How to use an alternate go.mod file for local development? - go

Currently I am working on an API which uses Serverless Framework with Go.
I'm using the Serverless-offline plugin for local testing.
This API depends on a few other repositories (which I also maintain), which I import using the go.mod file.
However I am having a hard time refining my developer workflow.
Currently, if I want to make changes in a repository which this API depends upon, I have to alter the projects go.mod to include replace directives for the purpose of testing, but then I'm having to manually change it back for deployment to production.
Basically I'm looking for a way to include replace directives, which only get applied during local development. How has everyone else dealt with this problem?
Bonus question: Is there any way to run Serverless offline in docker? I'm finding that serverless-offline running on the bare metal is causing inconsistencies between different developers environments.

You can run go commands with an alternate go.mod file with the -modfile option:
From Build commands:
The -modfile=file.mod flag instructs the go command to read (and
possibly write) an alternate file instead of go.mod in the module root
directory. The file’s name must end with .mod. A file named go.mod
must still be present in order to determine the module root directory,
but it is not accessed. When -modfile is specified, an alternate
go.sum file is also used: its path is derived from the -modfile flag
by trimming the .mod extension and appending .sum.
Create a local.go.mod file with the necessary replace directive for development and build, for example, with:
go build -modfile=local.go.mod ./...

Related

Is it possible to turn off a go workspace without deleting the go.work file?

I must be missing something here. It seems like the point of go workspaces is to enable local dev without mucking up the go.mod file with "replace", which seems great. But if a go.work file exists, any go command will silently use the local dev related dependencies defined in that file. The default GOWORK env var cannot be edited, so the existence of the file is enough to quietly use different dependencies than the go.mod file for any commands run. This seems like a massive footgun to release local dev changes as part of your package if anyone forgets to run all commands with GOWORK=off or delete the go.work file. Why would running in dev mode be the default? Is there a way to turn it off without deleting the file?

VS Code showing me "Error loading workspace: found module "main.go" twice in the workspace"

I am using the primary GO extension.
I use VS code a lot, now I'm learning GO lang.
And when I open VS Code every time I'm getting this:
Error loading workspace: found module "main.go" twice in the workspace.
While running the code it's giving the right output.
I don't know how to fix this.
Anybody, help me with this error.
It would be better to open in VSCode only one folder with its own go.mod project.
A workspace with multiple go.mod/project should be supported with 1.18
The go command now supports a "Workspace" mode.
If a go.work file is found in the working directory or a parent directory, or one is specified using the -workfile flag, it will put the go command into workspace mode.
In workspace mode, the go.work file will be used to determine the set of main modules used as the roots for module resolution, instead of using the normally-found go.mod file to specify the single main module.
As described in "How to make VScode Go work in a Multi-Module Repo" from Varun Kumar, this used to work:
If you want to work with all the nested modules in a single workspace, there is an opt-in module feature that allows to work with multiple modules without creating workspace folders for each module. Set this in your settings -
"build.experimentalWorkspaceModule": true
But as per september 2022 is deprecated.
See more at gopls documentation "Setting up your workspace".

Is there a way to have required modules on local machine rather than to get them online

I work in a closed environment in which machines do not have access to internet. I'm wondering if there is a way for me to load the dependency modules for development with Go. One way I am thinking is to get the package files, if there is any. However, I couldn't find any such file for the dependencies I am using.
There are several things you could do:
You can use replace directives in your go.mod file to redirect packages to local directories where you have copies of the dependency packages.
You can use go mod vendor (see docs) to "vendor" dependency packages locally.
You can use a local proxy and set the GOPROXY env var.

How can I use a local repository in the vendor in Google Cloud Functions with Go

I'm trying to deploy a Google Cloud Function written in Go.
By doing some research I found out that vendor files are prefered over go.mod so I'm vendoring everything I use (which includes some local dependencies) and ignoring the go.mod/sum files in the .gcloudignore file.
The problem is that after trying to deploy, I get the following error:
go: nimbus#v0.0.0-00010101000000-000000000000: parsing /nimbus/go.mod: open /nimbus/go.mod: no such file or directory; Error ID: 03a1e2f7
nimbus is my local dependency and it has the following structure:
My Function repository has the following structrure:
and my go.mod file is:
module my_function
go 1.13
require nimbus v0.0.0-00010101000000-000000000000
replace nimbus => ../../../nimbus
I've tried this solution https://stackoverflow.com/questions/5441096 already. But it did not fix my issue.
I've tried everything to solve this issue, but nothing seems to work.
If you have a go.mod file and a vendor directory, the vendor directory will be ignored when you deploy your function.
https://cloud.google.com/functions/docs/writing/specifying-dependencies-go
I have used modules when deploying GCP functions in Go. Haven't had any problems. But I can't speak to the preference of using vendor/ instead. It should work, just without the go.mod file.
Turns out the problem was very complicated and I hope Google finds a solution for it asp.
By deploying my function using Cloud Build, It would read from my repository on Google Source, but, by reading from there it would bypass the .gcloudignore file and deploy both the go.mod/sum files and the vendor directory with my local code.
As said in https://stackoverflow.com/a/62050872/10316247:
If you have a go.mod file and a vendor directory, the vendor directory will be ignored when you deploy your function.
So the error would occur because of my go.mod not being able to find local repository.
My solution was to rename my go.mod/sum files so it would not be considered:
When you use golang 1.16 and specify golang 1.16 in the go.mod folder it will instead default to using the vendor files with the --mod=vendor flag set, which will solve this issue.
You'll just need to ensure your module name is formatted correctly (something like example.com/module).

How to use modules replace functionality in cloud functions

I have a google cloud function that is a subdirectory in a repository. It uses the "Directory with source code" option in the settings menu. I keep getting this error on deploy:
Deployment failure:
Build failed: go: parsing /utils/pubsub/go.mod: open /utils/pubsub/go.mod: no such file or directory
go: error loading module requirements
I'm assuming that GCF does not upload the entire directory to the instance, but instead only the folder? This breaks the replace functionality of Go modules. Is there something I am doing wrong?
Link to the repo: https://github.com/FreekingDean/jeffbotgo/tree/5d735cc/slackevent
I work at Google and on this product.
Only the directory where you run gcloud is uploaded. There is no staging step beyond zipping the current directory and uploading it.
Notably, modules are preferred by the builder over vendor. If there is a go.mod, modules will be used. When you upload your function, it only includes the directory with your function at the root, not any directories one level up. So, when there is a go.mod and you have a replace directive pointing one level up, it will not work.
The solution for now with this layout is to vendor and not upload the go.mod/go.sum files. When using gcloud, you can create a .gcloudignore file to do this for you. See https://cloud.google.com/functions/docs/concepts/go-runtime#specifying_dependencies for more detail. Alternatively, modify your project to include any necessary helper packages in subdirectories.
I had the same issue today.
When reading thru the documentation for the 8th time i came across a warning box bellow the "Vendor directory" headline.
Warning: If your project has both a go.mod file and a vendor directory
at the root of your project, the vendor directory will be ignored
during deployment. You must use a .gcloudignore file to ignore the
go.mod file in order to ensure that your vendor directory is used
during deployment.
So basically once i added a .gcloudignore file with go.mod (will add go.sum as well) everything worked. So i guess if you have a go.mod file the cloud function will try to fetch dependencies instead of using the ones uploaded in the vendor folder.
I'm just guessing here tough.

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