Cloud Logging overview in GCP - Step-by-Step Execution

Process Flow - Cloud Logging overview

Application or Service

↓

Generate Logs

↓

Send Logs to Cloud Logging

↓

Cloud Logging Storage

↓

View & Analyze Logs in Console

↓

Set Alerts or Export Logs

Logs are created by apps or services, sent to Cloud Logging, stored, then viewed or used for alerts.

Execution Sample

GCP

gcloud logging write my-log "User login successful" --severity=INFO

# View recent logs
gcloud logging read "resource.type=gae_app" --limit=5

Write a log entry and then read recent logs from a Google App Engine app.

Process Table

Step	Action	Command/Process	Result/Output
1	Write log entry	gcloud logging write my-log "User login successful" --severity=INFO	Log entry 'User login successful' saved to 'my-log' with INFO severity
2	Send log to Cloud Logging	Automatic by gcloud command	Log stored in Cloud Logging backend
3	Read recent logs	gcloud logging read "resource.type=gae_app" --limit=5	Displays up to 5 recent logs from App Engine
4	Exit	No more commands	End of log write and read process

💡 No more commands to execute; logs written and read successfully.

Status Tracker

Variable	Start	After Step 1	After Step 3	Final
Log Entry Content	None	"User login successful"	"User login successful"	"User login successful"
Log Storage Status	Empty	Stored in Cloud Logging	Stored in Cloud Logging	Stored in Cloud Logging
Logs Retrieved	None	None	Up to 5 recent logs shown	Up to 5 recent logs shown

Key Moments - 3 Insights

Why do we not see the log immediately after writing it?

Logs may take a short moment to appear in Cloud Logging after writing, but the execution_table shows the write command completes before reading logs.

What does the severity level mean in the log write command?

Severity indicates the importance of the log (INFO here means normal operation). See Step 1 in execution_table where severity=INFO is set.

Can we read logs from any service with the same command?

No, the filter in Step 3 limits logs to App Engine (resource.type=gae_app). To read other logs, change the filter accordingly.

Visual Quiz - 3 Questions

Look at the execution_table, what is the result of Step 1?

A Logs displayed on screen

B Log entry saved with INFO severity

C Log entry deleted

D No action taken

💡 Hint

Check the 'Result/Output' column for Step 1 in execution_table

At which step do logs get stored in Cloud Logging?

A Step 2

B Step 1

C Step 3

D Step 4

💡 Hint

Look at the 'Action' and 'Result/Output' columns for Step 2 in execution_table

If you want to see logs from Compute Engine instead of App Engine, what changes in Step 3?

A Increase limit to 10

B Change severity to ERROR

C Change filter to resource.type=compute_instance

D No change needed

💡 Hint

See the filter used in Step 3's command in execution_table

Concept Snapshot

Cloud Logging collects logs from apps/services.
Use 'gcloud logging write' to add logs.
Logs stored centrally in Cloud Logging.
Use 'gcloud logging read' with filters to view logs.
Severity levels mark log importance.
Logs can trigger alerts or exports.

Full Transcript

Cloud Logging overview shows how logs are created by applications or services and sent to Cloud Logging for storage. Using the gcloud command line, you can write a log entry with a message and severity level. The log is then stored in Cloud Logging automatically. Later, you can read recent logs by filtering on resource types like App Engine. This process helps monitor and analyze system behavior. Severity levels help classify logs by importance. Filters let you focus on logs from specific services. Logs can also be used to trigger alerts or be exported for further analysis.

Practice

1. What is the main purpose of Cloud Logging in Google Cloud Platform?

easy

A. To store large files in the cloud

B. To create virtual machines automatically

C. To manage user permissions and roles

D. To collect and display logs from cloud resources in one place

Solution

1. Step 1: Understand Cloud Logging's role

   Cloud Logging collects logs from various cloud resources and shows them centrally.

2. Step 2: Compare options with this role

   Only To collect and display logs from cloud resources in one place describes collecting and displaying logs; others describe unrelated services.

3. Final Answer:

   To collect and display logs from cloud resources in one place -> Option D

4. Quick Check:

   Cloud Logging = centralized log collection [OK]

Hint: Cloud Logging is about logs, not VMs or storage [OK]

Common Mistakes:

• Confusing logging with VM creation
• Thinking it manages user permissions
• Mixing it up with storage services

2. Which of the following is the correct gcloud command to read logs from Cloud Logging?

easy

A. gcloud logging read "resource.type=gae_app"

B. gcloud compute instances list

C. gcloud storage buckets create my-bucket

D. gcloud iam roles describe admin

Solution

1. Step 1: Identify the command for reading logs

   The command to read logs uses 'gcloud logging read' followed by a filter.

2. Step 2: Check each option

   gcloud logging read "resource.type=gae_app" uses 'gcloud logging read' correctly; others relate to compute, storage, or IAM.

3. Final Answer:

   gcloud logging read "resource.type=gae_app" -> Option A

4. Quick Check:

   Log reading command starts with 'gcloud logging read' [OK]

Hint: Look for 'logging read' in the command to find logs [OK]

Common Mistakes:

• Using compute or storage commands instead of logging
• Missing the 'read' keyword after 'logging'
• Confusing IAM commands with logging commands

3. What will be the output of this command?
gcloud logging read "severity=ERROR" --limit 2 --format json

medium

A. A JSON list of the 2 most recent ERROR severity log entries

B. A list of all logs regardless of severity

C. An error message about invalid command syntax

D. A list of 2 logs with severity INFO

Solution

1. Step 1: Understand the command parameters

   The command reads logs filtered by severity=ERROR, limits output to 2 entries, and formats output as JSON.

2. Step 2: Analyze expected output

   It returns a JSON list of the 2 most recent logs with ERROR severity, not all logs or INFO logs.

3. Final Answer:

   A JSON list of the 2 most recent ERROR severity log entries -> Option A

4. Quick Check:

   Filter + limit + JSON format = filtered JSON logs [OK]

Hint: Filter by severity and limit controls output count [OK]

Common Mistakes:

• Ignoring the severity filter
• Expecting all logs instead of limited ones
• Confusing severity levels

4. You run this command but get no output:
gcloud logging read "severity=CRITICAL" --limit 5
What is the most likely reason?

medium

A. The command syntax is incorrect

B. There are no logs with severity CRITICAL in the selected time range

C. The gcloud tool is not installed

D. The limit flag cannot be used with severity filters

Solution

1. Step 1: Check command syntax

   The command syntax is correct; 'gcloud logging read' supports severity filters and limit.

2. Step 2: Consider reasons for no output

   No output usually means no matching logs exist for severity CRITICAL in the default time range.

3. Final Answer:

   There are no logs with severity CRITICAL in the selected time range -> Option B

4. Quick Check:

   No output often means no matching logs [OK]

Hint: No output? Check if logs exist for that severity [OK]

Common Mistakes:

• Assuming syntax error without checking
• Thinking limit flag is invalid with filters
• Ignoring that no logs might exist

5. You want to monitor your app's logs for errors and send alerts only when ERROR or higher severity logs appear. Which Cloud Logging feature should you use?

hard

A. Create a VM instance to process logs locally

B. Use Cloud Storage to save logs and check manually

C. Create a log-based metric with a filter for severity >= ERROR and set up an alerting policy

D. Run gcloud logging read manually every hour

Solution

1. Step 1: Identify monitoring and alerting needs

   You want automatic alerts on ERROR or higher severity logs.

2. Step 2: Match features to needs

   Log-based metrics with filters and alerting policies automate monitoring and alerts.

3. Step 3: Evaluate other options

   Manual checks or storing logs without alerts do not meet the requirement.

4. Final Answer:

   Create a log-based metric with a filter for severity >= ERROR and set up an alerting policy -> Option C

5. Quick Check:

   Log-based metrics + alerts = automated error monitoring [OK]

Hint: Use log-based metrics and alerts for automatic error notifications [OK]

Common Mistakes:

• Relying on manual log checks
• Using storage without alerting
• Creating unrelated VM instances