如何找到 Go 模块源缓存？

Question

我已经将一个项目升级到 Go 1.11 并为我的项目启用了模块支持，但似乎 CircleCI 正在重新下载每个构建的依赖项。我知道 CircleCI 允许在重建之间进行缓存，所以我查看了 Go 模块的文档，虽然它提到了缓存，但我似乎无法找到它实际存在的位置。

Go 模块的源缓存在哪里？

Answer 1

从最终的 1.11 版本开始，go module cache（用于存储下载的模块和源代码）位于 $GOPATH/pkg/mod 位置（参见文档here)。为了澄清，go build cache（用于存储最近的编译结果）位于不同的位置。

This article, indicated that it's in the $GOPATH/src/mod, but in the timespan of the recent ~40 days, the golang team must have changed that target location. This message thread 讨论了为什么下载的项目最终在 $GOPATH/pkg。

您还可以使用 go mod download -json 命令查看下载的 modules/source 元数据及其在本地磁盘上的位置。下面的示例输出：

$ go mod download -json
go: finding github.com/aws/aws-sdk-go v1.14.5
go: finding github.com/aws/aws-lambda-go v1.2.0
{
    "Path": "github.com/aws/aws-lambda-go",
    "Version": "v1.2.0",
    "Info": "/go/pkg/mod/cache/download/github.com/aws/aws-lambda-go/@v/v1.2.0.info",
    "GoMod": "/go/pkg/mod/cache/download/github.com/aws/aws-lambda-go/@v/v1.2.0.mod",
    "Zip": "/go/pkg/mod/cache/download/github.com/aws/aws-lambda-go/@v/v1.2.0.zip",
    "Dir": "/go/pkg/mod/github.com/aws/aws-lambda-go@v1.2.0",
    "Sum": "h1:2f0pbAKMNNhvOkjI9BCrwoeIiduSTlYpD0iKEN1neuQ=",
    "GoModSum": "h1:zUsUQhAUjYzR8AuduJPCfhBuKWUaDbQiPOG+ouzmE1A="
}
{
    "Path": "github.com/aws/aws-sdk-go",
    "Version": "v1.14.5",
    "Info": "/go/pkg/mod/cache/download/github.com/aws/aws-sdk-go/@v/v1.14.5.info",
    "GoMod": "/go/pkg/mod/cache/download/github.com/aws/aws-sdk-go/@v/v1.14.5.mod",
    "Zip": "/go/pkg/mod/cache/download/github.com/aws/aws-sdk-go/@v/v1.14.5.zip",
    "Dir": "/go/pkg/mod/github.com/aws/aws-sdk-go@v1.14.5",
    "Sum": "h1:+l1m6QH6LypE2kL0p/G0Oh7ceCv+IVQ1h5UEBt2xjjU=",
    "GoModSum": "h1:ZRmQr0FajVIyZ4ZzBYKG5P3ZqPz9IHG41ZoMu1ADI3k="
}

该输出来自 CircleCI 2.0 的构建，使用他们的官方 circleci/golang:1.11 图像。这是一个人为的例子，展示了如何为新的 golang 模块缓存位置包含 restore_cache 和 save_cache 步骤：

steps:
    - checkout
    - restore_cache:
       keys:
         - gomod-cache-{{ checksum "go.sum" }}
    - run: go vet ./...
    - save_cache:
        key: gomod-cache-{{ checksum "go.sum" }}
        paths:
          - /go/pkg/mod

如何找到 Go 模块源缓存？

How do I find the Go module source cache?

go

circleci

go-modules