(command.run)

lib/fluent/tail_checker/pos.rb

@@ -0,0 +1,59 @@
+# frozen_string_literal: true
+
+# Copyright 2025 Daijiro Fukuda
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+module Fluent
+  module TailChecker
+    UNWATCHED_POSITION = 0xffffffffffffffff
+    POSITION_FILE_ENTRY_REGEX = /^([^\t]+)\t([0-9a-fA-F]+)\t([0-9a-fA-F]+)/
+
+    class PosFile
+      attr_reader :entries
+
+      def initialize(path)
+        @entries = PosFile.load_entries(path)
+      end
+
+      def self.load_entries(path)
+        entries = []
+
+        File.open(path, File::RDONLY|File::BINARY) do |file|
+          file.each_line do |line|
+            m = POSITION_FILE_ENTRY_REGEX.match(line)
+            next if m.nil?
+
+            entries << PosEntry.new(
+              m[1],
+              m[2].to_i(16),
+              m[3].to_i(16),
+            )
+          end
+        end
+
+        entries
+      end
+    end
+
+    class PosEntry
+      attr_reader :path, :pos, :ino
+
+      def initialize(path, pos, ino)
+        @path = path
+        @pos = pos
+        @ino = ino
+      end
+    end
+  end
+end

lib/fluent/tail_checker/tail_check.rb

@@ -14,14 +14,62 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+require "optparse"
+
+require_relative "pos"
+
 module Fluent
   module TailChecker
     class TailCheck
-      def run
-        # TODO
-        puts "TailCheck command run."
+      def initialize
+        @pos_filepaths = []
+      end
+
+      def run(argv=ARGV)
+        parse_command_line(argv)
+        check
         true
       end
+
+      def parse_command_line(argv)
+        parser = OptionParser.new
+        parser.version = VERSION
+        parser.banner = <<~BANNER
+          Usage: tailcheck pos_file [pos_file2 ...]
+          Example: tailcheck /path/to/pos1 /path/to/pos2
+
+        BANNER
+
+        raw_paths = parser.parse(argv)
+        @pos_filepaths = validate_paths(raw_paths).to_a
+      end
+
+      def validate_paths(paths)
+        Enumerator.new do |y|
+          paths.each do |path|
+            unless FileTest.exist?(path)
+              $stderr.puts "File does not exist. Skipped. Path: #{path}"
+              next
+            end
+
+            y << path
+          end
+        end
+      end
+
+      def check
+        @pos_filepaths.each do |path|
+          check_pos(path)
+        end
+      end
+
+      def check_pos(path)
+        posfile = PosFile.new(path)
+        # TODO
+        p posfile
+      rescue => e
+        $stderr.puts "Can not open the file. Skipped. Path: #{path}, Error: #{e}"
+      end
     end
   end
 end

test/data/pos1

@@ -0,0 +1,2 @@
+/test/test.log	0000000000000008	00000000060e378c
+/test/test.log	0000000000000000	0000000000000000

test/data/pos2

@@ -0,0 +1,3 @@
+/test/test.log	ffffffffffffffff	00000000060e3795
+/test/test.log	ffffffffffffffff	00000000060e3796
+/test/test.log	0000000000000004	00000000060e3793