New Go programmer here -- apologies if this is well worn territory, but my google searching hasn't turned up the answer I'm looking for.
Short Version: Can I, as a programmer external to the core Go project, force my packages to be imported with a specific name. If so, how?
Long Version: I recently tried to install the bcrypt package from the following GitHub repository, with the following go get
go get github.com/golang/crypto
The package downloaded correctly into my workspace, but when I tried to import it, I got the following error
$ go run main.go main.go:10:2: code in directory /path/to/go/src/github.com/golang/crypto/bcrypt expects import "golang.org/x/crypto/bcrypt"
i.e. something told Go this package was supposed to be imported with golang.org/x/crypto/bcrypt. This tipped me off that what I actually wanted was
go get golang.org/x/crypto/bcrypt
I'd like to do something similar in my own packages — is this functionality built into Go packaging? Or are the authors of crypto/bcrypt doing something at runtime to detect and reject invalid package import names?
Yes it's built in, I can't seem to find the implementation document (it's a relatively new feature in 1.5 or 1.6) however the syntax is:
package name // import "your-custom-path"
Example: https://github.com/golang/crypto/blob/master/bcrypt/bcrypt.go#L7
// edit
The design document for this feature is https://docs.google.com/document/d/1jVFkZTcYbNLaTxXD9OcGfn7vYv5hWtPx9--lTx1gPMs/edit
// edit
#JimB pointed out to https://golang.org/cmd/go/#hdr-Import_path_checking, and in the go1.4 release notes: https://golang.org/doc/go1.4#canonicalimports
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I am following a golang book (using go 1.15) which not surprisingly advocates using go modules for dependency management. I have no problem following along until a chapter where it says "because we have module enabled for our project, after adding a new import to our code, we can just do go run and go is clever enough to notice the new import and will auto download the package as well as update the go.mod file for us. We don't need to manually do go get". In book, it appears that this auto download does work as there is screenshot in the book showing the download message.
To clarify, this new import is added for the first time to the project.
This is totally new to me and got me excited but when I tried it, it doesn't work. It says no required module provides package github.com/xxx/yyy; to add it: go get github.com/xxx/yyy;
I obviously have module enabled for the project.
Is there any setting I missed to enable this auto download?
I am using go 1.16
When you create a new project, you must manually add the libraries that you will use via the command:
go get ...
But later, if you run that project in another machine, for example, once the go run command or the go build command, Go will download and add the libraries automatically.
For example, if you download a project from GitHub and run it, it will load and add all the libraries automatically.
All you have to do is type: go run ... or go build
Due to this problem it looks like for providers you have to get a current version of the SDK (2.4.4 at time of post). This post has a lot of info on how to import a specific version of a package but surely every single provider writer isn't manually pulling the most recent version of the SDK (or are they)?
I'm new to Go/Terraform so maybe I'm missing something obvious but the providers I've found (including the official example) have something like:
import(
"github.com/hashicorp/terraform-plugin-sdk/v2/diag"
"github.com/hashicorp/terraform-plugin-sdk/v2/helper/schema"
"github.com/hashicorp/terraform-plugin-sdk/v2/helper/validation"
)
The current version is not 2 - it is 2.4.4. Now I know those are local paths but what confuses me is when I run something like go get it goes and pulls those down for me. I tried doing:
"github.com/hashicorp/terraform-plugin-sdk/v2.4.4/helper/schema"
but go get very much doesn't like that. How is go get finding those package versions? Is there an import syntax that just gets me the latest build or allows me more granularity? I haven't found a good way to tell what version of the SDK I have after running go get but based on this error message:
it looks like I have 2.0 because that error is, as I understand it, fixed in newer versions of the SDK.
I figured it out. The behavior is controlled by the go.mod file.
In there you'll find:
require (
github.com/hashicorp/terraform-plugin-sdk v1.14.0 // indirect
github.com/hashicorp/terraform-plugin-sdk/v2 v2.0.1
As mentioned by #JimB the v2 is the major version for the plugin. v2.0.1 are GitHub tags. Changing this to v2.4.4 obtains the desired behavior.
There are three different etcd-go package, they are:
github.com/coreos/etcd
go.etcd.io/etcd
go.etcd.io/etcd/v3
According to the commit here, all the
official codes have changed the package from go.etcd.io/etcd to go.etcd.io/etcd/v3 with following messages:
This change makes the etcd package compatible with the existing Go
ecosystem for module versioning.
But I can't get the go.etcd.io/etcd/v3 package by go get command.
So what's the difference between these three etcd-go packages? And how to use them properly.
Thanks in advance.
There is a known issue in the client v3.4 with go get failing. See this issue: https://github.com/etcd-io/etcd/issues/11154
Although the issue has been closed because it is (supposedly) fixed in v3.5, that version is not yet released (when writing this).
There are a few workarounds posted the issue above. The one that worked for us was to circumvent the incorrectly implemented go module of etcd and pin the version to a commit directly in our go.mod file:
require go.etcd.io/etcd v0.0.0-20200520232829-54ba9589114f
The clientv3 is then imported with:
import "go.etcd.io/etcd/clientv3"
The document for no.2 in the question points to this link
https://pkg.go.dev/go.etcd.io/etcd/clientv3?tab=doc
The package has below version and commit hash
v0.5.0 (ae9734e)
The document for no.3 in the question points to this link
https://pkg.go.dev/go.etcd.io/etcd/v3/clientv3?tab=doc
The package has below version and commit hash
v3.3.0 (c20cc05)
etcd would have made a breaking change in latest release and hence changed the module path to differ from the old path. This is a convention recommended in official Golang blog.
Read this blog.
https://blog.golang.org/v2-go-modules
Even though both of them point to the same repo, you have to import these versions differently like below. You can find the correct module path from go.mod file in the root of the repository.
import "go.etcd.io/etcd/clientv3"
import "go.etcd.io/etcd/v3/clientv3"
Sorry, very much a newbie golang question. I have a github project named journalbeat that I am modifying.
When I clone that repository I can set the GOPATH and run go get to grab all the imports and it places them into src.
I have a new import I want to add.
import "github.com/danwakefield/fnmatch"
but it doesn't grab it. How does simply running go get determine whether something is downloaded or not?
And finally, the vendoring system is used. How do I populate that with the fnmatch? do I create it manually? it all seems very cumbersome.
I thought go get was meant to make all this easy?
Try instead a dependency manager: the most recent and actively developed one is golang/dep.
Reading dep "issue" 943, use:
dep ensure
That will set up vendored dependencies through import analysis, and you can configure locking those down if need be.
Try go get with the verbose flag -v like:
go get -v github.com/danwakefield/fnmatch
This will show you more details. Post the result here.
we use Glide package management tool for GO. Go check it out gitHub link
Hi I want to import a 3rd party library to GO playground, I saw an answer for this question: https://stackoverflow.com/a/27813778/6638204 but it said that this can not be done, but the xiam/go-playground library on github states that it can do this. I tried using it but I did not understand what should I exactly do. I successfully installed the library and used it to run programs that do not need third party libraries. but I did not get how can I import a third party library. ps: I have docker installed in my machine
The answer is still the same: you can't do that on the "official" Go Playground (at https://play.golang.org/).
If you or someone else runs a custom, modified version of the Go Playground: then the answer is you can do there whatever is allowed, which may include the usage of external libraries which the custom engine may go get prior to compilation and execution.
Also see related question: Which packages may be imported in the go playground?
You might be able to do it since May 14th, 2019
See this tweet (from Brad Fitzpatrick)!
The #golang playground now supports third-party imports, pulling them in via https://proxy.golang.org/
Example: https://play.golang.org/p/eqEo7mqdS9l 🎉
Multi-file support & few other things up next.
Report bugs at golang/go issue 31944, or here on the tweeters.
But that means you have published your package deliverable in such a way it is reference by the Go proxy.