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Posted to notifications@apisix.apache.org by GitBox <gi...@apache.org> on 2021/04/08 19:47:52 UTC
[GitHub] [apisix] diaosj opened a new issue #4010: request help: question about dns_resolver_valid and resolver_timeout
diaosj opened a new issue #4010:
URL: https://github.com/apache/apisix/issues/4010
### Issue description
Two questions about `dns_resolver_valid` and `resolver_timeout`.
1. What's the default unit?
In my memory, the default unit is second rather than millisecond. And I found this comment in config.yaml: https://github.com/apache/apisix/blob/master/conf/config-default.yaml#L111
I guess the description "The unit is second." is valid for both `dns_resolver_valid` and `resolver_timeout`?
And I found Nginx doc that says: "A value without a suffix means seconds. It is recommended to always specify a suffix."
http://nginx.org/en/docs/syntax.html
But the Nginx code here: https://github.com/nginx/nginx/blob/eb52de83114e8d98722cd17ec8435c47956b6315/src/http/ngx_http_core_module.c#L731-L733
`resolver_timeout` seems to be used with `ngx_conf_set_msec_slot`. "msec" here implies that unit is millisecond? I'm confused.
And I tried to set this param like this: `resolver_timeout: 5s`. But APISIX said it can only be assigned with a number. Haha.
2. In older versions, both `dns_resolver_valid` and `resolver_timeout` are enabled. Now only `resolver_timeout` is enabled in config.yaml. Curious about this change. ^_^
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[GitHub] [apisix] diaosj commented on issue #4010: request help: question about dns_resolver_valid and resolver_timeout
Posted by GitBox <gi...@apache.org>.
diaosj commented on issue #4010:
URL: https://github.com/apache/apisix/issues/4010#issuecomment-816353113
Many thanks.
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[GitHub] [apisix] diaosj commented on issue #4010: request help: question about dns_resolver_valid and resolver_timeout
Posted by GitBox <gi...@apache.org>.
diaosj commented on issue #4010:
URL: https://github.com/apache/apisix/issues/4010#issuecomment-816426176
OK. Thanks!
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[GitHub] [apisix] diaosj commented on issue #4010: request help: question about dns_resolver_valid and resolver_timeout
Posted by GitBox <gi...@apache.org>.
diaosj commented on issue #4010:
URL: https://github.com/apache/apisix/issues/4010#issuecomment-816365499
> > What's the default unit?
>
> `ngx_conf_set_msec_slot` calls `ngx_parse_time`, in such a case, when the time doesn't contain the unit, nginx treats it a duration in seconds.
>
Sorry, I reopen this issue.
Just to make sure.
I see `ngx_parse_time` is called in `ngx_conf_set_msec_slot` (https://github.com/nginx/nginx/blob/eb52de83114e8d98722cd17ec8435c47956b6315/src/core/ngx_conf_file.c#L1276):
```c
*msp = ngx_parse_time(&value[1], 0);
```
I jumped to the definition of `ngx_parse_time` (https://github.com/nginx/nginx/blob/eb52de83114e8d98722cd17ec8435c47956b6315/src/core/ngx_parse.c#L112):
```c
ngx_int_t
ngx_parse_time(ngx_str_t *line, ngx_uint_t is_sec)Ruslan Ermilov, 10 years ago: • Improved ngx_parse_time() code readability.
{
u_char *p, *last;
ngx_int_t value, total, scale;
ngx_int_t max, cutoff, cutlim;
ngx_uint_t valid;
enum {
st_start = 0,
st_year,
st_month,
st_week,
st_day,
st_hour,
st_min,
st_sec,
st_msec,
st_last
} step;
valid = 0;
value = 0;
total = 0;
cutoff = NGX_MAX_INT_T_VALUE / 10;
cutlim = NGX_MAX_INT_T_VALUE % 10;
step = is_sec ? st_start : st_month;
p = line->data;
last = p + line->len;
while (p < last) {
if (*p >= '0' && *p <= '9') {
if (value >= cutoff && (value > cutoff || *p - '0' > cutlim)) {
return NGX_ERROR;
}
value = value * 10 + (*p++ - '0');
valid = 1;
continue;
}
switch (*p++) {
case 'y':
if (step > st_start) {
return NGX_ERROR;
}
step = st_year;
max = NGX_MAX_INT_T_VALUE / (60 * 60 * 24 * 365);
scale = 60 * 60 * 24 * 365;
break;
case 'M':
if (step >= st_month) {
return NGX_ERROR;
}
step = st_month;
max = NGX_MAX_INT_T_VALUE / (60 * 60 * 24 * 30);
scale = 60 * 60 * 24 * 30;
break;
case 'w':
if (step >= st_week) {
return NGX_ERROR;
}
step = st_week;
max = NGX_MAX_INT_T_VALUE / (60 * 60 * 24 * 7);
scale = 60 * 60 * 24 * 7;
break;
case 'd':
if (step >= st_day) {
return NGX_ERROR;
}
step = st_day;
max = NGX_MAX_INT_T_VALUE / (60 * 60 * 24);
scale = 60 * 60 * 24;
break;
case 'h':
if (step >= st_hour) {
return NGX_ERROR;
}
step = st_hour;
max = NGX_MAX_INT_T_VALUE / (60 * 60);
scale = 60 * 60;
break;
case 'm':
if (p < last && *p == 's') {
if (is_sec || step >= st_msec) {
return NGX_ERROR;
}
p++;
step = st_msec;
max = NGX_MAX_INT_T_VALUE;
scale = 1;
break;
}
if (step >= st_min) {
return NGX_ERROR;
}
step = st_min;
max = NGX_MAX_INT_T_VALUE / 60;
scale = 60;
break;
case 's':
if (step >= st_sec) {
return NGX_ERROR;
}
step = st_sec;
max = NGX_MAX_INT_T_VALUE;
scale = 1;
break;
case ' ':
if (step >= st_sec) {
return NGX_ERROR;
}
step = st_last;
max = NGX_MAX_INT_T_VALUE;
scale = 1;
break;
default:
return NGX_ERROR;
}
if (step != st_msec && !is_sec) {
scale *= 1000;
max /= 1000;
}
if (value > max) {
return NGX_ERROR;
}
value *= scale;
if (total > NGX_MAX_INT_T_VALUE - value) {
return NGX_ERROR;
}
total += value;
value = 0;
while (p < last && *p == ' ') {
p++;
}
}
if (!valid) {
return NGX_ERROR;
}
if (!is_sec) {
if (value > NGX_MAX_INT_T_VALUE / 1000) {
return NGX_ERROR;
}
value *= 1000;
}
if (total > NGX_MAX_INT_T_VALUE - value) {
return NGX_ERROR;
}
return total + value;
}
```
The input param `is_sec` is 0. So the variable `step` in L136 is assigned to `st_month`.
```c
step = is_sec ? st_start : st_month;
```
Seems like to go to `case ' ':` branch. Then the variable `step` in L233 is assigned to `st_last`.
```c
step = st_last;
```
Then the `if (step != st_msec && !is_sec)` branch in L242 makes `scale` to 1000 timed.
```c
scale *= 1000;
```
Is this what you said, "nginx treats it a duration in seconds"?
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[GitHub] [apisix] diaosj closed issue #4010: request help: question about dns_resolver_valid and resolver_timeout
Posted by GitBox <gi...@apache.org>.
diaosj closed issue #4010:
URL: https://github.com/apache/apisix/issues/4010
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[GitHub] [apisix] tokers commented on issue #4010: request help: question about dns_resolver_valid and resolver_timeout
Posted by GitBox <gi...@apache.org>.
tokers commented on issue #4010:
URL: https://github.com/apache/apisix/issues/4010#issuecomment-816338481
> What's the default unit?
`ngx_conf_set_msec_slot` calls `ngx_parse_time`, in such a case, when the time doesn't contain the unit, nginx treats it a duration in seconds.
> In older versions, both dns_resolver_valid and resolver_timeout are enabled. Now only resolver_timeout is enabled in config.yaml. Curious about this change. ^_^
Now by default we use the ttl field in the DNS response as the cache ttl.
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[GitHub] [apisix] tokers commented on issue #4010: request help: question about dns_resolver_valid and resolver_timeout
Posted by GitBox <gi...@apache.org>.
tokers commented on issue #4010:
URL: https://github.com/apache/apisix/issues/4010#issuecomment-816412900
Variable `step` doesn't have a chance to be used since all chars in `line` is digital.
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[GitHub] [apisix] diaosj closed issue #4010: request help: question about dns_resolver_valid and resolver_timeout
Posted by GitBox <gi...@apache.org>.
diaosj closed issue #4010:
URL: https://github.com/apache/apisix/issues/4010
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