无法在Haskell Stack项目中构建yesod / amazonka依赖项

Question

我正在尝试在使用同样出色的Web框架yesod构建的API的后端部分中使用优秀的AWS SDK amazonka ，但是我很难让这两个库的依赖项协同工作。

我开始使用scaffolded yesod项目

stack new my-project yesod-mongo

用最新版本的yesod（1.6.0）填充我的cabal文件。 amazonka-core将依赖性amazonka-core和amazonka-ssm （例如）添加到我的cabal文件中

Error: While constructing the build plan, the following exceptions were encountered:

In the dependencies for my-project-0.0.0:
    amazonka-core must match -any, but the stack configuration has no specified version
              (latest matching version is 1.5.0)
    amazonka-ssm must match -any, but the stack configuration has no specified version
             (latest matching version is 1.5.0)
needed since my-project is a build target.

正如所建议的那样，我尝试将amazonka-core-1.5.0和amazonka-ssm-1.5.0到extra-deps下的stack.yaml文件中，但这不起作用：

Warning: WARNING: /home/ubuntu/my-project/my-project.cabal was modified manually.
     Ignoring package.yaml in favor of cabal file. If you want to use package.yaml
     instead of the cabal file, then please delete the cabal file.

Error: While constructing the build plan, the following exceptions were encountered:

In the dependencies for amazonka-core-1.5.0:
    conduit-1.3.0.2 from stack configuration does not match >=1.1 && <1.3 (latest
                matching version is 1.2.13.1)
needed due to my-project-0.0.0 -> amazonka-core-1.5.0

经过一些挖掘后，看起来yesod模板构建的快照是lts-11.6，但是亚马逊卡库中包含的最新快照是lts-10.9。 所以，我尝试从yesod-mongo模板再次构建项目，但这次指定了一个较旧的快照：

ubuntu:~$ stack new my-project yesod-mongo --resolver lts-10.9
Downloading template "yesod-mongo" to create project "my-project" in my-project/ ...
Looking for .cabal or package.yaml files to use to init the project.
Using cabal packages:
- my-project/

Selected resolver: lts-10.9
Resolver 'lts-10.9' does not have all the packages to match your requirements.
    classy-prelude version 1.3.1 found
        - my-project requires ==1.4.*
    classy-prelude-conduit version 1.3.1 found
        - my-project requires ==1.4.*
    classy-prelude-yesod version 1.3.1 found
        - my-project requires ==1.4.*
    http-conduit version 2.2.4 found
        - my-project requires ==2.3.*
    persistent version 2.7.1 found
        - my-project requires ==2.8.*
    persistent-mongoDB version 2.6.0 found
        - my-project requires ==2.8.*
    yesod version 1.4.5 found
        - my-project requires ==1.6.*
    yesod-auth version 1.4.21 found
        - my-project requires ==1.6.*
    yesod-core version 1.4.37.3 found
        - my-project requires ==1.6.*
    yesod-form version 1.4.16 found
        - my-project requires ==1.6.*
    yesod-static version 1.5.3.1 found
        - my-project requires ==1.6.*
    Using package flags:
        - my-project: dev = False, library-only = False

现在我感到茫然而且有点沮丧。 似乎模板可能忽略了快照规范。 所以，我的问题：

有没有办法从使用特定快照填充cabal和stack.yaml文件的模板构建脚手架网站？ 我还能做些什么才能让它发挥作用吗？

如果它有用，很乐意提供更多信息。

编辑：我也尝试在上面的代码段中查看软件包的版本，虽然这解决了构建依赖项的问题，但现在脚手架网站没有编译（大概是因为事情已经从yesod-1.4以有意义的方式改变了。 5到yesod-1.6.0）。

Answer 1

不幸的是，到目前为止，您无法使用商业Haskell的堆栈模板与yesod和amazonka。 原因是：

• 版本1.3中最近有一个管道重写
• 最近的Yesod 1.6引入了一些重大变化，这取决于导管> = 1.3
• Amazonka不适用于最新版本的管道

让它工作的唯一方法是切换回旧版本的堆栈模板（那些实际上与stackage解析器10.9一起使用的模板），然后使用它来创建一个新项目。 幸运的是，Stack支持自定义堆栈模板：

$ stack new my-project https://raw.githubusercontent.com/github-user-id/stack-templates/master/my-template.hsfiles