Introduction to Git for DevOps Engineers

Welcome to the world of Git! As a new DevOps engineer, Git will become one of your most important tools. It helps manage and track changes to code, collaborate with other engineers, and supports automated workflows like Continuous Integration (CI) and Continuous Delivery (CD).

What is Git?

Git is a version control system (VCS) that tracks changes in files, usually code but can be used for anything, over time. It allows you to:

Track changes: See what changes have been made, who made them, and when.
Collaborate: Work on projects with others without messing up each other’s work.
Revert changes: Go back to a previous version of your code if something breaks.

Git is distributed, meaning each developer has a full copy of the code and history on their own machine. This makes it powerful and flexible for teams, and it’s essential for a modern software engineering life cycle.

Why is Git Important for DevOps?

As a principle of DevOps, there is a strong emphasis on automation, collaboration, and quick iterations. Git fits perfectly with these goals.

1. Collaboration Made Easy

Git allows multiple developers to work on the same code at the same time without worrying about interfering with each other's work. This makes it easy to collaborate effectively.

2. Continuous Integration/Continuous Deployment (CI/CD)

Git integrates seamlessly with CI/CD pipelines in Copado to automate the Salesforce development process. Copado allows you to automatically test, validate, and deploy your Salesforce code whenever changes are made in your Git repository. For example, when you retrieve code from Copado's GUI, it will automatically retrieve the commits from Git and execute Static Code Analysis to ensure code quality and compliance. This proactively eliminates issues before they reach production.

3. Version History

Git keeps a complete history of your codebase, so you can view changes over time, go back to older versions, and even fix mistakes by reverting to a previous state. This is especially helpful when perform deployments and rolling back changes.

4. Branching and Merging

With Git, you can branch off your main codebase to work on new features or fixes without disturbing the main code. Once you're done, you can merge your changes back into the main codebase. This allows for safer collaboration and more efficient workflows. Within a Copado context, this is automated through the use of the Copado Pipeline Tool.

Key Git Concepts You Need to Know

1. Repository

A Git repository (or "repo") is where your code lives. It's like a folder that contains all of your project files and the entire history of changes made to those files.

2. Clone

To start working with a Git repository, you first clone it to your local machine. This copies the repository and its history to your computer, allowing you to work on it locally.

git clone <repository-url>

3. Commit

A commit is a snapshot of your changes. It’s like taking a picture of your work at a particular moment. Each commit includes a message explaining what changes were made.

git commit -m "Added a new feature"

4. Stage

To prepare your changes for commit, you stage them using the git add command. This tells Git that you want to include the changes in the next commit.

git add {filename}

5. Push

Once you've made changes and committed them, you push them to the remote repository (the one on GitHub, GitLab, etc.) to share your work with others.

git push origin <branch-name>

6. Pull

To get the latest changes from the remote repository, you pull them into your local repository. This makes sure you're always working with the most up-to-date version of the code.

git pull origin <branch-name>

7. Branching

You can branch off your main project to work on new features or bug fixes without affecting the main codebase. Once your changes are ready, you can merge them back into the main branch.

git checkout -b <new-branch-name>

8. Merge

When you're finished with a branch, you can merge it back into your main code. This takes the changes from your branch and combines them with the main code.

git checkout main
git merge <branch-name>

9. Conflicts

Sometimes, Git can't automatically merge changes because two people edited the same part of the code. This is called a merge conflict. You'll need to manually fix the conflict, decide which changes to keep, and then commit the result.

A Basic Git Workflow for DevOps

Here is a sample Salesforce DevOps workflow to help you get started with Git in a DevOps environment:

Clone the repository to your local machine:
```
git clone <repository-url>
```
Create a branch to work on a new feature or fix:
```
git checkout -b feature/us-00001
```
Make changes to your code in Salesforce GUI.
Retrieve code from Salesforce GUI to your local machine.

sf project retrieve start -m CustomMetadata:SampleMetadata -o devbox

Stage the changes you want to keep:
```
git add .
```

Commit your changes with a meaningful message:

git commit -m "Fix bug in user authentication"

Push your changes to the remote repository:
```
git push origin <branch-name>
```
Create a Pull Request (PR) to merge your changes into the main branch. This is usually done through a platform like GitHub or GitLab.
Pull the latest changes from the main branch to stay up-to-date:
```
git pull origin main
```
Merge your branch back into the main branch once your changes have been reviewed and tested.

Certainly! Here's the "How to Read File Changes" section with code examples and explanations for understanding changes in Salesforce development, particularly in Git repositories integrated with Copado.

Advanced Topics

When you're starting to work with Git more frequently, you may realize that Microsoft's Visual Code is a great tool, but it's not necessarily the fastest way to work with Git. In addition, when building a DevOps workflow, you'll need to learn execute Git commands directly for optimizing your workflow for cost efficiency and speed.

1. `git status`

The git status command shows the current state of your working directory and staging area. It tells you which files have been modified, added, or deleted since the last commit.

git status

Example Output:

On branch feature/my-feature
Changes not staged for commit:
  (use "git add <file>..." to update what will be committed)
  (use "git restore <file>..." to discard changes in working directory)

        modified:   force-app/main/default/classes/MyClass.cls
        modified:   force-app/main/default/objects/Account/fields/MyField.field-meta.xml

no changes added to commit (use "git add" and/or "git commit -a")

What it shows:

The files that have been modified (e.g., MyClass.cls and MyField.field-meta.xml).
Files that need to be added (git add) to the staging area before committing.

2. `git diff`

The git diff command shows the differences between your working directory and the index (staging area), or between your last commit and the current changes. This is useful to understand the exact changes made in a file.

git diff

Example Output:

diff --git a/force-app/main/default/classes/MyClass.cls b/force-app/main/default/classes/MyClass.cls
index 5b43d9f..2c93f8e 100644
--- a/force-app/main/default/classes/MyClass.cls
+++ b/force-app/main/default/classes/MyClass.cls
@@ -1,5 +1,6 @@
 public class MyClass {
     public static String myMethod(String input) {
-        return input + ' processed';
+        return input + ' processed by Git';
     }
 }

What it shows:

Line-by-line changes between the previous and current version of the file.
In this example, the method myMethod was updated to change the returned string from ' processed' to ' processed by Git'.
Lines prefixed with - indicate deletions, while lines prefixed with + show additions.

3. `git log`

The git log command helps you view the commit history, showing you who made changes and when. This is especially useful to track changes to Salesforce metadata and code across multiple commits.

git log

Example Output:

commit 9f7d1234abcd5678ef90d1e3f4bc5d0e9f8a62d3
Author: Developer <[email protected]>
Date:   Wed Sep 1 12:34:56 2024 +0000

    Added validation to MyField field-meta.xml

commit 1a2b3c4d5e67890f1g2h3i4j5k6l7m8n9o0p1q2r
Author: Developer <[email protected]>
Date:   Tue Aug 31 09:21:45 2024 +0000

    Initial commit of MyClass.cls

What it shows:

Commit hashes (e.g., 9f7d1234abcd5678).
Commit messages describing what was changed (e.g., "Added validation to MyField field-meta.xml").
The author and date of each commit.

4. `git show`

The git show command displays the details of a specific commit, including the files that were changed and the diffs for each file.

git show <commit-hash>

Example Output:

commit 9f7d1234abcd5678ef90d1e3f4bc5d0e9f8a62d3
Author: Developer <[email protected]>
Date:   Wed Sep 1 12:34:56 2024 +0000

    Added validation to MyField field-meta.xml

diff --git a/force-app/main/default/objects/Account/fields/MyField.field-meta.xml b/force-app/main/default/objects/Account/fields/MyField.field-meta.xml
index 4e53d9b..d933c5f 100644
--- a/force-app/main/default/objects/Account/fields/MyField.field-meta.xml
+++ b/force-app/main/default/objects/Account/fields/MyField.field-meta.xml
@@ -1,5 +1,6 @@
 <fields>
     <fullName>MyField</fullName>
     <label>My Custom Field</label>
+    <validationRules>
+        <validationRule>Custom_Validation</validationRule>
+    </validationRules>
 </fields>

What it shows:

Detailed information about the specific commit, including the commit message and the exact changes made to Salesforce metadata (e.g., a new <validationRules> element added to MyField.field-meta.xml).

5. `git diff --staged`

This command shows the differences between the staging area and the last commit. Use this command to see the changes you've added (via git add) but haven’t committed yet.

git diff --staged

Example Output:

diff --git a/force-app/main/default/classes/MyClass.cls b/force-app/main/default/classes/MyClass.cls
index 5b43d9f..2c93f8e 100644
--- a/force-app/main/default/classes/MyClass.cls
+++ b/force-app/main/default/classes/MyClass.cls
@@ -1,5 +1,6 @@
 public class MyClass {
     public static String myMethod(String input) {
-        return input + ' processed';
+        return input + ' processed by Git';
     }
 }

What it shows:

Similar to git diff, but it only shows the differences of files that have been added to the staging area and are ready to be committed.

Git Diff Colors

Git diff colors are used to highlight the changes made in a file when comparing commit changes. Here are some common colors:

Green (+): Added lines.
Green highlights indicate new content that has been added to the file. This might be a new line of code, a new metadata element, or any content that wasn't in the file before.
Red (-): Removed lines.
Red highlights show what has been removed from the file since the last commit. These are lines that no longer exist in the updated version of the file.
Blue (in some diff tools): Changes or modified content.
Blue is often used to highlight lines where the content has been modified or changed. This means that the content of a line was altered (instead of entirely adding or removing it).

Conclusion

Git is a powerful tool that you'll use daily as a DevOps engineer. It helps you manage code, collaborate with your team, and integrate with CI/CD pipelines. By mastering the basics of Git, you’ll be well on your way to improving your software development and deployment processes.

Introduction to Git for DevOps Engineers

What is Git?

Why is Git Important for DevOps?

1. Collaboration Made Easy

2. Continuous Integration/Continuous Deployment (CI/CD)

3. Version History

4. Branching and Merging

Key Git Concepts You Need to Know

1. Repository

2. Clone

3. Commit

4. Stage

5. Push

6. Pull

7. Branching

8. Merge

9. Conflicts

A Basic Git Workflow for DevOps

Advanced Topics

1. git status

2. git diff

3. git log

4. git show

5. git diff --staged

Git Diff Colors

Conclusion

1. `git status`

2. `git diff`

3. `git log`

4. `git show`

5. `git diff --staged`