Claude Code transcript

6 prompts · 67 messages · 25 tool calls · 0 commits · 2 pages

#1

i want to provide a new standard command mysql-conn, which establishes a port forwarding to remote DB via AWS ssm.

the command does the following things:

  1. firstly run aws ssm list-documents --filters Key=Name,Values={env}-imprint-forward --query "DocumentIdentifiers[].Name" command to find out all possible forwarding targets. the ssm document's name will be named after the following pattern: {env}-imprint-forward-{db_name}-mysql-db. env is the environment's name, db_name is the name of the db. the command will extract env from AWS_PROFILE.

  2. after retrieving all ssm documents, list db_name, not the document's name itself, as a list for users to interact with. the interaction should be the same as what we have done as ctx command.

  3. use the follwing command to retrieve the bastion host for connection: aws ec2 describe-instances \ --filters "Name=tag:Name,Values=internal-ssm-bastion" "Name=instance-state-name,Values=running" \ --query "Reservations[].Instances[].InstanceId" --output text

  4. use the following command to establish the port forwrading with bastion host: aws ssm start-session \ --target \ --document-name \ --parameters localPortNumber=

you need to use the most efficient way to find an unused port. you should let me know your plan first before you implement it.

4 read · 1 task · 1 glob

Now I have a clear understanding of the patterns. Let me present my plan:

Plan for mysql-conn Command

Overview

Create a new command mysql-conn under pkg/cmd/mysqlconn/ that follows the same patterns as the ctx command.

Implementation Steps

  1. Create pkg/cmd/mysqlconn/mysqlconn.go with:
  2. MySQLConnOptions struct embedding *types.Options
  3. NewCmdMySQLConn() factory function

  4. Flag for --port (default: 13306)

  5. Core Logic Flow:

  6. Extract env from AWS_PROFILE (e.g., dev-imprint-admin → dev)
  7. Run aws ssm list-documents to get available SSM documents
  8. Parse document names to extract db_name from pattern {env}-imprint-forward-{db_name}-mysql-db
  9. Show interactive selection using promptui.Select (same as ctx)
  10. Get bastion instance ID via aws ec2 describe-instances

  11. Find unused port and start SSM session

  12. Unused Port Detection (Most Efficient Method):

The most efficient approach is to let the OS assign a free port using Go's net package: go func findUnusedPort(preferredPort int) (int, error) { // Try preferred port first ln, err := net.Listen("tcp", fmt.Sprintf(":%d", preferredPort)) if err == nil { ln.Close() return preferredPort, nil } // Let OS assign a free port ln, err = net.Listen("tcp", ":0") if err != nil { return 0, err } port := ln.Addr().(*net.TCPAddr).Port ln.Close() return port, nil }

This is more efficient than scanning ports because: - Single syscall to OS to check/assign port - No race conditions (OS handles atomicity) - Falls back gracefully if preferred port is busy

  1. Register in pkg/cmd/root.go:
  2. Import mysqlconn package

  3. Add cmd.AddCommand(mysqlconn.NewCmdMySQLConn(opts))

  4. Tests in pkg/cmd/mysqlconn/mysqlconn_test.go:

  5. Table-driven tests for env extraction
  6. Test document name parsing
  7. Test port finding logic
  8. Mock AWS CLI calls for unit tests

Files to Create/Modify

File Action
pkg/cmd/mysqlconn/mysqlconn.go Create
pkg/cmd/mysqlconn/mysqlconn_test.go Create
pkg/cmd/root.go Modify (add import + registration)

Questions Before Implementation

  1. Env extraction: Should I extract env as the first segment before -imprint? (e.g., dev-imprint-admin → dev, staging-imprint-admin → staging)

  2. Error handling: If no SSM documents are found, should it show an error or gracefully exit?

  3. Port behavior: Should the command print the port being used (to stderr) so users know where to connect?

Do you approve this plan? Any changes you'd like before I implement?

#2

here's the answer for open question:

#3

[Request interrupted by user]

#4

the plan looks good except a few parts: 1. make sure you print out error messages if any steps are getting error; 2. before starting ssm session, you should let the user know that user need to run mysql -u <db_username> -h 127.0.0.1 -P <port_number> -p on another terminal to access the DB

here's the answer for open question: 1. you should use the entire AWS_PROFILE, don't extract anything 2. if no ssm documents are found, show the user they have no allowed forwarding target and exit 3. yes

4 edit · 3 todo · 2 write · 2 bash
#5

[Request interrupted by user for tool use]

#6

if profile doesn't need in the function, don't pass it in

4 bash · 3 edit · 1 todo

Done! Here's a summary of what was implemented:

Summary

Created the mysql-conn command with the following files:

pkg/cmd/mysqlconn/mysqlconn.go

  • Lists SSM documents matching {AWS_PROFILE}-imprint-forward-*-mysql-db pattern
  • Extracts database names from document names for user-friendly selection
  • Uses promptui.Select with fuzzy search (same UX as ctx command)
  • Gets bastion host instance ID via aws ec2 describe-instances
  • Finds unused port efficiently using Go's net.Listen (tries preferred port first, falls back to OS-assigned)
  • Prints connection instructions before starting SSM session
  • Supports --port / -p flag (default: 13306)

pkg/cmd/mysqlconn/mysqlconn_test.go

  • Table-driven tests for document name parsing
  • Tests for unused port finding
  • Tests for fuzzy search
  • Tests for command structure and flags
  • Test for missing AWS_PROFILE error

pkg/cmd/root.go

  • Registered mysql-conn command

Key behaviors:

  1. Error messages are printed for all failure cases
  2. Shows user instructions before establishing the connection: To connect to the database, run this command in another terminal: mysql -u <db_username> -h 127.0.0.1 -P <port> -p
  3. If no SSM documents found, shows "No allowed forwarding targets found for your profile." and exits gracefully
  4. Uses full AWS_PROFILE value as requested