How can I `encode_base64` string in lua in nginx?-CodePudding

I am using lua inside nginx, below is the code to encode a string:

set_by_lua $base64_credential '
              set $es_username os.getenv("ES_USERNAME");
              set $es_pwd os.getenv("ES_PWD");
              return ngx.encode_base64(ngx.var.es_username ":" ngx.var.es_pwd)
            '

after launching the server I got below error:

2021/11/18 01:58:01 [error] 7#7: *151 failed to load inlined Lua code: set_by_lua:2: '=' expected near '$', client: 10.0.6.61, server: localhost, request: "GET /health HTTP/1.1", host: "10.0.1.246:8080"

I use the syntax from this doc https://github.com/openresty/lua-nginx-module#set_by_lua and it doesn't use = sign when set a variable. What did I do wrong?

CodePudding user response：

Again, you made a couple of errors. Lua operator for string concatenation is ... Lua doesn't expect semicolons between the operators. You have a weird mix of lua and nginx configuration syntax. If you don't need those $es_username and $es_pwd variables elsewhere, use

set_by_lua $base64_credential '
    local es_username = os.getenv("ES_USERNAME")
    local es_pwd = os.getenv("ES_PWD")
    return ngx.encode_base64(es_username .. ":" .. es_pwd)
';

If you need those variables elsewhere, then your way is

set_by_lua $es_username       'return os.getenv("ES_USERNAME")';
set_by_lua $es_pwd            'return os.getenv("ES_PWD")';
set_by_lua $base64_credential 'return ngx.encode_base64(ngx.var.es_username .. ":" .. ngx.var.es_pwd)';