use recommended nginx patch

nixbld-etc-nixos/configuration.nix

@@ -215,18 +215,6 @@ ACTION=="add", SUBSYSTEM=="tty", \
   };
  
   nixpkgs.config.packageOverrides = super: let self = super.pkgs; in {
-    # nginx etag patch merged in Nixpkgs 19.09, remove after upgrading
-    # https://github.com/NixOS/nixpkgs/pull/60578
-    nginx = super.nginx.overrideAttrs(oa: {
-      patches = oa.patches ++ [
-        (super.substituteAll {
-          src = ./nix-etag-1.15.4.patch;
-          preInstall = ''
-            export nixStoreDir="$NIX_STORE" nixStoreDirLen="''${#NIX_STORE}"
-          '';
-        })
-      ];
-    });
     hydra = super.hydra.overrideAttrs(oa: {
       patches = oa.patches ++ [ ./hydra-conda.patch ./hydra-retry.patch ];
       hydraPath = oa.hydraPath + ":" + super.lib.makeBinPath [ super.jq ];
@@ -390,6 +378,19 @@ ACTION=="add", SUBSYSTEM=="tty", \
       };
     };
   };
+  # not needed after 19.09 - https://github.com/NixOS/nixpkgs/pull/60578
+  services.nginx.package = pkgs.nginx.overrideAttrs (drv: {
+    patches = (drv.patches or []) ++ pkgs.lib.singleton (pkgs.fetchurl {
+      url = "https://raw.githubusercontent.com/NixOS/nixpkgs/master/"
+          + "pkgs/servers/http/nginx/nix-etag-1.15.4.patch";
+      sha256 = "0i2lfz66204kcm1qdqws07cbq5nh1grxcz1ycp6qhmypl3da8hq4";
+      postFetch = ''
+        substituteInPlace "$out" \
+          --subst-var-by nixStoreDir "$NIX_STORE" \
+          --subst-var-by nixStoreDirLen "''${#NIX_STORE}"
+      '';
+    });
+  });
   services.uwsgi = {
     enable = true;
     plugins = [ "python3" ];

nixbld-etc-nixos/nix-etag-1.15.4.patch

@@ -1,92 +0,0 @@
-From f6a978f024d01202f954483423af1b2d5d5159a6 Mon Sep 17 00:00:00 2001
-From: Yegor Timoshenko <yegortimoshenko@riseup.net>
-Date: Fri, 28 Sep 2018 03:27:04 +0000
-Subject: [PATCH] If root is in Nix store, set ETag to its path hash
-
----
- src/http/ngx_http_core_module.c | 56 +++++++++++++++++++++++++++++----
- 1 file changed, 50 insertions(+), 6 deletions(-)
-
-diff --git a/src/http/ngx_http_core_module.c b/src/http/ngx_http_core_module.c
-index c57ec00c..b7992de2 100644
---- a/src/http/ngx_http_core_module.c
-+++ b/src/http/ngx_http_core_module.c
-@@ -1583,6 +1583,7 @@ ngx_http_set_etag(ngx_http_request_t *r)
- {
-     ngx_table_elt_t           *etag;
-     ngx_http_core_loc_conf_t  *clcf;
-+    u_char                    *real, *ptr1, *ptr2;
- 
-     clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);
- 
-@@ -1598,16 +1599,61 @@ ngx_http_set_etag(ngx_http_request_t *r)
-     etag->hash = 1;
-     ngx_str_set(&etag->key, "ETag");
- 
--    etag->value.data = ngx_pnalloc(r->pool, NGX_OFF_T_LEN + NGX_TIME_T_LEN + 3);
--    if (etag->value.data == NULL) {
-+    real = ngx_realpath(clcf->root.data, NULL);
-+
-+    if (real == NULL) {
-         etag->hash = 0;
-         return NGX_ERROR;
-     }
- 
--    etag->value.len = ngx_sprintf(etag->value.data, "\"%xT-%xO\"",
--                                  r->headers_out.last_modified_time,
--                                  r->headers_out.content_length_n)
--                      - etag->value.data;
-+    #define NIX_STORE_DIR "@nixStoreDir@"
-+    #define NIX_STORE_LEN @nixStoreDirLen@
-+
-+    if (r->headers_out.last_modified_time == 1
-+        && !ngx_strncmp(real, NIX_STORE_DIR, NIX_STORE_LEN)
-+        && real[NIX_STORE_LEN] == '/'
-+        && real[NIX_STORE_LEN + 1] != '\0')
-+    {
-+        ptr1 = real + NIX_STORE_LEN;
-+        *ptr1 = '"';
-+
-+        ptr2 = (u_char *) ngx_strchr(ptr1, '-');
-+
-+        if (ptr2 == NULL) {
-+            ngx_free(real);
-+            etag->hash = 0;
-+            return NGX_ERROR;
-+        }
-+
-+        *ptr2++ = '"';
-+        *ptr2 = '\0';
-+
-+        etag->value.len = ngx_strlen(ptr1);
-+        etag->value.data = ngx_pnalloc(r->pool, etag->value.len);
-+
-+        if (etag->value.data == NULL) {
-+            ngx_free(real);
-+            etag->hash = 0;
-+            return NGX_ERROR;
-+        }
-+
-+        ngx_memcpy(etag->value.data, ptr1, etag->value.len);
-+    } else {
-+        etag->value.data = ngx_pnalloc(r->pool, NGX_OFF_T_LEN + NGX_TIME_T_LEN + 3);
-+
-+        if (etag->value.data == NULL) {
-+            ngx_free(real);
-+            etag->hash = 0;
-+            return NGX_ERROR;
-+        }
-+
-+        etag->value.len = ngx_sprintf(etag->value.data, "\"%xT-%xO\"",
-+                                      r->headers_out.last_modified_time,
-+                                      r->headers_out.content_length_n)
-+                          - etag->value.data;
-+    }
-+
-+    ngx_free(real);
- 
-     r->headers_out.etag = etag;
- 
--- 
-2.19.0
-