Why can not modify the value in nginx.conf

Klen

4/10/24, 3:20 AM

I have a map in nginx.conf,

stream {
    upstream s1{
        server 127.0.0.1:670;
    }
    upstream s2{
        server 127.0.0.1:680;
    }

    map $symbol_key $symbol_value{
        c1 s1;
        c2 s2;
    }
    server {
        set $symbol_key "c1";
        set $symbol_value "s1";
        listen 66;
        proxy_pass $symbol_value;
    }

}

If I delete map, the request can be routed to s2 after I set symbol_value to s2. But I want to decide router throw symbol_key, if I use the map, no matter which value(c1 or c2) I set to symbol_key, request will always be routed to s1.

I modify the value in phases[NGX_STREAM_PREREAD_PHASE].handlers like this

ngx_str_t str1 = ngx_string("symbol_key");
ngx_uint_t key = ngx_hash_key(str1.data, str1.len);
ngx_stream_variable_value_t *vv = ngx_stream_get_variable(s, &str1, key);
ngx_str_t str2 = ngx_string("c2");
vv->data = str2.data;
vv->len = str2.len;
ngx_log_error(NGX_LOG_ERR, c->log, 0, "after set");

Why can not the request be routed to s2?

0 + 0

nginx

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