Log Explorer and queries in GCP - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ service_behavior

intermediate

Understanding Log Explorer Query Output

You run this Log Explorer query in Google Cloud Platform:

resource.type = "gce_instance"
severity = "ERROR"
"disk"

What will the query return?

A All log entries from Compute Engine instances regardless of severity that mention the word 'disk'.

B All log entries from any resource with severity ERROR that mention the word 'disk'.

C All log entries from Compute Engine instances with severity ERROR that mention the word 'disk'.

D All log entries from Compute Engine instances with severity ERROR but excluding those mentioning 'disk'.

💡 Hint

Look at the resource type and severity filters carefully.

The query filters logs to only those from Compute Engine instances (resource.type = "gce_instance") with severity ERROR and containing the word 'disk'.

🧠 Conceptual

intermediate

Log Explorer Query Syntax for Time Filtering

Which of these Log Explorer queries correctly filters logs from the last 24 hours?

A timestamp >= timestamp_sub(current_timestamp(), interval 24 hour)

B timestamp >= "-24h"

C timestamp >= "2024-04-25T00:00:00Z"

D timestamp >= "2024-04-26T00:00:00Z"

💡 Hint

Log Explorer supports relative time syntax like '-24h'.

Log Explorer supports relative time strings like '-24h' in queries. SQL-like functions are not valid, and fixed timestamps do not generally represent 'last 24 hours' without knowing the current time.

❓ Configuration

advanced

Correct Query to Extract HTTP Status Codes

You want to find all HTTP request logs with status code 500 in Log Explorer. Which query is correct?

A httpRequest.status = 500

B protoPayload.status = 500

C jsonPayload.status = 500

D status = 500

💡 Hint

HTTP request logs use a specific field for status codes.

The field httpRequest.status contains the HTTP status code in GCP logs. Other fields are incorrect or do not exist for this purpose.

❓ security

advanced

Detecting Unauthorized Access Attempts Using Log Explorer

Which Log Explorer query best detects unauthorized access attempts to Cloud Storage buckets?

A resource.type = "gcs_bucket" AND protoPayload.status.code = 7

B resource.type = "gcs_bucket" AND protoPayload.status.code = 16

C resource.type = "gcs_bucket" AND protoPayload.authenticationInfo.principalEmail = "[e-mail]"

D resource.type = "gcs_bucket" AND severity = "ERROR"

💡 Hint

Look for the status code that means permission denied.

Status code 7 means 'PERMISSION_DENIED' in GCP logs, which indicates unauthorized access attempts.

✅ Best Practice

expert

Optimizing Log Explorer Queries for Performance

You have a large volume of logs. Which query practice improves Log Explorer performance the most?

A Use wildcard characters (*) in text search to match all patterns.

B Use only text search terms without filters to catch all logs.

C Use OR conditions extensively to include many log types.

D Use resource.type and severity filters before text search terms.

💡 Hint

Filtering by structured fields first reduces data scanned.

Filtering by resource.type and severity first narrows logs quickly, improving query speed and reducing cost.

Practice

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

easy

A. To manage user permissions

B. To create virtual machines

C. To search and filter logs generated by cloud resources

D. To deploy applications automatically

Solution

1. Step 1: Understand Log Explorer's role

   Log Explorer is designed to help users find specific log entries by searching and filtering logs.

2. Step 2: Compare with other options

   Creating VMs, managing permissions, and deploying apps are done by other GCP services, not Log Explorer.

3. Final Answer:

   To search and filter logs generated by cloud resources -> Option C

4. Quick Check:

   Log Explorer = Search and filter logs [OK]

Hint: Log Explorer is for logs, not for VMs or permissions [OK]

Common Mistakes:

• Confusing Log Explorer with Compute Engine
• Thinking it manages user roles
• Assuming it deploys apps automatically

2. Which of the following is the correct syntax to filter logs for entries where the severity is ERROR in Log Explorer?

easy

A. severity = "ERROR"

B. severity == "ERROR"

C. severity="ERROR"

D. severity = ERROR

Solution

1. Step 1: Recall Log Explorer filter syntax

   Log Explorer uses single equals (=) with quotes around string values.

2. Step 2: Check each option

   severity = "ERROR" uses correct syntax: single equals (=) with quotes around string values. Omitting quotes, using double equals, or missing spaces around the operator are incorrect.

3. Final Answer:

   severity = "ERROR" -> Option A

4. Quick Check:

   Use = and quotes for strings [OK]

Hint: Use = and quotes for string filters in Log Explorer [OK]

Common Mistakes:

• Using == instead of =
• Omitting quotes around string values
• Missing spaces around =

3. Given the query resource.type = "gce_instance" AND severity = "WARNING", what kind of log entries will this return?

medium

A. All logs from any resource with severity WARNING

B. Logs from Google Compute Engine instances with any severity

C. Logs from any resource with severity ERROR or WARNING

D. Logs from Google Compute Engine instances with severity WARNING

Solution

1. Step 1: Analyze the query conditions

   The query filters logs where resource.type equals "gce_instance" AND severity equals "WARNING".

2. Step 2: Understand the AND operator effect

   Both conditions must be true, so logs must be from GCE instances and have WARNING severity.

3. Final Answer:

   Logs from Google Compute Engine instances with severity WARNING -> Option D

4. Quick Check:

   AND means both conditions true [OK]

Hint: AND means both filters must match logs [OK]

Common Mistakes:

• Thinking OR is used instead of AND
• Ignoring resource.type filter
• Assuming severity includes ERROR

4. You wrote this query in Log Explorer: resource.type = "gce_instance" OR severity = "ERROR" AND timestamp > "2024-01-01T00:00:00Z". Why might this not return expected results?

medium

A. Because AND has higher precedence than OR, so the query groups incorrectly

B. Because timestamp filter syntax is invalid

C. Because severity cannot be combined with resource.type

D. Because OR operator is not supported in Log Explorer

Solution

1. Step 1: Understand operator precedence in Log Explorer

   AND has higher precedence than OR, so the query is read as resource.type = "gce_instance" OR (severity = "ERROR" AND timestamp > ...).

2. Step 2: Identify grouping issue

   This means logs with resource.type "gce_instance" are included regardless of timestamp or severity, which may not be intended.

3. Final Answer:

   Because AND has higher precedence than OR, so the query groups incorrectly -> Option A

4. Quick Check:

   AND binds tighter than OR [OK]

Hint: Use parentheses to group AND/OR conditions correctly [OK]

Common Mistakes:

• Ignoring operator precedence
• Assuming OR has higher precedence
• Thinking OR is unsupported

5. You want to find logs from Compute Engine instances that either have severity ERROR or occurred after March 1, 2024. Which query correctly expresses this in Log Explorer?

hard

A. (resource.type = "gce_instance" AND severity = "ERROR") OR timestamp > "2024-03-01T00:00:00Z"

B. resource.type = "gce_instance" AND (severity = "ERROR" OR timestamp > "2024-03-01T00:00:00Z")

C. resource.type = "gce_instance" OR severity = "ERROR" AND timestamp > "2024-03-01T00:00:00Z"

D. resource.type = "gce_instance" AND severity = "ERROR" OR timestamp > "2024-03-01T00:00:00Z"

Solution

1. Step 1: Understand the requirement

   We want logs from GCE instances where severity is ERROR or logs from GCE instances after March 1, 2024.

2. Step 2: Analyze each option's logic

   resource.type = "gce_instance" AND (severity = "ERROR" OR timestamp > "2024-03-01T00:00:00Z") groups severity and timestamp with OR inside parentheses combined with resource.type using AND, matching the requirement.

3. Step 3: Check other options

   (resource.type = "gce_instance" AND severity = "ERROR") OR timestamp > "2024-03-01T00:00:00Z" includes logs after March 1 from any resource, not just GCE instances. The remaining options lack parentheses, causing wrong precedence.

4. Final Answer:

   resource.type = "gce_instance" AND (severity = "ERROR" OR timestamp > "2024-03-01T00:00:00Z") -> Option B

5. Quick Check:

   Use parentheses to combine OR inside AND [OK]

Hint: Use parentheses to group OR inside AND correctly [OK]

Common Mistakes:

• Missing parentheses causing wrong logic
• Including timestamp filter outside resource.type scope
• Assuming OR has same precedence as AND