衆所周知 Go Module 服務器被牆了，因此需要指定代理服務器或者全局 VPN，而代理服務器比較簡單方便，如：GOPROXYCN 和 GOPROXYIO。
而筆者之前很長一段時間利用 Hugo Module 來安裝和更新主題，速度十分緩慢，而且經常失敗，即使我設置了 GO_PROXY 環境變量。
錯誤日誌
1hugo: downloading modules …
2go: github.com/razonyang/hugo-theme-bootstrap@v1.0.0-alpha.1.0.20220708160018-560a68166b0a: invalid version: git fetch -f origin refs/heads/*:refs/heads/* refs/tags/*:refs/tags/* in /home/razonyang/Projects/razonyang/hugo-theme-bootstrap-site/vendor/modules/filecache/modules/pkg/mod/cache/vcs/348a35abd6584f23aeb4a9124871cf51b665ede955a2f430e06713f21b056184: exit status 128:
3 fatal: the remote end hung up unexpectedly
4 fatal: early EOF
5 fatal: index-pack failed
6hugo: collected modules in 1140149 ms
7WARN 2022/07/09 16:43:05 failed to download modules: failed to execute 'go [mod download]': failed to execute binary "go" with args [mod download]: go: github.com/razonyang/hugo-theme-bootstrap@v1.0.0-alpha.1.0.20220708160018-560a68166b0a: invalid version: git fetch -f origin refs/heads/*:refs/heads/* refs/tags/*:refs/tags/* in /home/razonyang/Projects/razonyang/hugo-theme-bootstrap-site/vendor/modules/filecache/modules/pkg/mod/cache/vcs/348a35abd6584f23aeb4a9124871cf51b665ede955a2f430e06713f21b056184: exit status 128:
8 fatal: the remote end hung up unexpectedly
9 fatal: early EOF
10 fatal: index-pack failed
11 *errors.errorString
12go: github.com/razonyang/hugo-theme-bootstrap@v1.0.0-alpha.1.0.20220708160018-560a68166b0a: invalid version: git fetch -f origin refs/heads/*:refs/heads/* refs/tags/*:refs/tags/* in /home/razonyang/Projects/razonyang/hugo-theme-bootstrap-site/vendor/modules/filecache/modules/pkg/mod/cache/vcs/348a35abd6584f23aeb4a9124871cf51b665ede955a2f430e06713f21b056184: exit status 128:
13 fatal: unable to access 'https://github.com/razonyang/hugo-theme-bootstrap/': GnuTLS recv error (-110): The TLS connection was non-properly terminated.
14Error: failed to get ["-d" "github.com/razonyang/hugo-theme-bootstrap@master"]: failed to execute 'go [get -d github.com/razonyang/hugo-theme-bootstrap@master]': failed to execute binary "go" with args [get -d github.com/razonyang/hugo-theme-bootstrap@master]: go: github.com/razonyang/hugo-theme-bootstrap@v1.0.0-alpha.1.0.20220708160018-560a68166b0a: invalid version: git fetch -f origin refs/heads/*:refs/heads/* refs/tags/*:refs/tags/* in /home/razonyang/Projects/razonyang/hugo-theme-bootstrap-site/vendor/modules/filecache/modules/pkg/mod/cache/vcs/348a35abd6584f23aeb4a9124871cf51b665ede955a2f430e06713f21b056184: exit status 128:
15 fatal: unable to access 'https://github.com/razonyang/hugo-theme-bootstrap/': GnuTLS recv error (-110): The TLS connection was non-properly terminated.
16 *errors.errorString
解決方法
後來搜索了下才知道，Hugo 遵循 HUGO_MODULE_PROXY 環境變量，而非 GOPROXY，除此之外還可以在配置文件中指定代理服務器：
config.toml
1[module]
2 proxy = 'https://goproxy.cn'
config.yaml
1module:
2 proxy: https://goproxy.cn
config.json
1{
2 "module": {
3 "proxy": "https://goproxy.cn"
4 }
5}
至於之前爲甚麼更新時而成功時而失敗，也許是因爲開了全局 VPN。