Will go get command update the package in my local machine - go

Suppose I download a package using go get <Import path of package>. Now after x number of days that package has been updated remotely and now if I run again go get <Import path of package> will it be updated on my local too?

The go get <Import path of package> command will not update the local copy if there is already a local copy installed.
The go get documentation says:
The -u flag instructs get to use the network to update the named packages and their dependencies. By default, get uses the network to check out missing packages but does not use it to look for updates to existing packages.
Run go get -u <Import path of package> to get or update the local copy.

No. According to the go get documentation it will not. If you want to update a local package you have to use the -u flag.
$ go help get
......
The -u flag instructs get to use the network to update the named packages
and their dependencies. By default, get uses the network to check out
missing packages but does not use it to look for updates to existing packages.
Things change a bit if you use Go modules. Then the go.mod file is consulted, but by default it won't fetch the latest version automatically unless you tell it too. For this new behaviour please take a deeper look at the official docs https://github.com/golang/go/wiki/Modules#daily-workflow.

Related

Is it possible to update local packages without running go install?

I am trying to import a local file into my main.go file and this tutorial (and other similar tutorials) says to run go install <path> in order to import that path as a package. This seems like a slow way to develop local packages because you would have to run go install <path> every time you want to see the changes in your local package.
Is there a faster way to import/update local packages? I am using gomon to auto-reload my code after updating it, so ideally, my code would auto-reload after updating a local package.
You should use go modules. The tutorial you mentioned appears to be older than the modules feature. In short: you can import a package, run go build, and any imported external package will automatically be downloaded for you as needed, no need to do a go get. Start here:
https://blog.golang.org/using-go-modules
https://github.com/golang/go/wiki/Modules

Get missing imports in batches

When I clone a project written in golang, it is normal that a lot of imports like
'github.com/XXXX' are missing. Is there any way to get these imports in batches by a command? or I am suppose to get them one by one.
You should use go get to get "remote" packages. Quoting from Command go: Download and install packages and dependencies
Get downloads the packages named by the import paths, along with their dependencies. It then installs the named packages, like 'go install'.
You may use the -v flag in all of the following commands, and so you will see what go get is doing under the hood.
You may use the -d flag if you just want to download the packages but you do not want to install them.
The examples use the example remote package github.com/somebody/somepackage, but obviously it works for other packages hosted outside of github.com.
For more information, see the official doc: Command go, or type go help get.
To get a single package with all the dependencies of that package and install them, use
go get github.com/somebody/somepackage
To get a package with all its dependencies, and all other packages rooted at that path (along with their dependencies), and install all of them, use:
go get github.com/somebody/somepackage/...
Quoting from Command go:
An import path is a pattern if it includes one or more "..." wildcards, each of which can match any string, including the empty string and strings containing slashes. Such a pattern expands to all package directories found in the GOPATH trees with names matching the patterns.
To get a package with all its dependencies (and "subpackages") including dependencies of tests, and install all of them, use:
go get -t github.com/somebody/somepackage/...
To update a package you already have, use:
go get -u github.com/somebody/somepackage/...
To fetch dependencies of a package you already have (which is not necessarily from a remote location):
go get path/to/package/name/...
Or go to its folder and then you may use a relative path:
go get ./...
A lot of golang projects now use dependency management so you should look for that first. e.g a Glide.lock (glide) or Gopkg.lock (dep - the way people are moving now) file present in the root of the project.
https://github.com/golang/dep
https://golang.github.io/dep
if dep is used and you have it installed then dep ensure will set the dependencies up for you and make sure you get the versions the author intended
if a project is not using dependency management you can just get the packages with go get ./... but I don't think you will be guaranteed the correct versions (e.g if the author was pinned to a version tag for a dep)
If you run dep init it sets up dep on a project and will attempt to resolve the correct versions, however this doesnt always work if the stars dont align (e.g I have seen issues with dependencies using gopkg.in)
try using go get ./... in root of your project

How do I rebuild native Golang packages after I modify them?

I modified the net package and I want to use the modified version in my application but it keeps using the old code.
This works:
$ go install -a net
It wasn't rebuilding for me either, but the -a forces a rebuild even if the toolchain thinks the specified package is up to date.
In case someone is using Docker:
My changes wasn't having effect because I was editing the package outside the container. Only the code of our project is mapped by a volume inside the container, but not the third party packages.
Once I edited the package code inside the container, I do not even had to run a go install -a ... like proposed by #elimisteve. It worked just by recompiling the project.

Composer - restore deleted file?

I use composer to manage packages. But I delete one of files from package (I use composer status -v to check this).
Is it possible to restore changed/deleted files to it base (installed) state via composer (composer install doing nothing in my case) ?
Thanks.
ps. It's look like there no way to restore separate file from repo, after his been changed/deleted. Of course, it's possible to delete entire vendor dir, and reinstall some package totally.
I edit dependant package source code all the time and run into the issue of my local being out of sync with the remove source.
When things get really sideways and nothing works: delete the package providers dir inside the ./vendor (exp: ./vendor/author-name). Then composer will see the package is missing when running composer install. It will re-download the version specified in composer.lock.
If you want the latest version of all the packages when re-installing; composer update is what you want.
I also recommend using -o -vvv to generate the AuoLoader file and provide verbose output.

can't load package: package .: no buildable Go source files

Here is the error message:
% go get
can't load package: package .: no buildable Go source files in /Users/7yan00
% echo $GOPATH
/Users/7yan00/Golang
How would you troubleshoot that error?
Make sure you are using that command in the Go project source folder (like /Users/7yan00/Golang/src/myProject).
One alternative (similar to this bug) is to use the -d option (see go get command)
go get -d
The -d flag instructs get to stop after downloading the packages; that is, it instructs get not to install the packages.
See if that helps in your case.
But more generally, as described in this thread:
go get is for package(s), not for repositories.
so if you want a specific package, say, go.text/encoding, then use
go get code.google.com/p/go.text/encoding
if you want all packages in that repository, use ... to signify that:
go get code.google.com/p/go.text/...
You should check the $GOPATH directory. If there is an empty directory of the package name, go get doesn't download the package from the repository.
For example, If I want to get the github.com/googollee/go-socket.io package from it's github repository, and there is already an empty directory github.com/googollee/go-socket.io in the $GOPATH, go get doesn't download the package and then complains that there is no buildable Go source file in the directory. Delete any empty directory first of all.
Another possible reason for the message:
can't load package: .... : no buildable Go source files
Is when the source files being compiled have:
// +build ignore
In which case the files are ignored and not buildable as requested.This behaviour is documented at https://golang.org/pkg/go/build/
To resolve this for my situation:
I had to specify a more specific sub-package to install.
Wrong:
go get github.com/garyburd/redigo
Correct:
go get github.com/garyburd/redigo/redis
If you want all packages in that repository, use ... to signify that, like:
go get code.google.com/p/go.text/...
you can try to download packages from mod
go get -v all
I had this exact error code and after checking my repository discovered that there were no go files but actually just more directories. So it was more of a red herring than an error for me.
I would recommend doing
go env
and making sure that everything is as it should be, check your environment variables in your OS and check to make sure your shell (bash or w/e ) isn't compromising it via something like a .bash_profile or .bashrc file. good luck.

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