jwsy / skaffold-example

skaffold-example of a mysql-rest API in Go

1. Requires a K8s cluster, I use Rancher desktop as shown here: https://medium.com/macoclock/rancher-desktop-setup-for-k8s-on-your-macos-laptop-6f1c576ceb48
2. Create an example database using the MySQL Tutorial https://www.mysqltutorial.org/mysql-sample-database.aspx
3. Write a simple Go api

Example Database db/

1. Download the sample database

   This tutorial provides a nice multi-table database named classicmodels

   https://www.mysqltutorial.org/how-to-load-sample-database-into-mysql-database-server.aspx

2. Run a mysql container and initialize it

   • With helm

     https://stackoverflow.com/questions/66501138/db-migration-in-helm-mysql-initializationfiles-causes-the-pod-to-crash

     helm install mysql --set auth.rootPassword=root bitnami/mysql
     
     kubectl cp mysqlsampledatabase.sql mysql-0:/tmp
     kubectl exec mysql-0 -- sh -c "mysql -uroot -proot < /tmp/mysqlsampledatabase.sql"
     kubectl exec mysql-0 -- mysql -uroot -proot -e "SHOW DATABASES;"
     kubectl exec mysql-0 -- mysql -uroot -proot -e "SHOW TABLES;"
     kubectl exec mysql-0 -- mysql -uroot -proot classicmodels -e "SELECT * FROM employees LIMIT 10;"

Simple API helm-deployment/

Use Skaffold to create a simple client that connects to the database that you can debug, based off of the official Skaffold examples: https://github.com/GoogleContainerTools/skaffold/tree/bcbdfe043c2f334f919fa2e6ae06aed4a7578486/examples/helm-deployment. Read the README in the helm-deployment directory

Note that as of Feb 2023, Skaffold doesn't seem to support go 1.20 so we use go 1.19 by using

• go 1.19 in go.mod and
• golang:1.19-alpine3.17 in the container images in Dockerfile

Get set up with in the helm-deployment/ directory

1. Install Skaffold, configure it for a local cluster skaffold config set --global local-cluster true

2. Install go locally brew install go, and it's OK to have go 1.20

3. Install Go VS Code Extension and install required modules like dlv, use cmd-shift-p to get the modules

4. Install the app dependencies

   go get github.com/gofiber/fiber/v2
   go get github.com/go-sql-driver/mysql
   go mod download
   go mod tidy

5. Set your go working directory to be helm-deployment, note that this step has already been done and go.work is checked in.

   go work init
   go work use helm-deployment 

6. Use skaffold debug --port-forward to debug, using .vscode/launch.json as shown below. The magic appeared to be to not set the cwd

   Browse to localhost:3000 and the API returns the JSONified results of the query SELECT * FROM employees LIMIT 10

   Example launch.json

   {
   // Use IntelliSense to learn about possible attributes.
   // Hover to view descriptions of existing attributes.
   // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
   "version": "0.2.0",
   "configurations": [
       {
       "name": "Skaffold debug",
       "type": "go",
       "request": "attach",
       "mode": "remote",
       "port": 56268,
       "host": "127.0.0.1",
       // "substitutePath": [
       //   {
       //       "from": "${workspaceFolder}",
       //       "to": "/code",
       //   },
       // ],
       }
   ]
   }

   Example log output

   $ skaffold debug --port-forward
   ...
   building
   ...
   Starting deploy...
   Helm release skaffold-helm not installed. Installing...
   NAME: skaffold-helm
   LAST DEPLOYED: Mon Mar  6 07:43:45 2023
   NAMESPACE: default
   STATUS: deployed
   REVISION: 1
   TEST SUITE: None
   Waiting for deployments to stabilize...
    - deployment/skaffold-helm is ready.
   Deployments stabilized in 4.261 seconds
   Port forwarding service/skaffold-helm-service in namespace default, remote port 3000 -> http://127.0.0.1:3000
   Listing files to watch...
    - skaffold-helm
   Press Ctrl+C to exit
   Not watching for changes...
   [skaffold-helm] API server listening at: [::]:56268
   [skaffold-helm] 2023-03-06T12:43:48Z warning layer=rpc Listening for remote connections (connections are not authenticated nor encrypted)
   [skaffold-helm]
   [skaffold-helm]  ┌───────────────────────────────────────────────────┐
   [skaffold-helm]  │                   Fiber v2.42.0                   │
   [skaffold-helm]  │               http://127.0.0.1:3000               │
   [skaffold-helm]  │       (bound on host 0.0.0.0 and port 3000)       │
   [skaffold-helm]  │                                                   │
   [skaffold-helm]  │ Handlers ............. 4  Processes ........... 1 │
   [skaffold-helm]  │ Prefork ....... Disabled  PID ................ 12 │
   [skaffold-helm]  └───────────────────────────────────────────────────┘
   [skaffold-helm]
   [install-go-debug-support] Installing runtime debugging support files in /dbg
   [install-go-debug-support] Installation complete
   Port forwarding pod/skaffold-helm-f55ddbdf6-96kgl in namespace default, remote port 56268 -> http://127.0.0.1:56268
   [skaffold-helm] / - Aloha!
   [skaffold-helm] <nil>
   [skaffold-helm] 2023-03-06T12:45:49Z error layer=rpc writing response:write tcp 127.0.0.1:56268->127.0.0.1:53180: use of closed network connection
   [skaffold-helm] / - Aloha!
   

   Expected output:

   $ curl localhost:3000
   {"employees":[{"employeeNumber":{"Int64":1002,"Valid":true},"lastName":{"String":"Murphy","Valid":true},"firstName":{"String":"Diane","Valid":true},"extension":{"String":"x5800","Valid":true},"email":{"String":"[e-mail]","Valid":true},"officeCode":{"String":"1","Valid":true},"reportsTo":{"Int64":0,"Valid":false},"jobTitle":{"String":"President","Valid":true}},{"employeeNumber":{"Int64":1056,"Valid":true},"lastName":{"String":"Patterson","Valid":true},"firstName":{"String":"Mary","Valid":true},"extension":{"String":"x4611","Valid":true},"email":{"String":"[e-mail]","Valid":true},"officeCode":{"String":"1","Valid":true},"reportsTo":{"Int64":1002,"Valid":true},"jobTitle":{"String":"VP Sales","Valid":true}},{"employeeNumber":{"Int64":1076,"Valid":true},"lastName":{"String":"Firrelli","Valid":true},"firstName":{"String":"Jeff","Valid":true},"extension":{"String":"x9273","Valid":true},"email":{"String":"[e-mail]","Valid":true},"officeCode":{"String":"1","Valid":true},"reportsTo":{"Int64":1002,"Valid":true},"jobTitle":{"String":"VP Marketing","Valid":true}},{"employeeNumber":{"Int64":1088,"Valid":true},"lastName":{"String":"Patterson","Valid":true},"firstName":{"String":"William","Valid":true},"extension":{"String":"x4871","Valid":true},"email":{"String":"[e-mail]","Valid":true},"officeCode":{"String":"6","Valid":true},"reportsTo":{"Int64":1056,"Valid":true},"jobTitle":{"String":"Sales Manager (APAC)","Valid":true}},{"employeeNumber":{"Int64":1102,"Valid":true},"lastName":{"String":"Bondur","Valid":true},"firstName":{"String":"Gerard","Valid":true},"extension":{"String":"x5408","Valid":true},"email":{"String":"[e-mail]","Valid":true},"officeCode":{"String":"4","Valid":true},"reportsTo":{"Int64":1056,"Valid":true},"jobTitle":{"String":"Sale Manager (EMEA)","Valid":true}},{"employeeNumber":{"Int64":1143,"Valid":true},"lastName":{"String":"Bow","Valid":true},"firstName":{"String":"Anthony","Valid":true},"extension":{"String":"x5428","Valid":true},"email":{"String":"[e-mail]","Valid":true},"officeCode":{"String":"1","Valid":true},"reportsTo":{"Int64":1056,"Valid":true},"jobTitle":{"String":"Sales Manager (NA)","Valid":true}},{"employeeNumber":{"Int64":1165,"Valid":true},"lastName":{"String":"Jennings","Valid":true},"firstName":{"String":"Leslie","Valid":true},"extension":{"String":"x3291","Valid":true},"email":{"String":"[e-mail]","Valid":true},"officeCode":{"String":"1","Valid":true},"reportsTo":{"Int64":1143,"Valid":true},"jobTitle":{"String":"Sales Rep","Valid":true}},{"employeeNumber":{"Int64":1166,"Valid":true},"lastName":{"String":"Thompson","Valid":true},"firstName":{"String":"Leslie","Valid":true},"extension":{"String":"x4065","Valid":true},"email":{"String":"[e-mail]","Valid":true},"officeCode":{"String":"1","Valid":true},"reportsTo":{"Int64":1143,"Valid":true},"jobTitle":{"String":"Sales Rep","Valid":true}},{"employeeNumber":{"Int64":1188,"Valid":true},"lastName":{"String":"Firrelli","Valid":true},"firstName":{"String":"Julie","Valid":true},"extension":{"String":"x2173","Valid":true},"email":{"String":"[e-mail]","Valid":true},"officeCode":{"String":"2","Valid":true},"reportsTo":{"Int64":1143,"Valid":true},"jobTitle":{"String":"Sales Rep","Valid":true}},{"employeeNumber":{"Int64":1216,"Valid":true},"lastName":{"String":"Patterson","Valid":true},"firstName":{"String":"Steve","Valid":true},"extension":{"String":"x4334","Valid":true},"email":{"String":"[e-mail]","Valid":true},"officeCode":{"String":"2","Valid":true},"reportsTo":{"Int64":1143,"Valid":true},"jobTitle":{"String":"Sales Rep","Valid":true}}]}%