Git with Eclipse (4) - pushing local repositories to remote repositories

This post describes how to create a remote repository at GitHub and how to push a local repository to remote repository at GitHub using EGit.

Create a repository at GitHub

Firstly, we need a remote repository to start. I will use GitHub to host our remote repository. Sign up from here to get an account at GitHub. After sign in, click the  icon and select New repository.

In the next screen, give a name "HelloWorld" to our repository. You can also write a brief description about the repository, so other people will know what is your repository about. Choose Public as the repository type, so it can be accessed by anyone with restriction on modification. Private repository is available to paid users. If you tick Initialize this repository with a README, GitHub will create a read me file in the repository. We leave it as it is so we will have a clean repository. Then click the Create repository button and our HelloWorld repository is created.

In the next screen, you can see the HelloWorld repository is empty and GitHub provides several suggestions to start with. We will leave it for now and go back to HelloWold project in Eclipse.

SSH configuration

If you are going to use SSH protocol instead of HTTP for read and write access to the remote repository at GitHub, you have to configure the SSH key in Eclipse and GitHub.

Eclipse SSH configuration

Open Eclipse Preferences via Windows -> Preferences. Then go to General -> Network Connections -> SSH2. Select Key Management tab and click the Generate RSA Key... button. Eclipse will generate a public key (Copy the public key to a text file and it will be uploaded to GitHub later). Then enter a pass phrase in Passphrase: and Confirm passphrase: fields, it will be used to protect the private key. Click the Save Private Key... button to save the private key in your computer (usually it is saved in C:\Users\<username>\.ssh). Then go to General tab and enter the path of the private key (usually is C:\Users\<username>\.ssh) in SSH2 home: field. Click Apply button to save the configuration.

GitHub SSH configuration

Log in to GitHub. Then click the icon on the top right of the screen and select Settings in the menu. Choose SSH Keys in the navigator on the left. Then click Add SSH Key button and paste the Eclipse generated public key into the Key text box. Title field is optional.

Click Add key button and you will be asked to confirm your password. After the password is confirmed, the public key is added to GitHub. Now you are able to use SSH protocol to access your repositories at GitHub.

Push the local repository to remote repository

Firstly, we need a local repository to push. Create the HelloWorld project in Eclipse and share it in a local Git repository. Please refer to Git with Eclipse (3) - basic use cases in EGit with local repository for how to share project in local repository.

Secondly, because we created an empty repository at GitHub in previous step, we need to create a branch in the remote repository. Open Git perspective in Eclipse by selecting Windows -> Open Perspective -> Other....in the menu, then choose Git in the opened dialog.

In the Git perspective, expand HelloWorld repository, right click on Remotes and select Create Remote... In the menu.

Give a remote name in the opened dialog (Usually is origin by default) and select Configure push, then click OK.

The Configure Push dialog asks for the URI of the remote repository. we can copy the URI from HelloWorld repository at GitHub (we will use SSH URI in our example). Log in to GitHub and open HelloWorld repository. In the top section of the page, click on SSH and click theicon to copy the SSH URI.

Then go back to Eclipse. Click the Change... button in Configure Push dialog and paste the SSH URI into the URI: field in the opened Destination Git Repository dialog. Select ssh in the Protocol: field. Authentication Users: is git. Leave the rest as what it is and click Finish. You will be asked for the pass phrase. Enter the pass phrase you have set up in the SSH configuration and click OK.

Then click Save and Push button in Configure Push dialog.

A confirmation window will be shown once the repository is pushed to GitHub successfully.

Click OK to close the window. Log in to GitHub and open HelloWorld repository. You will see the HelloWorld project is now available at GitHub.

Now the HelloWorld project is ready to be forked or collaborated by other contributors. Also, you can fetch any updates in the HelloWorld project from GitHub and push your changes in HelloWorld project to GitHub. For how to clone a remote repository and fetch/push changes. Please read Git with Eclipse (5) - work with remote repositories (coming soon...).

Reference:

https://wiki.eclipse.org/EGit/User_Guide

Git with Eclipse (3) - basic use cases in EGit with local repository

This post introduces indexing files (stage), committing files and reverting changes in local repository with EGit. Here assume the project has already been shared to Git local repository. For how to share a project to Git local repository, please read Git with Eclipse - creating local repository with EGit in Eclipse. All screenshots below are from Eclipse Kepler.

Adding Files to staging area

Staging area is a new concept introduced by Git. Git has three main states of a file: modified, staged and committed. In a centralized version control system, there are only two states which are modified and committed. In Git, staged means that your file is marked in its current version to go into your next commit snapshot. It is useful when you have a major change in your project like adding a new feature. You cannot finish the work in one goal and you also cannot commit half completed work to the repository. In Git, you can stage your completed changes and continue your work. When you finish the whole implementation of the new feature, you can commit your work and all staged files will be committed in one snapshot. The following diagram shows the relationship of the three states.

To add a file into staging area in EGit, right click on the file and select Team -> Add to Index.

Once the file is added into staging area, a plus symbol will appear on the file and all parent folders of the file will have an asterisk symbol indicating it is staged.

EGit also allows to commit files not staged. In this case, those files will be staged and committed at the same time.

Committing Files to local repository 

Similar to centralized version control system, commit is straightforward. Right click on the project and select Team -> Commit... It will open a new dialog. In the upper textbox, you will have to enter a commit message. In the lower part of the dialog, you can select the files you want to commit. All staged files of the project are selected by default and you can also select staged files from other projects. In my example, the staged file from Project1 is selected by default and I can also select the staged file from Project2. Furthermore, if you click on the Show Untracked Files icon, those files not staged will also be displayed. And you are allowed to select those files. Click Commit button and all selected files will be committed to the local repository.

In Git, You can change your previous commit if you realize your previous commit is incomplete or your commit message needs modification. This is different from centralized version control system and it is a very convenient function to correct mistaken commits. To amend previous commit, click this icon on the right top of the commit message textbox. It will not add a new version to your committed files and your comment message in last commit will be overridden. However, this should only be used if the previous commit has not been pushed to a remote repository.

Reverting Changes 

There are several ways to revert changes in Git. Revert the changes in files or revert the changes in project.

Reverting changes in files

If you want to revert changes in one or more files, select the files and right click to popup the context menu. Select Replace With in the context menu, EGit provides several options to revert. Four of them relate to the local repository, HEAD Revision, Git Index, Previous Revision and Branch, Tag, or Reference...

HEAD Revision: This will replace the contents of the file with the HEAD revision. Any untracked changes and staged changes will be lost.
Git Index: This will replace the contents of the file with the contents in the staging area. Any untracked changes will be lost.
Previous Revision: This will replace the contents of the file with previous revision.
Branch, Tag, or Reference...: This enables you to revert your file to any branch, tag or reference revision.

Furthermore, you can use the Compare With to compare your files with any revision and revert changes line by line.

Reverting changes in project

If you want to revert changes in the whole project, right click on the project and select Team ->Reset... in the context menu. The Reset dialog will be popup. In the upper box, you can select any revision you want to reset to. In the bottom Reset type box, there are three types.

Soft (HEAD updated): This will only reset your current HEAD revision to the revision you select in the upper box. If the revision you selected is the same as your current HEAD revision, you will notice there is no change after reset. The untracked changes and staged changes will be retained.

Mixed (HEAD and index updated): This will do a Soft reset and reset the staging area. After Mixed reset, you will notice all your staged files become untracked. You can imagine as all the changes are removed out of staging area, but they still stay in your working directory.

Hard (HEAD, index, and working directory updated): This will do a Mixed reset and reset your working directory. After Hard reset, your working directory will also be reverted to the revision you selected, which means all uncommitted changes will be lost. You should be careful with Hard reset because you cannot bring your changes back.

There are other use cases of EGit in local repository. For a full guide of EGit usage, please refer to https://wiki.eclipse.org/EGit/User_Guide. For how to interact with remote Git repository in EGit, please read Git with Eclipse (4) - pushing local repositories to remote repositories.

Reference:

https://git-scm.com/book/en/v2/Getting-Started-Git-Basics

http://eclipsesource.com/blogs/tutorials/egit-tutorial/
https://wiki.eclipse.org/EGit/User_Guide

Git with Eclipse (2) - creating local repository with EGit in Eclipse

This post describes how to create a local repository using EGit. For how to configure EGit in Eclipse, please read Git with Eclipse (1) - configuration of EGit in Eclipse. All screenshots below are from Eclipse Kepler.

Create Local Repositories

Compare to centralised version control system SVN or CVS, you can easily create local repositories in Git. It enables you to version your work locally before sharing with other people.

Firstly, you need create a project in the workspace. Then right click on the project and select Team-> Share Project...

Select Git as the repository type and click Next.

In the next window, select your project and click Create button to create a Git repository. You can also tick 'Use or create repository in parent folder of project' to create the repository in the parent folder of the project. But it is not recommended and EGit will not allow if the project is under Eclipse workspace folder like my example in this post. The reason will be discussed later. 

In the popup dialog, specify a directory in Parent  directory. It can be any directory on your disk. But it is a good practice to use the parent directory of Eclipse workspace, because EGit will move the project folder from workspace folder to the repository folder. A new developer might be confused why he could not find the project folder in workspace. By doing this, it is easier to know where is the project folder on the disk. Then give a name of the repository. Click Finish to return to the Configure Git Repository dialog. EGit tells you the projects will be moved from the Current Location to the Target Location in the lower table of the dialog.

The Path within repository enables you to specify a sub folder inside the repository folder, and the projects will be moved to the sub folder you specified. I leave it blank so the project will be in the repository folder. Then click Finish button to create the repository.

Once the repository is created, you will notice a ">" sign appears next to the question mark icon on the project folder and some files are also have a question mark icon on them. The question mark icon means the project folder and all those files are new in the repository. And the ">" sign tells you there is modification inside project folder. You may also notice there is no question mark on the bin folder. It is because the folder has been added in to .gitignore file. All files and folders specified in .gitignore file will be ignored by Git and will not be shared into the repository. The files to be ignored are typically class files and sometimes the project settings files.

Now you are ready to commit your project to the local Git repository. For some basic use cases of EGit, please read Git with Eclipse (3) - basic use cases in EGit with local repository.

Eclipse workspace and repository working directory

Unlike SVN or CVS has to put the repository metadata folder inside the project folder, Git can put its metadata folder .git outside project folder. In my example, the .git folder is under GitRepository folder. I can share more than one projects in this repository and they all use the same .git folder to store the repository metadata.

According to EGit user guide, “it is not a good idea to make a project the root folder of your repository”. Because it will not possible to share more than one project in that repository.

And there are reasons why EGit keeps the repository working directory outside Eclipse workspace.

• When calculating the changes before committing, only active projects folders will be scanned. Irrelevant folders like .metadata or any inactive projects inside Eclipse workspace will be skipped.
• If .git folder is inside workspace folder, it is unclear whether Eclipse will do unwanted folder scan on the .git folder.
• Repository data is independent to the Eclipse workspace.

Reference:

http://eclipsesource.com/blogs/tutorials/egit-tutorial/

https://wiki.eclipse.org/EGit/User_Guide#Eclipse_Workspace_and_Repository_working_directory

Git with Eclipse (1) - configuration of EGit in Eclipse

This post provides a step by step configuration of an integrated Git tool in Eclipse - EGit. Read EGit for basic knowledge about Git/EGit.

Installing EGit in Eclipse

EGit is already included in the Eclipse releases after Juno, so you don't have to install it if you download Juno release or newer versions of Eclipse. For old version Eclipse, open Install wizard by clicking Install New Software... in Help menu.

Type http://download.eclipse.org/egit/updates in Work with: field. Select Eclipse Git Team Provider and click Next.

In the next window, click Next again to confirm your select. Then accept the terms of use and license agreement and click Finish to start installation. Restart Eclipse after installation finished.

I am using Eclipse Kepler version and all screenshots below are from Eclipse Kepler.

EGit User Configuration

To configure your username and Email address in EGit, open the Git configuration dialog by clicking Preference in Windows menu.

Then Type Git in the filter, select Configuration under Git. In User Settings tab, you can add your username and Email by clicking the Add Entry... button. In the pop up window, input user.name in the Key field and your username in the Value field. Click Add Entry... button again to add your Email by entering user.email in the Key field and your Email address in the Value field. The username and Email address are normally the same as your Git account. You can signup your Git account on GitHub website at GitHub.

The completed configuration window is looked like below. Click Apply button to save your configuration. And click OK button to close the window.

Now you are ready to create your first local repository. The username and Email address you configured above will be included in your every commit in EGit.

For how to create local repository with EGit, please read Git with Eclipse (2) - creating local repository with EGit in Eclipse

Reference: http://eclipsesource.com/blogs/tutorials/egit-tutorial/