diff --git a/Formula/kapacitor.rb b/Formula/kapacitor.rb
index 056d7bd2e3ef..f4ad96c02939 100644
--- a/Formula/kapacitor.rb
+++ b/Formula/kapacitor.rb
@@ -22,6 +22,10 @@ class Kapacitor < Formula
   depends_on "go" => :build
   depends_on "rust" => :build
 
+  on_linux do
+    depends_on "pkg-config" => :build # for `pkg-config-wrapper`
+  end
+
   # NOTE: The version here is specified in the go.mod of kapacitor.
   # If you're upgrading to a newer kapacitor version, check to see if this needs upgraded too.
   resource "pkg-config-wrapper" do
@@ -29,12 +33,31 @@ class Kapacitor < Formula
     sha256 "9bfe2c06b09fe7f3274f4ff8da1d87c9102640285bb38dad9a8c26dd5b9fe5af"
   end
 
+  # Temporary resource using version specified in the go.mod of kapacitor.
+  # We currently need this to support building with Rust v1.54+.
+  # Upstream issue ref: https://github.com/influxdata/kapacitor/issues/2612
+  # TODO: Remove when `flux` version in go.mod is updated to v0.124 or later.
+  resource "flux" do
+    url "https://github.com/influxdata/flux/archive/4347b978c91a46349790f773239589ba6abdfd98.tar.gz"
+    sha256 "557cf85a756a633dacb08852ee55889c246df412330119bd844612d2cc55ce23"
+    version "0.116.1-0.20210519190248-4347b978c91a"
+
+    # Fix build with Rust v1.54+.
+    # Backport of https://github.com/influxdata/flux/commit/c29d2c02ab42d591bb91e5d6321dacba3609e928
+    patch :DATA
+  end
+
   def install
     resource("pkg-config-wrapper").stage do
       system "go", "build", *std_go_args, "-o", buildpath/"bootstrap/pkg-config"
     end
     ENV.prepend_path "PATH", buildpath/"bootstrap"
 
+    # Fix build with Rust v1.54+. Remove when flux in go.mod is updated to v0.124+.
+    r = resource("flux")
+    (buildpath/"flux").install r
+    system "go", "mod", "edit", "-replace", "github.com/influxdata/flux@v#{r.version}=#{buildpath}/flux"
+
     ldflags = %W[
       -s
       -w
@@ -115,3 +138,69 @@ def plist
     end
   end
 end
+
+__END__
+diff --git a/libflux/flux-core/src/parser/mod.rs b/libflux/flux-core/src/parser/mod.rs
+index c35771a6..6430654c 100644
+--- a/libflux/flux-core/src/parser/mod.rs
++++ b/libflux/flux-core/src/parser/mod.rs
+@@ -32,7 +32,6 @@ pub fn parse_string(name: &str, s: &str) -> File {
+ }
+ 
+ struct TokenError {
+-    pub message: String,
+     pub token: Token,
+ }
+ 
+@@ -1398,7 +1397,7 @@ impl Parser {
+                                 value,
+                             }));
+                         }
+-                        Err(message) => return Err(TokenError { token: t, message }),
++                        Err(_) => return Err(TokenError { token: t }),
+                     }
+                 }
+                 TokenType::StringExpr => {
+@@ -1473,10 +1472,7 @@ impl Parser {
+                 base: self.base_node_from_token(&t),
+                 value,
+             }),
+-            Err(_) => Err(TokenError {
+-                token: t,
+-                message: String::from("failed to parse float literal"),
+-            }),
++            Err(_) => Err(TokenError { token: t }),
+         }
+     }
+     fn parse_string_literal(&mut self) -> StringLit {
+@@ -1520,7 +1516,7 @@ impl Parser {
+                 base: self.base_node_from_token(&t),
+                 value,
+             }),
+-            Err(message) => Err(TokenError { token: t, message }),
++            Err(_message) => Err(TokenError { token: t }),
+         }
+     }
+     fn parse_duration_literal(&mut self) -> Result<DurationLit, TokenError> {
+@@ -1532,7 +1528,7 @@ impl Parser {
+                 base: self.base_node_from_token(&t),
+                 values,
+             }),
+-            Err(message) => Err(TokenError { token: t, message }),
++            Err(_message) => Err(TokenError { token: t }),
+         }
+     }
+     fn parse_pipe_literal(&mut self) -> PipeLit {
+diff --git a/libflux/go/libflux/buildinfo.gen.go b/libflux/go/libflux/buildinfo.gen.go
+index 104cb0c9..d1223a3a 100644
+--- a/libflux/go/libflux/buildinfo.gen.go
++++ b/libflux/go/libflux/buildinfo.gen.go
+@@ -29,7 +29,7 @@ var sourceHashes = map[string]string{
+ 	"libflux/flux-core/src/formatter/mod.rs":                                        "de2216b303b3a57627bae6eb7788e7b7ecc5ef5638242380533e9efdea7e512e",
+ 	"libflux/flux-core/src/formatter/tests.rs":                                      "e6bd0be3341673a6c2b5d45ebefcdf6f74c7608eea7f45410aff43c66f1916b8",
+ 	"libflux/flux-core/src/lib.rs":                                                  "49b07452edaed71ccfdb850c3ae1b7d8903f4e4837ae601d300edab19b34004c",
+-	"libflux/flux-core/src/parser/mod.rs":                                           "31b69ead574a94a5652b25be1d134bd48a4b342603c6a6f72f46726520ca5b3c",
++	"libflux/flux-core/src/parser/mod.rs":                                           "221cc327e434573ca27b46864ea3b53f151f1491dfca2dcd7af06b27ac0bda10",
+ 	"libflux/flux-core/src/parser/strconv.rs":                                       "748c82f6efc2eafaafb872db5b4185ce29aafa8f03ba02c4b84f4a9614e832d2",
+ 	"libflux/flux-core/src/parser/tests.rs":                                         "e3a7c9222f90323a7ea9b319bd84f96f66c6f115af6d199a0da332c894713ae4",
+ 	"libflux/flux-core/src/scanner/mod.rs":                                          "2e15c9e0a73d0936d2eaeec030b636786db6dbe7aab673045de3a3e815c49f8a",