Redirect when coming header- http_cookie: TOOLDSITE to another container

[allanian]

Hello, how i can redirect to another container, when getting location path contained "api_v2", "api_v3" ?
Trying with redirect to application with proxy, but its not supported

      "routes": {
        "phpapp": [
          {
            "match": {
              "uri": ["*api_v2*", "*api_v3*"]
            },
            "action": {
              "pass": "applications/phpapp/old"
            }
          }
       ]

      "applications": {
        "phpapp": {
          "type": "php",
          "targets": {
            "old": {
               "proxy": "http://old.phpapp-prod.svc:8080"
            }
          }
        }
      }

[lcrilly]

You can use the proxy action directly in the route. It doesn't need the application object.

[allanian]

Hm, yes, but how i can use dns name in proxy section, with ip its worknig nice?
I have 2 containers in one namespace and need proxy to a second container when getting path contained api_v2

      "routes": {
        "phpapp": [
          {
            "match": {
              "uri": ["*api_v2*", "*api_v3*"]
            },
            "action": {
              "proxy": "http://old.phpapp-prod.svc:8080"
            }
          }
       ]

[lcrilly]

Unit doesn't support DNS hostname for proxying.

you can use UNIX, IPv4, and IPv6 socket addresses for proxy destinations.

You might consider co-locating the v2, v3 and "old" applications in the same Unit container and just routing between them? You'll be doing the same amount of work as before, so it's not a scaling problem. And with Unit you don't have to worry about having multiple services in the same container.

[ac000]

You could try this rough and ready PoC patch. The main caveats are

1. It will just use the first IP address as returned by getaddrinfo(3)
2. The DNS lookup is done at configure time so if the IP address changes...

diff --git a/src/nxt_sockaddr.c b/src/nxt_sockaddr.c
index 32941893..2f729532 100644
--- a/src/nxt_sockaddr.c
+++ b/src/nxt_sockaddr.c
@@ -2,20 +2,24 @@
 /*
  * Copyright (C) Igor Sysoev
  * Copyright (C) NGINX, Inc.
  */
 
+#include <stdbool.h>
+#include <arpa/inet.h>
+
 #include <nxt_main.h>
 
 
 #if (NXT_INET6)
 static u_char *nxt_inet6_ntop(u_char *addr, u_char *buf, u_char *end);
 #endif
 
 static nxt_sockaddr_t *nxt_sockaddr_unix_parse(nxt_mp_t *mp, nxt_str_t *addr);
 static nxt_sockaddr_t *nxt_sockaddr_inet6_parse(nxt_mp_t *mp, nxt_str_t *addr);
 static nxt_sockaddr_t *nxt_sockaddr_inet_parse(nxt_mp_t *mp, nxt_str_t *addr);
+static nxt_sockaddr_t *nxt_sockaddr_host_parse(nxt_mp_t *mp, nxt_str_t *addr);
 
 
 nxt_sockaddr_t *
 nxt_sockaddr_cache_alloc(nxt_event_engine_t *engine, nxt_listen_socket_t *ls)
 {
@@ -538,10 +542,24 @@ nxt_sockaddr_parse(nxt_mp_t *mp, nxt_str_t *addr)
 
     return sa;
 }
 
 
+static inline bool is_hostname(const u_char *str)
+{
+    while (*str) {
+        if ((*str != '.' && *str != ':') && (*str < '0' || *str > '9')) {
+            return true;
+        }
+
+        str++;
+    }
+
+    return false;
+}
+
+
 nxt_sockaddr_t *
 nxt_sockaddr_parse_optport(nxt_mp_t *mp, nxt_str_t *addr)
 {
     nxt_sockaddr_t  *sa;
 
@@ -554,12 +572,15 @@ nxt_sockaddr_parse_optport(nxt_mp_t *mp, nxt_str_t *addr)
         sa = nxt_sockaddr_unix_parse(mp, addr);
 
     } else if (addr->start[0] == '[' || nxt_inet6_probe(addr)) {
         sa = nxt_sockaddr_inet6_parse(mp, addr);
 
-    } else {
+    } else if (!is_hostname(addr->start)) {
         sa = nxt_sockaddr_inet_parse(mp, addr);
+
+    } else {
+        sa = nxt_sockaddr_host_parse(mp, addr);
     }
 
     if (nxt_fast_path(sa != NULL)) {
         nxt_sockaddr_text(sa);
     }
@@ -768,10 +789,69 @@ nxt_sockaddr_inet_parse(nxt_mp_t *mp, nxt_str_t *addr)
 
     return sa;
 }
 
 
+static nxt_sockaddr_t *
+nxt_sockaddr_host_parse(nxt_mp_t *mp, nxt_str_t *addr)
+{
+    int              err;
+    char             ipaddr[NXT_INET6_ADDR_STR_LEN];
+    char             ipport[NXT_INET6_ADDR_STR_LEN + 8];
+    char             *host, *p;
+    nxt_str_t        str;
+    nxt_sockaddr_t   *sa;
+    struct addrinfo  *res;
+
+    host = strndup((char *)addr->start, addr->length);
+    p = memchr(host, ':', strlen(host));
+    if (p != NULL) {
+        *p = '\0';
+
+        if (strlen(p + 1) > 5) {
+            nxt_thread_log_error(NXT_LOG_ERR, "invalid port in \"%V\"", addr);
+            goto out_free;
+        }
+    }
+
+    err = getaddrinfo(host, NULL, NULL, &res);
+    if (err) {
+        goto out_free;
+    }
+
+    if (res->ai_family == AF_INET) {
+        inet_ntop(AF_INET, &((struct sockaddr_in *)res->ai_addr)->sin_addr,
+                  ipaddr, NXT_INET6_ADDR_STR_LEN);
+
+        sprintf(ipport, "%s%s%s", ipaddr, p ? ":" : "", p ? p + 1 : "");
+
+        /* Do this manually as nxt_length() is using sizeof(ipport) */
+        str.start = (u_char *)ipport;
+        str.length = strlen(ipport);
+        sa = nxt_sockaddr_inet_parse(mp, &str);
+#if (NXT_INET6)
+    } else {
+        inet_ntop(AF_INET6, &((struct sockaddr_in6 *)res->ai_addr)->sin6_addr,
+                  ipaddr, NXT_INET6_ADDR_STR_LEN);
+
+        sprintf(ipport, "[%s]%s%s", ipaddr, p ? ":" : "", p ? p + 1 : "");
+
+        str.start = (u_char *)ipport;
+        str.length = strlen(ipport);
+        sa = nxt_sockaddr_inet6_parse(mp, &str);
+#endif
+    }
+
+    freeaddrinfo(res);
+
+out_free:
+    free(host);
+
+    return sa;
+}
+
+
 in_addr_t
 nxt_inet_addr(u_char *buf, size_t length)
 {
     u_char      c, *end;
     in_addr_t   addr;

[hongzhidao]

I'd like to add the following, it's a topic of DNS resolver.

1. getaddrinfo() is a block call, it might make the reconfiguration slow.
2. The optinal way is to introduce a native async DNS client, but it requires lots of work and we need to specify a DNS server in the configuration like "resolver": "...".
3. The result from getaddrinfo() needs to behave like a round-robin upstream.

[ac000]

1 Obviously if you want to use a hostname then you need functioning DNS...

2 Seems totally overkill for this.

3 Yes see caveats.

Anyway it was just a quick hack to show what the minimal thing, that would likely work most of the time, would look like.

[hongzhidao]

Yes, good experiment and it needs more work based on it to be a production code.

[allanian]

thx a lot!