In an iOS c++/Qt application, I need to ship a few files and to keep them in their directory structure.
For the Android version, we bundle a zip which we unzip on the target before creating the QApplication.
On iOS, it seems that CMake is not capable of bundling files in a tree:
https://cmake.org/cmake/help/latest/prop_tgt/RESOURCE.html#prop_tgt:RESOURCE
https://cmake.org/cmake/help/latest/prop_sf/MACOSX_PACKAGE_LOCATION.html
I am not sure if this is a limitation of cmake or if this is a global limitation on iOS.
From the docs about iOS bundles:
It uses a relatively flat structure with few extraneous directories in an effort to save disk space and simplify access to the files.
What would be the preferred approach?
Is there a solution to ship the files from CMake directly?
If not, how can I achieve this so that they are available before the QApplication is created?
The xcode command
Thanks to #Cy-4AH, I added the folder in Xcode and could get the command to do this:
CpResource _PATH_TO_DIRECTORY_ _APP_BUNDLE_DIRECTORY_/_RESOURCE_DIR_NAME_
cd /Users/denis/opt/qfield/ios/QField
export PATH="....."
builtin-copy -exclude .DS_Store -exclude CVS -exclude .svn -exclude .git -exclude .hg -strip-debug-symbols -strip-tool /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/strip -resolve-src-symlinks _PATH_TO_DIRECTORY_ _APP_BUNDLE_DIRECTORY_
But how can I create this from cmake? builtin-copyis an xcode command.
Simple system copy command
From an old (2008) discussion, we could use simple cp commands.
This works up to signing, but then I get an error unsealed contents present in the bundle root.
From this answer, it seems related that I cannot simply add folders in the resource directory. From the docs anatomy of framework bundles: Nonlocalized resources reside at the top level of the Resources directory
(Disclaimer: I'm not a CMake user, and there may be a more CMake-ey way to do this)
If you can set up post-build action, the following terminal script can efficiently sync files into your bundle from another location. I use it in my game engine because it only copies updated or new files upon subsequent builds, and preserves directory structure:
mkdir -p PATHTO/ORIGINFOLDERNAME
mkdir -p PATHTOBUILDFOLDER/PROJECTNAME.app/Contents/Resources/DESTINATIONFOLDERNAME
rsync -avu --delete --exclude=".*" PATHTO/ORIGINFOLDERNAME/ PATHTOBUILDFOLDER/PROJECTNAME.app/Contents/Resources/DESTINATIONFOLDERNAME
The mkdir commands are only to ensure that the folders are generated, if they were deleted.
So apparently the CMake method also works for directories.
target_sources(${QT_IOS_TARGET} PRIVATE ${_resource})
set_source_files_properties(${_resource} PROPERTIES MACOSX_PACKAGE_LOCATION Resources)
It will just be added at the root directory of the bundle and not within the Resources.
If the embedded file is not too big, you might consider :
in your source tree, generating a C++ file embedding that file as a constant array. For example, if your file contains just hello, world with a new line, you could have something like
/// file contents.cc
const char file_contents[] = "hello, world\n";
and at the beginning of your program (perhaps in your main function, before your QApplication) call a C++ function which writes such a file (perhaps in /tmp/).
in your build automation (e.g your Makefile or your qmake things), have something which generates the C++ contents.cc file from the genuine source
This is with a POSIX/Linux point of view, adapt my answer to your iOS.
Considering a folder (called parent_folder) containing an empty folder (called empty_son_folder) and another one that is not empty (called not_empty_son_folder) and the following exports_sources method:
exports_sources = ["parent_folder*"]
Only not_empty_son_folder is exported.
Is there a way with conan to force to copy an empty folder in export source method?
As #Yumnosch said it is possible to add a dummy file to force conan to include this folder or create this folder later in the receipe (#drodri's solution).
If the need is to have files generated by some test programs, both solutions work.
It is also possible to create such a folder directly in the test program that needs it.
I'm using Conan as a dependency manager for C++ and I want to create a package which requires a compiled file from another, already created, Conan-package.
I'm currently trying to create a package for the OpenStreetMap-Library OSM-binary (https://github.com/scrosby/OSM-binary.git).
The Makefile for this project (which can be found at ./OSM-binary/src/Makefile) requires a file called protoc from the protobuf-project (https://github.com/google/protobuf). This protoc-file can be found after compiling the protobuf-project in ./protobuf/src.
Without this file compiling the OSM-sources will fail with an error: make: ../protoc: Command not found
The Problem
As conan's documentation suggests to copy my needed files to folders in my package, e.g header-files to ./include, libs to ./lib, etc.
According to this, after building the protobuf-project via make, I'm copying the mentioned file via
def package(self):
self.copy("*.so", dst="lib", keep_path=False)
self.copy("protoc", dst="scripts", src="./protobuf/src")
to an folder called "scripts".
But at this point the black magic starts.
My first question is, how can I access any of these packed files (e. g. the *.so files or any other files (here the protoc-file) which are present in an package) from another package?
For me, even after reading conan's documentation, it's not clear how conan stores it's packed files and how to access these or any other files packed in the previous step.
Now back at the OSM-Project my approach would be setting the correct path manually in the Makefile via the tools.replace command.
First I declared the protobuf-packaged as an requirement
requires = "protobuf/2.5.0#test/testing"
and replaced the corresponding lines (in version 1.3.3, line 7) in the osm-Makefile with the correct path to the protoc-file.
tools.replace_in_file("OSM-binary/src/Makefile",
"PROTOC ?= protoc",
"PROTOC ?= <path-to-file>/protoc")
Now this leads us to my actual question: How do I get the path to the protoc-file which can be found in the protobuf-package in a folder called scripts, or is there any other way to do it?
Thanks,
Chris
There are different ways to access files from your dependencies:
If you want to directly run some file from your dependencies, you could use the self.run(...., run_environment=True), that will automatically set the PATH, LD_LIBRARY_PATH, etc so the binaries are found in the place where the package is installed. Find more information here
You can directly import the files you want from your dependencies, doing a copy (which is done before the build() method) of such files into the build folder, so they can be directly used there. The path you can use in your script is the current one, or self.build_folder. The imported files will be automatically removed after build, so they are not accidentally repackaged. Check imports docs
You can obtain information from your dependencies from the self.deps_cpp_info attribute. Check the reference here. That means you can get the paths to your protobuf dependency with something like
def build(self):
# Get the directory where protobuf package is installed
protoc_root = self.deps_cpp_info["protobuf"].rootpath
# Note this is a list
protoc_bin_paths = self.deps_cpp_info["protobuf"].bin_paths
I'm creating a simple RPM installer, I just have to copy files to a directory structure I create in the %install process.
The %install process is fine, I create the following folder /opt/company/application/ with the command mkdir -p %{buildroot}/opt/company/%{name} and then I proceed to copy the files and subdirectories from my package. I've tried to install it and it works.
The doubt I have comes when uninstalling. I want to remove the folder /opt/company/application/ and I thought you're supposed to use %{buildroot} anywhere when referencing the install location. Because my understanding is the user might have a different structure and you can't assume that rmdir /opt/company/%{name}/ will work. Using that command in the %postun section deletes succesfully the directories whereas using rmdir ${buildroot}/opt/company/%{name} doesn't delete the folders.
My question is, shouldn't you be using ${buildroot} in the %postun in order to get the proper install location? If that's not the case, why?
Don't worry about it. If you claim the directory as your own in the %files section, RPM will handle it for you.
FYI, %{buildroot} probably won't exist on the target machine.
Even though I have GOPATH properly set, I still can't get "go build" or "go run" to find my own packages. What am I doing wrong?
$ echo $GOROOT
/usr/local/go
$ echo $GOPATH
/home/mitchell/go
$ cat ~/main.go
package main
import "foobar"
func main() { }
$ cat /home/mitchell/go/src/foobar.go
package foobar
$ go build main.go
main.go:3:8: import "foobar": cannot find package
It does not work because your foobar.go source file is not in a directory called foobar. go build and go install try to match directories, not source files.
Set $GOPATH to a valid directory, e.g. export GOPATH="$HOME/go"
Move foobar.go to $GOPATH/src/foobar/foobar.go and building should work just fine.
Additional recommended steps:
Add $GOPATH/bin to your $PATH by: PATH="$GOPATH/bin:$PATH"
Move main.go to a subfolder of $GOPATH/src, e.g. $GOPATH/src/test
go install test should now create an executable in $GOPATH/bin that can be called by typing test into your terminal.
Although the accepted answer is still correct about needing to match directories with package names, you really need to migrate to using Go modules instead of using GOPATH. New users who encounter this problem may be confused about the mentions of using GOPATH (as was I), which are now outdated. So, I will try to clear up this issue and provide guidance associated with preventing this issue when using Go modules.
If you're already familiar with Go modules and are experiencing this issue, skip down to my more specific sections below that cover some of the Go conventions that are easy to overlook or forget.
This guide teaches about Go modules: https://golang.org/doc/code.html
Project organization with Go modules
Once you migrate to Go modules, as mentioned in that article, organize the project code as described:
A repository contains one or more modules. A module is a collection of
related Go packages that are released together. A Go repository
typically contains only one module, located at the root of the
repository. A file named go.mod there declares the module path: the
import path prefix for all packages within the module. The module
contains the packages in the directory containing its go.mod file as
well as subdirectories of that directory, up to the next subdirectory
containing another go.mod file (if any).
Each module's path not only serves as an import path prefix for its
packages, but also indicates where the go command should look to
download it. For example, in order to download the module
golang.org/x/tools, the go command would consult the repository
indicated by https://golang.org/x/tools (described more here).
An import path is a string used to import a package. A package's
import path is its module path joined with its subdirectory within the
module. For example, the module github.com/google/go-cmp contains a
package in the directory cmp/. That package's import path is
github.com/google/go-cmp/cmp. Packages in the standard library do not
have a module path prefix.
You can initialize your module like this:
$ go mod init github.com/mitchell/foo-app
Your code doesn't need to be located on github.com for it to build. However, it's a best practice to structure your modules as if they will eventually be published.
Understanding what happens when trying to get a package
There's a great article here that talks about what happens when you try to get a package or module: https://medium.com/rungo/anatomy-of-modules-in-go-c8274d215c16
It discusses where the package is stored and will help you understand why you might be getting this error if you're already using Go modules.
Ensure the imported function has been exported
Note that if you're having trouble accessing a function from another file, you need to ensure that you've exported your function. As described in the first link I provided, a function must begin with an upper-case letter to be exported and made available for importing into other packages.
Names of directories
Another critical detail (as was mentioned in the accepted answer) is that names of directories are what define the names of your packages. (Your package names need to match their directory names.) You can see examples of this here: https://medium.com/rungo/everything-you-need-to-know-about-packages-in-go-b8bac62b74cc
With that said, the file containing your main method (i.e., the entry point of your application) is sort of exempt from this requirement.
As an example, I had problems with my imports when using a structure like this:
/my-app
├── go.mod
├── /src
├── main.go
└── /utils
└── utils.go
I was unable to import the code in utils into my main package.
However, once I put main.go into its own subdirectory, as shown below, my imports worked just fine:
/my-app
├── go.mod
├── /src
├── /app
| └── main.go
└── /utils
└── utils.go
In that example, my go.mod file looks like this:
module git.mydomain.com/path/to/repo/my-app
go 1.14
When I saved main.go after adding a reference to utils.MyFunction(), my IDE automatically pulled in the reference to my package like this:
import "git.mydomain.com/path/to/repo/my-app/src/my-app"
(I'm using VS Code with the Golang extension.)
Notice that the import path included the subdirectory to the package.
Dealing with a private repo
If the code is part of a private repo, you need to run a git command to enable access. Otherwise, you can encounter other errors This article mentions how to do that for private Github, BitBucket, and GitLab repos: https://medium.com/cloud-native-the-gathering/go-modules-with-private-git-repositories-dfe795068db4
This issue is also discussed here: What's the proper way to "go get" a private repository?
I solved this problem by set my go env GO111MODULE to off
go env -w GO111MODULE=off
Note: setting GO111MODULE=off will turn off the latest GO Modules feature.
Reference: Why is GO111MODULE everywhere, and everything about Go Modules (updated with Go 1.17)
GO111MODULE with Go 1.16
As of Go 1.16, the default behavior is GO111MODULE=on, meaning that if
you want to keep using the old GOPATH way, you will have to force Go
not to use the Go Modules feature:
export GO111MODULE=off
In the recent go versions from 1.14 onwards, we have to do go mod vendor before building or running, since by default go appends -mod=vendor to the go commands.
So after doing go mod vendor, if we try to build, we won't face this issue.
Edit: since you meant GOPATH, see fasmat's answer (upvoted)
As mentioned in "How do I make go find my package?", you need to put a package xxx in a directory xxx.
See the Go language spec:
package math
A set of files sharing the same PackageName form the implementation of a package.
An implementation may require that all source files for a package inhabit the same directory.
The Code organization mentions:
When building a program that imports the package "widget" the go command looks for src/pkg/widget inside the Go root, and then—if the package source isn't found there—it searches for src/widget inside each workspace in order.
(a "workspace" is a path entry in your GOPATH: that variable can reference multiple paths for your 'src, bin, pkg' to be)
(Original answer)
You also should set GOPATH to ~/go, not GOROOT, as illustrated in "How to Write Go Code".
The Go path is used to resolve import statements. It is implemented by and documented in the go/build package.
The GOPATH environment variable lists places to look for Go code.
On Unix, the value is a colon-separated string.
On Windows, the value is a semicolon-separated string.
On Plan 9, the value is a list.
That is different from GOROOT:
The Go binary distributions assume they will be installed in /usr/local/go (or c:\Go under Windows), but it is possible to install them in a different location.
If you do this, you will need to set the GOROOT environment variable to that directory when using the Go tools.
TL;DR: Follow Go conventions! (lesson learned the hard way), check for old go versions and remove them. Install latest.
For me the solution was different. I worked on a shared Linux server and after verifying my GOPATH and other environment variables several times it still didn't work. I encountered several errors including 'Cannot find package' and 'unrecognized import path'. After trying to reinstall with this solution by the instructions on golang.org (including the uninstall part) still encountered problems.
Took me some time to realize that there's still an old version that hasn't been uninstalled (running go version then which go again... DAHH) which got me to this question and finally solved.
Running go env -w GO111MODULE=auto worked for me
Without editing GOPATH or anything, in my case just worked the following:
/app
├── main.go
├── /utils
└── utils.go
Import packages where needed. This can be unintuitive, because it isn't relative to the app path. You need to add the app in the package path too:
main.go:
package main
import(
"app/util"
)
Being in app directory, run:
go mod init app
go get <package/xxx>
go build main.go / go run main.go
You should be good to go.
GOPATH = /home/go
appPath = /home/projects/app
Create a proper go.mod and go.sum with go mod init app (delete old before)
After that resolve all dependencies like missing packages with go get github.com/example/package.
In simple words you can solve the import problem even with GO111MODULE=on with the following syntax for import:
import <your_module_name>/<package_name>
your_module_name -> module name which can be found in the go.mod file of the module as the first line.
example: github.com/nikhilg-hub/todo/ToDoBackend
package_name -> Path to your package within module.
example: orm
So the import statement would look like:
import "github.com/nikhilg-hub/todo/ToDoBackend/orm"
According to me we need to specify the module name + package name because we may need a same package name in two or more different modules.
Note: If you are importing a package from same module still you need to specify the full import path like above.
If you have a valid $GOROOT and $GOPATH but are developing outside of them, you might get this error if the package (yours or someone else's) hasn't been downloaded.
If that's the case, try go get -d (-d flag prevents installation) to ensure the package is downloaded before you run, build or install.
GOROOT should be set to your installation directory (/usr/local/go).
GOPATH should be set to your working directory (something like /home/username/project_folder).
GOPATH should not be set to GOROOT as your own project may need to install packages, and it's not recommended to have those packages in the Go installation folder. Check out this link for more.
For me none of the above solutions worked. But my go version was not the latest one. I have downloaded the latest version and replaced the older version in my mac os after that it worked perfectly.
I had a similar problem when building a docker file:
[1/3] STEP 9/9: RUN CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build -a -o manager main.go
api/v1alpha1/XXX.go:5:2: cannot find package "." in:
/workspace/client/YYY/YYY.go
This only appeared when building the Dockerfile, building locally worked fine.
The problem turned out to be a missing statement in my Dockerfile:
COPY client/ client/
I do not understand why this happens, we must be able to import from wherever our file is in its nest, since I have discovered that if we have more than one nest this will throw an error.
package main
import (
"fmt"
"indexer/source/testPackage3" // this will be show a GOROOT error.
"indexer/testPackage"
"indexer/testPackage2"
)
func main() {
fmt.Println("Agile content indexer -")
fmt.Println(testPackage.Greeting())
fmt.Println(testPackage2.Greeting())
fmt.Println(testPackage3.Greeting())
}
├── testPackage2
│ ├── entry2.go
│ └── source
│ └── entry3.go
To conclude, I just want to tell you, the entry3.go file will not work when imported into my main file, which in this case is (main.go), I do not understand why, therefore, I have simply chosen to use a depth folder in the packages I need to export.
entry.go, entry2.go will work perfectly when imported, but entry3.go will not work..
In addition, both the directory and the name of the package must be the same so that they work properly when importing them.
Have you tried adding the absolute directory of go to your 'path'?
export PATH=$PATH:/directory/to/go/