Deploy serverless functions to digitalocean in golang - go

Question

I am trying to build a CRUD in digital ocean serverless functions. I am testing with sqlite3 and insert into the table. When I tried to deploy it to productions, I am getting errors. Here is my code:
package main
import (
"database/sql"
"fmt"
_ "github.com/mattn/go-sqlite3"
)
func Main(args map[string]interface{}) map[string]interface{} {
db, err := sql.Open("sqlite3", "./data.db")
checkErr(err)
// insert
stmt, err := db.Prepare("INSERT INTO userinfo(username, departname, created) values(?,?,?)")
checkErr(err)
res, err := stmt.Exec("rumi", "CSE", "2012-12-09")
checkErr(err)
id, err := res.LastInsertId()
checkErr(err)
fmt.Println(id)
db.Close()
msg := make(map[string]interface{})
msg["body"] = id
return msg
}
Errors I am getting:
➜ functions git:(master) ✗ doctl serverless deploy . --remote-build
Deploying '/home/rumi/go/src/github.com/manjurulhoque/digitalocean-cloud-functions/functions'
to namespace 'fn-b799454253a-a40440-4639-937f-05102a48c06e'
on host 'https://fa45as-sgp1-18b45c02afgc.doserverless.co'
Submitted action 'blog/createBlog' for remote building and deployment in runtime go:default (id: b3d5421ee5656bb44c4295421eebb44c642cf)
Submitted action 'sample/hello' for remote building and deployment in runtime go:default (id: b3d5421ee5656bb44c4295421eebb44c642cf)
Submitted action 'blog/db' for remote building and deployment in runtime go:default (id: edcc9eefce9f4aa58c9eefce9f2aa5e6)
Transcript of remote build session for action 'blog/db':
Output of failed build in /tmp/slices/builds/fn-b79956253a-a4080-465639-95637f-05102a48c06e/blog_db/2022-10-22T04-23-08.642Z/packages/blog/db
initializing modules
go: creating new go.mod: module exec
go: to add module requirements and sums:
go mod tidy
building
db.go:6:2: no required module provides package github.com/mattn/go-sqlite3; to add it:
go get github.com/mattn/go-sqlite3
Deployed functions ('doctl sbx fn get <funcName> --url' for URL):
- blog/createBlog
- sample/hello
Failures:
Error: While deploying action 'blog/db': './build.sh' exited with code 1
project.yml
environment: {}
parameters: {}
packages:
- name: blog
environment: {}
parameters: {}
annotations: {}
functions:
- name: db
binary: false
main: ''
runtime: 'go:default'
web: true
parameters: {}
environment: {}
annotations: {}
limits: {}
I didn't find any good resource though to connect to DB. Any help would be appreciated.

Answer 1

In DO, every function itself is an app. So you need to create go.mod and go.sum in each function directoy.
Below is one of my project structure
Note: I wrote an article on how to setup golang app for DO
https://medium.com/#manzurulhoque/use-package-in-digital-ocean-do-serverless-functions-using-golang-cb5200ab22ee