view src/http/ngx_http_postpone_filter_module.c @ 9202:e88cdaa0f1ff

AIO operations now add timers (ticket #2162). Each AIO (thread IO) operation being run is now accompanied with 1-minute timer. This timer prevents unexpected shutdown of the worker process while an AIO operation is running, and logs an alert if the operation is running for too long. This fixes "open socket left" alerts during worker processes shutdown due to pending AIO (or thread IO) operations while corresponding requests have no timers. In particular, such errors were observed while reading cache headers (ticket #2162), and with worker_shutdown_timeout.
author Maxim Dounin <mdounin@mdounin.ru>
date Mon, 29 Jan 2024 10:31:37 +0300
parents 43585e0e12a3
children
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/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_http.h>


static ngx_int_t ngx_http_postpone_filter_add(ngx_http_request_t *r,
    ngx_chain_t *in);
static ngx_int_t ngx_http_postpone_filter_in_memory(ngx_http_request_t *r,
    ngx_chain_t *in);
static ngx_int_t ngx_http_postpone_filter_init(ngx_conf_t *cf);


static ngx_http_module_t  ngx_http_postpone_filter_module_ctx = {
    NULL,                                  /* preconfiguration */
    ngx_http_postpone_filter_init,         /* postconfiguration */

    NULL,                                  /* create main configuration */
    NULL,                                  /* init main configuration */

    NULL,                                  /* create server configuration */
    NULL,                                  /* merge server configuration */

    NULL,                                  /* create location configuration */
    NULL                                   /* merge location configuration */
};


ngx_module_t  ngx_http_postpone_filter_module = {
    NGX_MODULE_V1,
    &ngx_http_postpone_filter_module_ctx,  /* module context */
    NULL,                                  /* module directives */
    NGX_HTTP_MODULE,                       /* module type */
    NULL,                                  /* init master */
    NULL,                                  /* init module */
    NULL,                                  /* init process */
    NULL,                                  /* init thread */
    NULL,                                  /* exit thread */
    NULL,                                  /* exit process */
    NULL,                                  /* exit master */
    NGX_MODULE_V1_PADDING
};


static ngx_http_output_body_filter_pt    ngx_http_next_body_filter;


static ngx_int_t
ngx_http_postpone_filter(ngx_http_request_t *r, ngx_chain_t *in)
{
    ngx_connection_t              *c;
    ngx_http_postponed_request_t  *pr;

    c = r->connection;

    ngx_log_debug3(NGX_LOG_DEBUG_HTTP, c->log, 0,
                   "http postpone filter \"%V?%V\" %p", &r->uri, &r->args, in);

    if (r->subrequest_in_memory) {
        return ngx_http_postpone_filter_in_memory(r, in);
    }

    if (r != c->data) {

        if (in) {
            if (ngx_http_postpone_filter_add(r, in) != NGX_OK) {
                return NGX_ERROR;
            }

            return NGX_OK;
        }

#if 0
        /* TODO: SSI may pass NULL */
        ngx_log_error(NGX_LOG_ALERT, c->log, 0,
                      "http postpone filter NULL inactive request");
#endif

        return NGX_OK;
    }

    if (r->postponed == NULL) {

        if (in || c->buffered) {
            return ngx_http_next_body_filter(r->main, in);
        }

        return NGX_OK;
    }

    if (in) {
        if (ngx_http_postpone_filter_add(r, in) != NGX_OK) {
            return NGX_ERROR;
        }
    }

    do {
        pr = r->postponed;

        if (pr->request) {

            ngx_log_debug2(NGX_LOG_DEBUG_HTTP, c->log, 0,
                           "http postpone filter wake \"%V?%V\"",
                           &pr->request->uri, &pr->request->args);

            r->postponed = pr->next;

            c->data = pr->request;

            return ngx_http_post_request(pr->request, NULL);
        }

        if (pr->out == NULL) {
            ngx_log_error(NGX_LOG_ALERT, c->log, 0,
                          "http postpone filter NULL output");

        } else {
            ngx_log_debug2(NGX_LOG_DEBUG_HTTP, c->log, 0,
                           "http postpone filter output \"%V?%V\"",
                           &r->uri, &r->args);

            if (ngx_http_next_body_filter(r->main, pr->out) == NGX_ERROR) {
                return NGX_ERROR;
            }
        }

        r->postponed = pr->next;

    } while (r->postponed);

    return NGX_OK;
}


static ngx_int_t
ngx_http_postpone_filter_add(ngx_http_request_t *r, ngx_chain_t *in)
{
    ngx_http_postponed_request_t  *pr, **ppr;

    if (r->postponed) {
        for (pr = r->postponed; pr->next; pr = pr->next) { /* void */ }

        if (pr->request == NULL) {
            goto found;
        }

        ppr = &pr->next;

    } else {
        ppr = &r->postponed;
    }

    pr = ngx_palloc(r->pool, sizeof(ngx_http_postponed_request_t));
    if (pr == NULL) {
        return NGX_ERROR;
    }

    *ppr = pr;

    pr->request = NULL;
    pr->out = NULL;
    pr->next = NULL;

found:

    if (ngx_chain_add_copy(r->pool, &pr->out, in) == NGX_OK) {
        return NGX_OK;
    }

    return NGX_ERROR;
}


static ngx_int_t
ngx_http_postpone_filter_in_memory(ngx_http_request_t *r, ngx_chain_t *in)
{
    size_t                     len;
    ngx_buf_t                 *b;
    ngx_connection_t          *c;
    ngx_http_core_loc_conf_t  *clcf;

    c = r->connection;

    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, c->log, 0,
                   "http postpone filter in memory");

    if (r->out == NULL) {
        clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);

        if (r->headers_out.content_length_n != -1) {
            len = r->headers_out.content_length_n;

            if (len > clcf->subrequest_output_buffer_size) {
                ngx_log_error(NGX_LOG_ERR, c->log, 0,
                              "too big subrequest response: %uz", len);
                return NGX_ERROR;
            }

        } else {
            len = clcf->subrequest_output_buffer_size;
        }

        b = ngx_create_temp_buf(r->pool, len);
        if (b == NULL) {
            return NGX_ERROR;
        }

        b->last_buf = 1;

        r->out = ngx_alloc_chain_link(r->pool);
        if (r->out == NULL) {
            return NGX_ERROR;
        }

        r->out->buf = b;
        r->out->next = NULL;
    }

    b = r->out->buf;

    for ( /* void */ ; in; in = in->next) {

        if (ngx_buf_special(in->buf)) {
            continue;
        }

        len = in->buf->last - in->buf->pos;

        if (len > (size_t) (b->end - b->last)) {
            ngx_log_error(NGX_LOG_ERR, c->log, 0,
                          "too big subrequest response");
            return NGX_ERROR;
        }

        ngx_log_debug1(NGX_LOG_DEBUG_HTTP, c->log, 0,
                       "http postpone filter in memory %uz bytes", len);

        b->last = ngx_cpymem(b->last, in->buf->pos, len);
        in->buf->pos = in->buf->last;
    }

    return NGX_OK;
}


static ngx_int_t
ngx_http_postpone_filter_init(ngx_conf_t *cf)
{
    ngx_http_next_body_filter = ngx_http_top_body_filter;
    ngx_http_top_body_filter = ngx_http_postpone_filter;

    return NGX_OK;
}