Buildpacks for source-based deployment in GCP - Step-by-Step Execution

Process Flow - Buildpacks for source-based deployment

Start: Source Code

↓

Detect Buildpack

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Buildpack Executes

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Compile & Build Image

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Deploy Container

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App Running

The source code is analyzed to detect the right buildpack, which builds the app image, then deploys it as a running container.

Execution Sample

GCP

gcloud run deploy myapp --source=./app-source
# Cloud Build detects buildpack
# Buildpack compiles and builds container
# Container deployed to Cloud Run

Deploy source code to Cloud Run using buildpacks that detect and build the app automatically.

Process Table

Step	Action	Input	Output	Notes
1	Start deployment	Source code folder	Trigger buildpack detection	User runs deploy command with source
2	Detect buildpack	Source code files	Select suitable buildpack	E.g., Node.js, Python, Java detected
3	Execute buildpack	Selected buildpack + source	Build container image	Buildpack compiles and packages app
4	Build image	Compiled app	Container image ready	Image stored in registry
5	Deploy container	Container image	App deployed and running	Cloud Run runs container
6	App running	Deployed container	App accessible via URL	User can access app
7	Exit	N/A	Deployment complete	Process ends successfully

💡 Deployment completes after container is running and accessible

Status Tracker

Variable	Start	After Step 2	After Step 3	After Step 4	After Step 5	Final
source_code	Provided	Provided	Provided	Provided	Provided	Provided
buildpack	None	Detected (e.g., Node.js)	Executing	Executed	Executed	Executed
container_image	None	None	Building	Built	Deployed	Deployed
app_status	Not running	Not running	Not running	Not running	Running	Running

Key Moments - 3 Insights

How does the system know which buildpack to use?

The system scans the source code files to detect language or framework signatures, then selects the matching buildpack as shown in step 2 of the execution table.

What happens if the buildpack fails to build the image?

The deployment stops before step 5; no container image is created or deployed. This is why step 4 must complete successfully before deployment.

Is the source code directly deployed to Cloud Run?

No, the source code is first compiled and packaged into a container image by the buildpack, then the container is deployed, as shown between steps 3 and 5.

Visual Quiz - 3 Questions

Look at the execution table, at which step is the container image created?

A Step 2

B Step 3

C Step 4

D Step 5

💡 Hint

Check the 'Output' column for when 'Container image ready' appears.

According to the variable tracker, what is the app status after step 5?

A Not running

B Running

C Building

D Failed

💡 Hint

Look at the 'app_status' row under 'After Step 5' column.

If the buildpack detection fails, which step will not be reached?

A Step 3

B Step 2

C Step 4

D Step 5

💡 Hint

Refer to the flow: buildpack must be detected before it can execute.

Concept Snapshot

Buildpacks detect app language from source code
Buildpacks compile and package app into container image
Container image deployed to Cloud Run
User runs 'gcloud run deploy --source' to trigger process
Buildpack automates build, no Dockerfile needed
Deployment ends when app container is running

Full Transcript

This visual execution shows how source-based deployment with buildpacks works on Google Cloud Run. First, the user provides source code and runs the deploy command. The system detects the appropriate buildpack by analyzing the source files. The buildpack then compiles and builds a container image from the source. Once the image is ready, it is deployed to Cloud Run as a container. Finally, the app runs and is accessible via a URL. Variables like source code, buildpack status, container image, and app status change step-by-step. Key moments clarify how buildpack detection works, what happens if build fails, and why source code is not deployed directly. The quizzes test understanding of when the container image is created, app status after deployment, and the importance of buildpack detection.