Hello i am currently running into a problem with using Heroku! It finds all my dependency's until
build project: cannot load io/fs: cannot find module providing package io/fs
I have the vendor directory on my github repo but it just wont build?
On heroku -> your project -> Settings -> Buildpacks, and add 'heroku/go'.
Then execute in any terminal:
heroku config:set GOVERSION=1.16
Per #jimb, you're likely using an earlier than Go 1.16 version.
fs became available with Go 1.16:
https://pkg.go.dev/io/fs?tab=versions
Check
go version
And you go.mod Go version.
I have an application that loads plugins on startup (daemon). In a subpackage (daemon/interfaces), I have a few interfaces that plugins for this program should use.
This means that the main program also gets imported by the plugin.
I am using Go modules (for both the main program and the plugin) to fix the versions, and I can see in go.mod that it is using the latest version of the main program for the plugin.
I can build them both fine, but when I load the plugin it gives me an error saying
panic: plugin.Open("plugins/my-plugin"): plugin was built with a different version of package daemon/interfaces
I am using Go 1.12.7 to build both of the packages.
I fixed this by adding a replace statement to my plugin go.mod file
module github.com/user/plugin
go 1.12
require (
github.com/user/daemon v1.1.1
)
replace github.com/user/daemon v1.1.1 => ../local/path/to/daemon/
It also helps when you are building the project from outside of the directory where the source code is in by using the full name of the project (go build github.com/user/project/)
There is a related Github issue on the Golang repository that you can find here
Apparently, the issue is still open. The issue opener presented the workaround, which I was able to use. Please look at the history lines below for details.
git clone https://github.com/zimnx/central.git
git clone https://github.com/zimnx/plugins.git
cd central/
go clean -modcache
git checkout v1.0.0
go install -a
cd ../plugins/
rm go.mod
go mod init github.com/zimnx/plugins
echo '' >> go.mod
echo 'replace github.com/zimnx/central => ../central' >> go.mod
go build -buildmode=plugin -o plugin.so
central plugin.so
Works for me. Mistery still... :) The output has been saved for the most curious.
I've been trying to set up migrations for a golang application on Heroku. I'm using native Go modules (vgo) and the official Heroku build pack. For migrations I'm using the migrate package.
The thing is, I could run migrations when the main function runs, but it feels a bit hacky, this would mean that every time the app restarts it will run the migrations. I would prefer to just run the schema migration when deploying.
I'm not sure how this can be accomplished, when I log in to the instance the go binary is not installed, it's like the build pack only executes the main function.
I could live with doing it with a Heroku CLI command but I can't find how to do this in the docs nor via Google.
All of your dependencies should be defined such that Heroku can install them for you. For Go, Heroku supports godep and govendor. If you're not already using one, pick one and start.
Your dependency file should be committed to your repository. For godep that's Godeps/Godeps.json and for govendor it's vendor/vendor.json. Your dependencies themselves should not be committed.
After you've added a dependency on migrate it should be available on Heroku. You can run migrate up and other commands via heroku run bash. Once you're comfortable running migrations manually you might want to consider adding a release phase command to your Procfile so migrations get applied automatically when you deploy a new version.
I've recently started with Go 1.11 and love the modules. Apart from runtime dependencies I need to work with go modules during the build, e.g. during go generate.
How can I install a specific build dependency (e.g. github.com/aprice/embed/cmd/embed) and run that specific tool from which folder? Is go get the right tool for doing so?
If you get an error
I was not seeing the dependency that I wanted added to the go.mod and I was getting this error:
internal/tools/tools.go:6:5: import "github.com/UnnoTed/fileb0x" is a program, not an importable package
(fileb0x is the thing I'm trying to add)
I'm not 100% clear on the sequence of events that fixed it, but I did all of these things:
Using a "tools" package
I made a tools directory:
mkdir -p internal/tools
I put the tools package inside of it (as mentioned above):
internal/tools/tools.go:
// +build tools
package tools
import (
_ "github.com/UnnoTed/fileb0x"
)
Note that the tag is mostly not important. You could use foo:
// +build foo
However, you cannot use ignore. That's a special predefined tag.
// +build ignore
// NO NO NO NO NO
// `ignore` is a special keyword which (surprise) will cause
// the file to be ignore, even for dependencies
Updating go.mod
The best way is probably to run go mod tidy:
go mod tidy
However, before I did that I ran a number of commands trying to figure out which one would cause it to go into go.mod:
go install github.com/UnnoTed/fileb0x # didn't seem to do the trick
go get
go generate ./...
go build ./...
go install ./...
go mod vendor
Later I did a git reset and rm -rf ~/go/pkg/mod; mkdir ~/go/pkg/mod and found that go mod tidy did well enough on its own.
vendoring
In order to actually take advantage of the modules cache in a project you need to copy-in the source code
go mod vendor
That will grab all dependencies from go.mod
You also need to change nearly all of your go commands to use -mod=vendor in any Makefiles, Dockerfiles or other scripts.
go fmt -mod=vendor ./... # has a bug slated to be fixed in go1.15
go generate -mod=vendor ./...
go build -mod=vendor ./...
That includes go build, go get, go install, and any go run called by go generate (and even the go generate itself)
//go:generate go run -mod=vendor github.com/UnnoTed/fileb0x b0x.toml
package main
// ...
https://github.com/golang/go/issues/25922 proved helpful for me, especially
when using build-only dependencies with modules the main point is version selection (not installing these!)
To avoid installing you can modify your //go:generate directive to something like:
//go:generate go run golang.org/x/tools/cmd/stringer ARGS
There is also the best practices repo: https://github.com/go-modules-by-example/index/blob/master/010_tools/README.md
The convention is to add a file named "tools.go" that is guarded by a build constraint and imports all required tools:
// +build tools
package tools
import (
_ "github.com/aprice/embed/cmd/embed"
)
https://github.com/golang/go/issues/25922#issuecomment-412992431
The tools are then installed as usual in one of
$GOBIN
$GOPATH/bin
$HOME/go/bin
You may also want to follow https://github.com/golang/go/issues/27653, which discusses future explicit support for tools.
tools.go is a great solution if you're building an app or service. But if you're building a library, tools.go still leaks dependencies to things consuming your library (your tools are still there as indirect dependencies, and go mod tidy will pull them in since it considers every possible target). That's not the end of the world since those modules never end up in the actual built binaries of the consumer, but it's still messy.
https://github.com/myitcv/gobin/issues/44 is probably the most promising approach to fixing this long term, but short term I've used a combination of the "internal module" approach explained there along with https://github.com/izumin5210/gex.
First, I install gex globally:
GO111MODULE=off go get github.com/izumin5210/gex/cmd/gex
Then before actually using gex I create a structure like this:
myproject/
\
- go.mod: module github.com/ysamlan/myproject
\
internal/
\
tools/
- go.mod: module github.com/ysamlan/myproject/tools
To install a build-only tool I just cd internal/tools and run gex --add (sometool), which puts that tool in internal/tools/bin. CI scripts and other folks that want to build my stuff locally just need to run cd internal/tools && gex --build to reliably and reproducibly populate the tool binaries, but the top-level go.mod is unchanged.
The key piece there is creating that internal/tools/go.mod file with a different module path than the one the root project uses, and then only running gex from that directory.
coming from a Node environment I used to install a specific version of a vendor lib into the project folder (node_modules) by telling npm to install that version of that lib from the package.json or even directly from the console, like so:
$ npm install express#4.0.0
Then I used to import that version of that package in my project just with:
var express = require('express');
Now, I want to do the same thing with go. How can I do that?
Is it possible to install a specific version of a package? If so, using a centralized $GOPATH, how can I import one version instead of another?
I would do something like this:
$ go get github.com/wilk/uuid#0.0.1
$ go get github.com/wilk/uuid#0.0.2
But then, how can I make a difference during the import?
Go 1.11 will have a feature called go modules and you can simply add a dependency with a version. Follow these steps:
go mod init .
go mod edit -require github.com/wilk/uuid#0.0.1
go get -v -t ./...
go build
go install
Here's more info on that topic - https://github.com/golang/go/wiki/Modules
Really surprised nobody has mentioned gopkg.in.
gopkg.in is a service that provides a wrapper (redirect) that lets you express versions as repo urls, without actually creating repos. E.g. gopkg.in/yaml.v1 vs gopkg.in/yaml.v2, even though they both live at https://github.com/go-yaml/yaml
gopkg.in/yaml.v1 redirects to https://github.com/go-yaml/yaml/tree/v1
gopkg.in/yaml.v2 redirects to https://github.com/go-yaml/yaml/tree/v2
This isn't perfect if the author is not following proper versioning practices (by incrementing the version number when breaking backwards compatibility), but it does work with branches and tags.
A little cheat sheet on module queries.
To check all existing versions: e.g. go list -m -versions github.com/gorilla/mux
Specific version #v1.2.8
Specific commit #c783230
Specific branch #master
Version prefix #v2
Comparison #>=2.1.5
Latest #latest
E.g. go get github.com/gorilla/mux#v1.7.4
You can use git checkout to get an specific version and build your program using this version.
Example:
export GOPATH=~/
go get github.com/whateveruser/whateverrepo
cd ~/src/github.com/whateveruser/whateverrepo
git tag -l
# supose tag v0.0.2 is correct version
git checkout tags/v0.0.2
go run whateverpackage/main.go
Glide is a really elegant package management for Go especially if you come from Node's npm or Rust's cargo.
It behaves closely to Godep's new vendor feature in 1.6 but is way more easier. Your dependencies and versions are "locked" inside your projectdir/vendor directory without relying on GOPATH.
Install with brew (OS X)
$ brew install glide
Init the glide.yaml file (akin to package.json). This also grabs the existing imported packages in your project from GOPATH and copy then to the project's vendor/ directory.
$ glide init
Get new packages
$ glide get vcs/namespace/package
Update and lock the packages' versions. This creates glide.lock file in your project directory to lock the versions.
$ glide up
I tried glide and been happily using it for my current project.
Nowadays you can just use go get for it. You can fetch your dependency by the version tag, branch or even the commit.
go get github.com/someone/some_module#master
go get github.com/someone/some_module#v1.1.0
go get github.com/someone/some_module#commit_hash
more details here - How to point Go module dependency in go.mod to a latest commit in a repo?
Go get will also install the binary, like it says in the documentation -
Get downloads the packages named by the import paths, along with their dependencies. It then installs the named packages, like 'go install'.
(from https://golang.org/cmd/go/)
Update 18-11-23: From Go 1.11 mod is official experiment. Please see #krish answer.
Update 19-01-01: From Go 1.12 mod is still official experiment.
Starting in Go 1.13, module mode will be the default for all development.
Update 19-10-17: From Go 1.13 mod is official package manager.
https://blog.golang.org/using-go-modules
Old answer:
You can set version by offical dep
dep ensure --add github.com/gorilla/websocket#1.2.0
From Go 1.5 there's the "vendor experiment" that helps you manage dependencies. As of Go 1.6 this is no longer an experiment. Theres also some other options on the Go wiki..
Edit: as mentioned in this answer gopkg.in is a good option for pinning github-depdencies pre-1.5.
dep is the official experiment for dependency management for Go language. It requires Go 1.8 or newer to compile.
To start managing dependencies using dep, run the following command from your project's root directory:
dep init
After execution two files will be generated: Gopkg.toml ("manifest"), Gopkg.lock and necessary packages will be downloaded into vendor directory.
Let's assume that you have the project which uses github.com/gorilla/websocket package. dep will generate following files:
Gopkg.toml
# Gopkg.toml example
#
# Refer to https://github.com/golang/dep/blob/master/docs/Gopkg.toml.md
# for detailed Gopkg.toml documentation.
#
# required = ["github.com/user/thing/cmd/thing"]
# ignored = ["github.com/user/project/pkgX", "bitbucket.org/user/project/pkgA/pkgY"]
#
# [[constraint]]
# name = "github.com/user/project"
# version = "1.0.0"
#
# [[constraint]]
# name = "github.com/user/project2"
# branch = "dev"
# source = "github.com/myfork/project2"
#
# [[override]]
# name = "github.com/x/y"
# version = "2.4.0"
[[constraint]]
name = "github.com/gorilla/websocket"
version = "1.2.0"
Gopkg.lock
# This file is autogenerated, do not edit; changes may be undone by the next 'dep ensure'.
[[projects]]
name = "github.com/gorilla/websocket"
packages = ["."]
revision = "ea4d1f681babbce9545c9c5f3d5194a789c89f5b"
version = "v1.2.0"
[solve-meta]
analyzer-name = "dep"
analyzer-version = 1
inputs-digest = "941e8dbe52e16e8a7dff4068b7ba53ae69a5748b29fbf2bcb5df3a063ac52261"
solver-name = "gps-cdcl"
solver-version = 1
There are commands which help you to update/delete/etc packages, please find more info on official github repo of dep (dependency management tool for Go).
go get is the Go package manager. It works in a completely decentralized way and how package discovery still possible without a central package hosting repository.
Besides locating and downloading packages, the other big role of a package manager is handling multiple versions of the same package. Go takes the most minimal and pragmatic approach of any package manager. There is no such thing as multiple versions of a Go package.
go get always pulls from the HEAD of the default branch in the repository. Always. This has two important implications:
As a package author, you must adhere to the stable HEAD philosophy. Your default branch must always be the stable, released version of your package. You must do work in feature branches and only merge when ready to release.
New major versions of your package must have their own repository. Put simply, each major version of your package (following semantic versioning) would have its own repository and thus its own import path.
e.g. github.com/jpoehls/gophermail-v1 and github.com/jpoehls/gophermail-v2.
As someone building an application in Go, the above philosophy really doesn't have a downside. Every import path is a stable API. There are no version numbers to worry about. Awesome!
For more details : http://zduck.com/2014/go-and-package-versioning/
The approach I've found workable is git's submodule system. Using that you can submodule in a given version of the code and upgrading/downgrading is explicit and recorded - never haphazard.
The folder structure I've taken with this is:
+ myproject
++ src
+++ myproject
+++ github.com
++++ submoduled_project of some kind.
That worked for me
GO111MODULE=on go get -u github.com/segmentio/aws-okta#v0.22.1
There's a go edit -replace command to append a specific commit (even from another forked repository) on top of the current version of a package.
What's cool about this option, is that you don't need to know the exact pseudo version beforehand, just the commit hash id.
For example, I'm using the stable version of package "github.com/onsi/ginkgo v1.8.0".
Now I want - without modifying this line of required package in go.mod - to append a patch from my fork, on top of the ginkgo version:
$ GO111MODULE="on" go mod edit -replace=github.com/onsi/ginkgo=github.com/manosnoam/ginkgo#d6423c2
After the first time you build or test your module, GO will try to pull the new version, and then generate the "replace" line with the correct pseudo version. For example in my case, it will add on the bottom of go.mod:
replace github.com/onsi/ginkgo => github.com/manosnoam/ginkgo v0.0.0-20190902135631-1995eead7451
It might be useful.
Just type this into your command prompt while cd your/package/src/
go get github.com/go-gl/mathgl#v1.0.0
You get specific revision of package in question right into your source code, ready to use in import statement.
The current way to do this is to use go install
https://golang.org/doc/go-get-install-deprecation
Starting in Go 1.17, installing executables with go get is deprecated. go install may be used instead.
go install github.com/someone/some_module
Specific version
go install github.com/someone/some_module#v1.1.0
Specific commit
go install github.com/someone/some_module#commit_hash