89 lines
1.9 KiB
Go
89 lines
1.9 KiB
Go
// For more tutorials: https://blog.learngoprogramming.com
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//
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// Copyright © 2018 Inanc Gumus
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// Learn Go Programming Course
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// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
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//
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package main
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import (
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"fmt"
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"strconv"
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"strings"
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)
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// result stores the parsed result for a domain
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type result struct {
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domain string
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visits int
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// add more metrics if needed
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}
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// parser keep tracks of the parsing
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type parser struct {
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sum map[string]result // metrics per domain
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domains []string // unique domain names
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total int // total visits for all domains
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lines int // number of parsed lines (for the error messages)
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lerr error // the last error occurred
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}
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// newParser constructs, initializes and returns a new parser
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func newParser() *parser {
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return &parser{sum: make(map[string]result)}
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}
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// parse parses a log line and returns the parsed result with an error
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func parse(p *parser, line string) (parsed result) {
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if p.lerr != nil {
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return
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}
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p.lines++
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fields := strings.Fields(line)
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if len(fields) != 2 {
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p.lerr = fmt.Errorf("wrong input: %v (line #%d)", fields, p.lines)
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return
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}
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parsed.domain = fields[0]
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var err error
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parsed.visits, err = strconv.Atoi(fields[1])
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if parsed.visits < 0 || err != nil {
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p.lerr = fmt.Errorf("wrong input: %q (line #%d)", fields[1], p.lines)
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}
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return
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}
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// update updates the errors for the given parsing result
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func update(p *parser, parsed result) {
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if p.lerr != nil {
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return
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}
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domain, visits := parsed.domain, parsed.visits
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// Collect the unique domains
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if _, ok := p.sum[domain]; !ok {
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p.domains = append(p.domains, domain)
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}
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// Keep track of total and per domain visits
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p.total += visits
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// create and assign a new copy of `visit`
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p.sum[domain] = result{
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domain: domain,
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visits: visits + p.sum[domain].visits,
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}
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}
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// err returns the last error encountered
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func err(p *parser) error {
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return p.lerr
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}
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