MavenやGradleの依存ライブラリ解決にかかる時間を少し短縮できるかもしれない

development java

目的

  • 未公開記事の発掘
  • ニッチな話題だった

2015年からGCSにMaven Centralのコピーを公開するようになったそうです。知らなかった。

どれくらい違いが出るのか検証してみる。

検証

対象のホストは以下。

  • Maven Central(repo.apache.maven.org)
    • Maven Central の公式ホスト
  • GCS-Asia(maven-central-asia.storage-download.googleapis.com)
    • GCS の Asia 地域向けホスト
  • GCS-EU(maven-central-eu.storage-download.googleapis.com)
    • GCS の EU 地域向けホスト
  • GCS-US(maven-central.storage-download.googleapis.com)
    • GCS の US 地域向けホスト

計測は curl で行う。それぞれのホストに対して5回。

$ for m in repo.apache.maven.org maven-central-asia.storage-download.googleapis.com maven-central-eu.storage-download.googleapis.com maven-central.storage-download.googleapis.com; do
for i in {0..5}; do
curl -s -k -w "${m},${i},%{time_namelookup},%{time_connect},%{time_appconnect},%{time_pretransfer},%{time_redirect},%{time_starttransfer},%{time_total}\n" -o /dev/null https://${m}/maven2/org/springframework/spring-core/5.3.8/spring-core-5.3.8.jar;
done
done
repo.apache.maven.org,0,0.037991,0.163917,0.422735,0.422971,0.000000,0.546282,0.546399
repo.apache.maven.org,1,0.004278,0.121880,0.364024,0.364144,0.000000,0.481385,0.481420
repo.apache.maven.org,2,0.001639,0.119328,0.361785,0.361857,0.000000,0.486429,0.486477
repo.apache.maven.org,3,0.002099,0.124872,0.380066,0.380149,0.000000,0.507271,0.507390
repo.apache.maven.org,4,0.001770,0.125946,0.380944,0.381223,0.000000,0.506575,0.506630
repo.apache.maven.org,5,0.001851,0.124397,0.376576,0.376872,0.000000,0.502826,0.502898
maven-central-asia.storage-download.googleapis.com,0,0.001884,0.009613,0.055196,0.055288,0.000000,0.068453,0.224391
maven-central-asia.storage-download.googleapis.com,1,0.002481,0.013766,0.068994,0.069050,0.000000,0.088661,0.270275
maven-central-asia.storage-download.googleapis.com,2,0.003084,0.012668,0.063887,0.064081,0.000000,0.072885,0.235593
maven-central-asia.storage-download.googleapis.com,3,0.001820,0.009232,0.054758,0.054809,0.000000,0.062724,0.227797
maven-central-asia.storage-download.googleapis.com,4,0.004236,0.021772,0.079667,0.079779,0.000000,0.092243,0.263077
maven-central-asia.storage-download.googleapis.com,5,0.002611,0.044696,0.101837,0.101898,0.000000,0.118384,0.305925
maven-central-eu.storage-download.googleapis.com,0,0.001900,0.011311,0.066934,0.067014,0.000000,0.082776,0.257083
maven-central-eu.storage-download.googleapis.com,1,0.001837,0.023069,0.078694,0.078742,0.000000,0.096553,0.287659
maven-central-eu.storage-download.googleapis.com,2,0.002092,0.018734,0.327978,0.328036,0.000000,0.345902,0.521407
maven-central-eu.storage-download.googleapis.com,3,0.002118,0.019215,0.070883,0.071256,0.000000,0.083224,0.271967
maven-central-eu.storage-download.googleapis.com,4,0.004461,0.018585,0.074322,0.074431,0.000000,0.088315,0.252058
maven-central-eu.storage-download.googleapis.com,5,0.001913,0.015818,0.065436,0.065493,0.000000,0.076168,0.245924
maven-central.storage-download.googleapis.com,0,0.002025,0.016342,0.068950,0.069062,0.000000,0.082023,0.293154
maven-central.storage-download.googleapis.com,1,0.001882,0.017747,0.074114,0.074177,0.000000,0.085885,0.264096
maven-central.storage-download.googleapis.com,2,0.002242,0.016268,0.071127,0.071346,0.000000,0.086131,0.259000
maven-central.storage-download.googleapis.com,3,0.002341,0.016438,0.069612,0.069663,0.000000,0.085434,0.279309
maven-central.storage-download.googleapis.com,4,0.014452,0.028634,0.077995,0.078046,0.000000,0.088248,0.257237
maven-central.storage-download.googleapis.com,5,0.002168,0.016135,0.066451,0.066529,0.000000,0.077767,0.278174

集計結果。値の単位は秒で、5回の単純平均。最小値に(*)を付けてみた。

Maven Central は fastly を使ってても速さが出てないようだ。キャッシュが効いてるのかどうかはわからない。 合計時間のオーダーはあまり変わらない（250msと500ms）から、データ転送は速そう。

ホスト GCS-US GCS-Asia GCS-EU Maven Central
time_namelookup 0.004185 0.002686(*) 0.002386 0.008271
time_connect 0.018594 0.018624 0.017788(*) 0.130056
time_appconnect 0.071374 0.070723(*) 0.114041 0.381021
time_pretransfer 0.071470 0.070817(*) 0.114162 0.381202
time_starttransfer 0.084248 0.083891(*) 0.128823 0.505128
time_redirect 0 0 0 0
time_total 0.271828 0.254509(*) 0.306016 0.505202

設定の仕方

Maven

${HOME}/.m2/settings.xmlあるいは%USERPROFILE%\.m2\settings.xmlへ次のように記述する。

つまり、 settings 要素の子要素を追加すればよい。

<settings>
    <!-- 何かしらの設定 -->
    <mirrors>
        <mirror>
            <id>google-maven-central</id>
            <name>GCS Maven Central mirror Asia Pacific</name>
            <url>https://maven-central-asia.storage-download.googleapis.com/maven2/</url>
            <mirrorOf>central</mirrorOf>
        </mirror>
    </mirrors>
    <!-- 何かしらの設定 -->
</settings>

Gradle

${HOME}/.gradle/init.gradleあるいは%USERPROFILE%\.gradle\init.gradleを作成して次のように記述する。

allprojects {
    buildscript {
        repositories {
            mavenLocal()
            maven { url "https://maven-central-asia.storage-download.googleapis.com/maven2/" }
        }
    }

    repositories {
        mavenLocal()
        maven { url "https://maven-central-asia.storage-download.googleapis.com/maven2/" }
    }
}