How to handle refresh tokens in golang/oauth2 client lib

You need not bother about refreshing tokens until the time you are storing the Expiry parameter. After getting the ‘Token’ object, store the following in your database:

token.AccessToken, token.RefreshToken, token.TokenType and token.Expiry

while fetching, construct the token object again using the above parameters:

token := new(oauth2.Token)
token.AccessToken = {{ From DataBase }}
token.RefreshToken = {{ From DataBase }}
token.Expiry = {{ From DataBase }}
token.TokenType = {{ From DataBase }}

and then get your http client:

config.Client(ctx, token)

this will handle refreshing the token. Excerpt (more info: Golang oauth2 client):

Client returns an HTTP client using the provided token. The token will auto-refresh as necessary.

Only downside is, the refreshed access token is not returned. But it works! Google has no restrictions on how many times the refresh token is used.