Merge pull request #305 from squat/pprof

Pprof

cmd/kg/main.go

@@ -27,10 +27,10 @@ import (
 
 	"github.com/go-kit/kit/log"
 	"github.com/go-kit/kit/log/level"
+	"github.com/metalmatze/signal/internalserver"
 	"github.com/oklog/run"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/collectors"
-	"github.com/prometheus/client_golang/prometheus/promhttp"
 	"github.com/spf13/cobra"
 	apiextensions "k8s.io/apiextensions-apiserver/pkg/client/clientset/clientset"
 	"k8s.io/client-go/kubernetes"
@@ -251,18 +251,21 @@ func runRoot(_ *cobra.Command, _ []string) error {
 
 	var g run.Group
 	{
+		h := internalserver.NewHandler(
+			internalserver.WithName("Internal Kilo API"),
+			internalserver.WithPrometheusRegistry(registry),
+			internalserver.WithPProf(),
+		)
+		h.AddEndpoint("/health", "Exposes health checks", healthHandler)
+		h.AddEndpoint("/graph", "Exposes Kilo mesh topology graph", (&graphHandler{m, gr, &hostname, s}).ServeHTTP)
 		// Run the HTTP server.
-		mux := http.NewServeMux()
-		mux.HandleFunc("/health", healthHandler)
-		mux.Handle("/graph", &graphHandler{m, gr, &hostname, s})
-		mux.Handle("/metrics", promhttp.HandlerFor(registry, promhttp.HandlerOpts{}))
 		l, err := net.Listen("tcp", listen)
 		if err != nil {
 			return fmt.Errorf("failed to listen on %s: %v", listen, err)
 		}
 
 		g.Add(func() error {
-			if err := http.Serve(l, mux); err != nil && err != http.ErrServerClosed {
+			if err := http.Serve(l, h); err != nil && err != http.ErrServerClosed {
 				return fmt.Errorf("error: server exited unexpectedly: %v", err)
 			}
 			return nil

go.mod

@@ -10,6 +10,7 @@ require (
 	github.com/coreos/go-iptables v0.6.0
 	github.com/go-kit/kit v0.9.0
 	github.com/kylelemons/godebug v0.0.0-20170820004349-d65d576e9348
+	github.com/metalmatze/signal v0.0.0-20210307161603-1c9aa721a97a
 	github.com/oklog/run v1.1.0
 	github.com/prometheus/client_golang v1.11.0
 	github.com/spf13/cobra v1.1.3

go.sum

@@ -32,6 +32,8 @@ github.com/Azure/go-autorest/logger v0.2.0/go.mod h1:T9E3cAhj2VqvPOtCYAvby9aBXkZ
 github.com/Azure/go-autorest/tracing v0.6.0/go.mod h1:+vhtPC754Xsa23ID7GlGsrdKBpUA79WCAKPPZVC2DeU=
 github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
 github.com/BurntSushi/xgb v0.0.0-20160522181843-27f122750802/go.mod h1:IVnqGOEym/WlBOVXweHU+Q+/VP0lqqI8lqeDx9IjBqo=
+github.com/DATA-DOG/go-sqlmock v1.4.1 h1:ThlnYciV1iM/V0OSF/dtkqWb6xo5qITT1TJBG1MRDJM=
+github.com/DATA-DOG/go-sqlmock v1.4.1/go.mod h1:f/Ixk793poVmq4qj/V1dPUg2JEAKC73Q5eFN3EC/SaM=
 github.com/NYTimes/gziphandler v0.0.0-20170623195520-56545f4a5d46/go.mod h1:3wb06e3pkSAbeQ52E9H9iFoQsEEwGN64994WTCIhntQ=
 github.com/NYTimes/gziphandler v1.1.1/go.mod h1:n/CVRwUEOgIxrgPvAQhUUr9oeUtvrhMomdKFjzJNB0c=
 github.com/OneOfOne/xxhash v1.2.2/go.mod h1:HSdplMjZKSmBqAxg5vPj2TmRDmfkzw+cTzAElWljhcU=
@@ -253,6 +255,7 @@ github.com/jsimonetti/rtnetlink v0.0.0-20210525051524-4cc836578190 h1:iycCSDo8EK
 github.com/jsimonetti/rtnetlink v0.0.0-20210525051524-4cc836578190/go.mod h1:NmKSdU4VGSiv1bMsdqNALI4RSvvjtz65tTMCnD05qLo=
 github.com/json-iterator/go v1.1.6/go.mod h1:+SdeFBvtyEkXs7REEP0seUULqWtbJapLOCVDaaPEHmU=
 github.com/json-iterator/go v1.1.7/go.mod h1:KdQUCv79m/52Kvf8AW2vK1V8akMuk1QjK/uOdHXbAo4=
+github.com/json-iterator/go v1.1.9/go.mod h1:KdQUCv79m/52Kvf8AW2vK1V8akMuk1QjK/uOdHXbAo4=
 github.com/json-iterator/go v1.1.10/go.mod h1:KdQUCv79m/52Kvf8AW2vK1V8akMuk1QjK/uOdHXbAo4=
 github.com/json-iterator/go v1.1.11 h1:uVUAXhF2To8cbw/3xN3pxj6kk7TYKs98NIrTqPlMWAQ=
 github.com/json-iterator/go v1.1.11/go.mod h1:KdQUCv79m/52Kvf8AW2vK1V8akMuk1QjK/uOdHXbAo4=
@@ -310,6 +313,8 @@ github.com/mdlayher/netlink v1.4.1/go.mod h1:e4/KuJ+s8UhfUpO9z00/fDZZmhSrs+oxyqA
 github.com/mdlayher/socket v0.0.0-20210307095302-262dc9984e00/go.mod h1:GAFlyu4/XV68LkQKYzKhIo/WW7j3Zi0YRAz/BOoanUc=
 github.com/mdlayher/socket v0.0.0-20211102153432-57e3fa563ecb h1:2dC7L10LmTqlyMVzFJ00qM25lqESg9Z4u3GuEXN5iHY=
 github.com/mdlayher/socket v0.0.0-20211102153432-57e3fa563ecb/go.mod h1:nFZ1EtZYK8Gi/k6QNu7z7CgO20i/4ExeQswwWuPmG/g=
+github.com/metalmatze/signal v0.0.0-20210307161603-1c9aa721a97a h1:0usWxe5SGXKQovz3p+BiQ81Jy845xSMu2CWKuXsXuUM=
+github.com/metalmatze/signal v0.0.0-20210307161603-1c9aa721a97a/go.mod h1:3OETvrxfELvGsU2RoGGWercfeZ4bCL3+SOwzIWtJH/Q=
 github.com/miekg/dns v1.0.14/go.mod h1:W1PPwlIAgtquWBMBEV9nkV9Cazfe8ScdGz/Lj7v3Nrg=
 github.com/mikioh/ipaddr v0.0.0-20190404000644-d465c8ab6721 h1:RlZweED6sbSArvlE924+mUcZuXKLBHA35U7LN621Bws=
 github.com/mikioh/ipaddr v0.0.0-20190404000644-d465c8ab6721/go.mod h1:Ickgr2WtCLZ2MDGd4Gr0geeCH5HybhRJbonOgQpvSxc=
@@ -371,6 +376,7 @@ github.com/pquerna/cachecontrol v0.0.0-20171018203845-0dec1b30a021/go.mod h1:prY
 github.com/prometheus/client_golang v0.9.1/go.mod h1:7SWBe2y4D6OKWSNQJUaRYU/AaXPKyh/dDVn+NZz0KFw=
 github.com/prometheus/client_golang v0.9.3/go.mod h1:/TN21ttK/J9q6uSwhBd54HahCDft0ttaMvbicHlPoso=
 github.com/prometheus/client_golang v1.0.0/go.mod h1:db9x61etRT2tGnBNRi70OPL5FsnadC4Ky3P0J6CfImo=
+github.com/prometheus/client_golang v1.5.1/go.mod h1:e9GMxYsXl05ICDXkRhurwBS4Q3OK1iX/F2sw+iXX5zU=
 github.com/prometheus/client_golang v1.7.1/go.mod h1:PY5Wy2awLA44sXw4AOSfFBetzPP4j5+D6mVACh+pe2M=
 github.com/prometheus/client_golang v1.11.0 h1:HNkLOAEQMIDv/K+04rukrLx6ch7msSRwf3/SASFAGtQ=
 github.com/prometheus/client_golang v1.11.0/go.mod h1:Z6t4BnS23TR94PD6BsDNk8yVqroYurpAkEiz0P2BEV0=
@@ -382,12 +388,14 @@ github.com/prometheus/client_model v0.2.0/go.mod h1:xMI15A0UPsDsEKsMN9yxemIoYk6T
 github.com/prometheus/common v0.0.0-20181113130724-41aa239b4cce/go.mod h1:daVV7qP5qjZbuso7PdcryaAu0sAZbrN9i7WWcTMWvro=
 github.com/prometheus/common v0.4.0/go.mod h1:TNfzLD0ON7rHzMJeJkieUDPYmFC7Snx/y86RQel1bk4=
 github.com/prometheus/common v0.4.1/go.mod h1:TNfzLD0ON7rHzMJeJkieUDPYmFC7Snx/y86RQel1bk4=
+github.com/prometheus/common v0.9.1/go.mod h1:yhUN8i9wzaXS3w1O07YhxHEBxD+W35wd8bs7vj7HSQ4=
 github.com/prometheus/common v0.10.0/go.mod h1:Tlit/dnDKsSWFlCLTWaA1cyBgKHSMdTB80sz/V91rCo=
 github.com/prometheus/common v0.26.0 h1:iMAkS2TDoNWnKM+Kopnx/8tnEStIfpYA0ur0xQzzhMQ=
 github.com/prometheus/common v0.26.0/go.mod h1:M7rCNAaPfAosfx8veZJCuw84e35h3Cfd9VFqTh1DIvc=
 github.com/prometheus/procfs v0.0.0-20181005140218-185b4288413d/go.mod h1:c3At6R/oaqEKCNdg8wHV1ftS6bRYblBhIjjI8uT2IGk=
 github.com/prometheus/procfs v0.0.0-20190507164030-5867b95ac084/go.mod h1:TjEm7ze935MbeOT/UhFTIMYKhuLP4wbCsTZCD3I8kEA=
 github.com/prometheus/procfs v0.0.2/go.mod h1:TjEm7ze935MbeOT/UhFTIMYKhuLP4wbCsTZCD3I8kEA=
+github.com/prometheus/procfs v0.0.8/go.mod h1:7Qr8sr6344vo1JqZ6HhLceV9o3AJ1Ff+GxbHq6oeK9A=
 github.com/prometheus/procfs v0.1.3/go.mod h1:lV6e/gmhEcM9IjHGsFOCxxuZ+z1YqCvr4OA4YeYWdaU=
 github.com/prometheus/procfs v0.2.0/go.mod h1:lV6e/gmhEcM9IjHGsFOCxxuZ+z1YqCvr4OA4YeYWdaU=
 github.com/prometheus/procfs v0.6.0 h1:mxy4L2jP6qMonqmq+aTtOx1ifVWUgG/TAmntgbh3xv4=

vendor/github.com/metalmatze/signal/LICENSE

@@ -0,0 +1,201 @@
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
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+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
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+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
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+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
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+      Work and such Derivative Works in Source or Object form.
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+   3. Grant of Patent License. Subject to the terms and conditions of
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+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
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+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright 2020 Signal Authors
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.

vendor/github.com/metalmatze/signal/healthcheck/checks.go

@@ -0,0 +1,129 @@
+// Copyright 2020 by the contributors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package healthcheck
+
+import (
+	"context"
+	"database/sql"
+	"fmt"
+	"net"
+	"net/http"
+	"runtime"
+	"time"
+)
+
+// TCPDialCheck returns a Check that checks TCP connectivity to the provided
+// endpoint.
+func TCPDialCheck(addr string, timeout time.Duration) Check {
+	return func() error {
+		conn, err := net.DialTimeout("tcp", addr, timeout)
+		if err != nil {
+			return err
+		}
+		return conn.Close()
+	}
+}
+
+// HTTPGetCheck returns a Check that performs an HTTP GET request against the
+// specified URL. The check fails if the response times out or returns a non-200
+// status code.
+func HTTPGetCheck(url string, timeout time.Duration) Check {
+	return func() error {
+		return HTTPCheck(url, http.MethodGet, http.StatusOK, timeout)()
+	}
+}
+
+// HTTPCheck returns a Check that performs a HTTP request against the specified URL.
+// The Check fails if the response times out or returns an unexpected status code.
+func HTTPCheck(url string, method string, status int, timeout time.Duration) Check {
+	client := &http.Client{
+		Timeout: timeout,
+		CheckRedirect: func(*http.Request, []*http.Request) error {
+			return http.ErrUseLastResponse
+		},
+	}
+
+	return HTTPCheckClient(client, url, method, status, timeout)
+}
+
+// HTTPCheckClient returns a Check that performs a HTTP request against the specified URL.
+// The Check fails if the response times out or returns an unexpected status code.
+// On top of that it uses a custom client specified by the caller.
+func HTTPCheckClient(client *http.Client, url string, method string, status int, timeout time.Duration) Check {
+	return func() error {
+		ctx, cancel := context.WithTimeout(context.Background(), timeout)
+		defer cancel()
+
+		req, err := http.NewRequest(method, url, nil)
+		if err != nil {
+			return err
+		}
+		req = req.WithContext(ctx)
+
+		resp, err := client.Do(req)
+		if err != nil {
+			return err
+		}
+		defer resp.Body.Close()
+
+		if resp.StatusCode != status {
+			return fmt.Errorf("returned status %d, expected %d", resp.StatusCode, status)
+		}
+		return nil
+	}
+}
+
+// DatabasePingCheck returns a Check that validates connectivity to a
+// database/sql.DB using Ping().
+func DatabasePingCheck(database *sql.DB, timeout time.Duration) Check {
+	return func() error {
+		ctx, cancel := context.WithTimeout(context.Background(), timeout)
+		defer cancel()
+		if database == nil {
+			return fmt.Errorf("database is nil")
+		}
+		return database.PingContext(ctx)
+	}
+}
+
+// DNSResolveCheck returns a Check that makes sure the provided host can resolve
+// to at least one IP address within the specified timeout.
+func DNSResolveCheck(host string, timeout time.Duration) Check {
+	resolver := net.Resolver{}
+	return func() error {
+		ctx, cancel := context.WithTimeout(context.Background(), timeout)
+		defer cancel()
+		addrs, err := resolver.LookupHost(ctx, host)
+		if err != nil {
+			return err
+		}
+		if len(addrs) < 1 {
+			return fmt.Errorf("could not resolve host")
+		}
+		return nil
+	}
+}
+
+// GoroutineCountCheck returns a Check that fails if too many goroutines are
+// running (which could indicate a resource leak).
+func GoroutineCountCheck(threshold int) Check {
+	return func() error {
+		count := runtime.NumGoroutine()
+		if count > threshold {
+			return fmt.Errorf("too many goroutines (%d > %d)", count, threshold)
+		}
+		return nil
+	}
+}

vendor/github.com/metalmatze/signal/healthcheck/doc.go

@@ -0,0 +1,24 @@
+// Copyright 2020 by the contributors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+/*
+Package healthcheck helps you implement liveness and readiness checks
+for your application. It supports synchronous and asynchronous (background)
+checks. It can optionally report each check's status as a set of Prometheus
+gauge metrics for cluster-wide monitoring and alerting.
+
+It also includes a small library of generic checks for DNS, TCP, and HTTP
+reachability as well as Goroutine usage.
+*/
+package healthcheck

vendor/github.com/metalmatze/signal/healthcheck/handler.go

@@ -0,0 +1,103 @@
+// Copyright 2020 by the contributors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package healthcheck
+
+import (
+	"encoding/json"
+	"net/http"
+	"sync"
+)
+
+// basicHandler is a basic Handler implementation.
+type basicHandler struct {
+	http.ServeMux
+	checksMutex     sync.RWMutex
+	livenessChecks  map[string]Check
+	readinessChecks map[string]Check
+}
+
+// NewHandler creates a new basic Handler
+func NewHandler() Handler {
+	h := &basicHandler{
+		livenessChecks:  make(map[string]Check),
+		readinessChecks: make(map[string]Check),
+	}
+	h.Handle("/live", http.HandlerFunc(h.LiveEndpoint))
+	h.Handle("/ready", http.HandlerFunc(h.ReadyEndpoint))
+	return h
+}
+
+func (s *basicHandler) LiveEndpoint(w http.ResponseWriter, r *http.Request) {
+	s.handle(w, r, s.livenessChecks)
+}
+
+func (s *basicHandler) ReadyEndpoint(w http.ResponseWriter, r *http.Request) {
+	s.handle(w, r, s.readinessChecks, s.livenessChecks)
+}
+
+func (s *basicHandler) AddLivenessCheck(name string, check Check) {
+	s.checksMutex.Lock()
+	defer s.checksMutex.Unlock()
+	s.livenessChecks[name] = check
+}
+
+func (s *basicHandler) AddReadinessCheck(name string, check Check) {
+	s.checksMutex.Lock()
+	defer s.checksMutex.Unlock()
+	s.readinessChecks[name] = check
+}
+
+func (s *basicHandler) collectChecks(checks map[string]Check, resultsOut map[string]string, statusOut *int) {
+	s.checksMutex.RLock()
+	defer s.checksMutex.RUnlock()
+	for name, check := range checks {
+		if err := check(); err != nil {
+			*statusOut = http.StatusServiceUnavailable
+			resultsOut[name] = err.Error()
+		} else {
+			resultsOut[name] = "OK"
+		}
+	}
+}
+
+func (s *basicHandler) handle(w http.ResponseWriter, r *http.Request, checks ...map[string]Check) {
+	if r.Method != http.MethodGet {
+		http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
+		return
+	}
+
+	checkResults := make(map[string]string)
+	status := http.StatusOK
+	for _, checks := range checks {
+		s.collectChecks(checks, checkResults, &status)
+	}
+
+	// write out the response code and content type header
+	w.Header().Set("Content-Type", "application/json; charset=utf-8")
+	w.WriteHeader(status)
+
+	// if ?hide=1, return an empty body. Kubernetes only cares about the
+	// HTTP status code, so we won't waste bytes on the full body.
+	if r.URL.Query().Get("hide") == "1" {
+		_, _ = w.Write([]byte("{}\n"))
+		return
+	}
+
+	// otherwise, write the JSON body ignoring any encoding errors (which
+	// shouldn't really be possible since we're encoding a map[string]string).
+	encoder := json.NewEncoder(w)
+	encoder.SetIndent("", "    ")
+	_ = encoder.Encode(checkResults)
+}

vendor/github.com/metalmatze/signal/healthcheck/metrics_handler.go

@@ -0,0 +1,72 @@
+// Copyright 2020 by the contributors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package healthcheck
+
+import (
+	"net/http"
+
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+type metricsHandler struct {
+	handler  Handler
+	registry prometheus.Registerer
+}
+
+// NewMetricsHandler returns a healthy Handler that writes the current check status
+// into the provided Prometheus registry.
+func NewMetricsHandler(handler Handler, registry prometheus.Registerer) Handler {
+	return &metricsHandler{
+		handler:  handler,
+		registry: registry,
+	}
+}
+
+func (h *metricsHandler) AddLivenessCheck(name string, check Check) {
+	h.handler.AddLivenessCheck(name, h.wrap(prometheus.Labels{"name": name, "check": "live"}, check))
+}
+
+func (h *metricsHandler) AddReadinessCheck(name string, check Check) {
+	h.handler.AddReadinessCheck(name, h.wrap(prometheus.Labels{"name": name, "check": "ready"}, check))
+}
+
+func (h *metricsHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	h.handler.ServeHTTP(w, r)
+}
+
+func (h *metricsHandler) LiveEndpoint(w http.ResponseWriter, r *http.Request) {
+	h.handler.LiveEndpoint(w, r)
+}
+
+func (h *metricsHandler) ReadyEndpoint(w http.ResponseWriter, r *http.Request) {
+	h.handler.ReadyEndpoint(w, r)
+}
+
+func (h *metricsHandler) wrap(labels prometheus.Labels, check Check) Check {
+	h.registry.MustRegister(prometheus.NewGaugeFunc(
+		prometheus.GaugeOpts{
+			Name:        "healthcheck",
+			Help:        "Indicates if check is healthy (1 is healthy, 0 is unhealthy)",
+			ConstLabels: labels,
+		},
+		func() float64 {
+			if check() != nil {
+				return 0
+			}
+			return 1
+		},
+	))
+	return check
+}

vendor/github.com/metalmatze/signal/healthcheck/timeout.go

@@ -0,0 +1,52 @@
+// Copyright 2020 by the contributors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package healthcheck
+
+import (
+	"fmt"
+	"time"
+)
+
+// TimeoutError is the error returned when a Timeout-wrapped Check takes too long
+type timeoutError time.Duration
+
+func (e timeoutError) Error() string {
+	return fmt.Sprintf("timed out after %s", time.Duration(e).String())
+}
+
+// Timeout returns whether this error is a timeout (always true for timeoutError)
+func (e timeoutError) Timeout() bool {
+	return true
+}
+
+// Temporary returns whether this error is temporary (always true for timeoutError)
+func (e timeoutError) Temporary() bool {
+	return true
+}
+
+// Timeout adds a timeout to a Check. If the underlying check takes longer than
+// the timeout, it returns an error.
+func Timeout(check Check, timeout time.Duration) Check {
+	return func() error {
+		c := make(chan error, 1)
+		go func() { c <- check() }()
+		select {
+		case err := <-c:
+			return err
+		case <-time.After(timeout):
+			return timeoutError(timeout)
+		}
+	}
+}

vendor/github.com/metalmatze/signal/healthcheck/types.go

@@ -0,0 +1,52 @@
+// Copyright 2020 by the contributors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package healthcheck
+
+import (
+	"net/http"
+)
+
+// Check is a health/readiness check.
+type Check func() error
+
+// Handler is an http.Handler with additional methods that register health and
+// readiness checks. It handles handle "/live" and "/ready" HTTP
+// endpoints.
+type Handler interface {
+	// The Handler is an http.Handler, so it can be exposed directly and handle
+	// /live and /ready endpoints.
+	http.Handler
+
+	// AddLivenessCheck adds a check that indicates that this instance of the
+	// application should be destroyed or restarted. A failed liveness check
+	// indicates that this instance is unhealthy, not some upstream dependency.
+	// Every liveness check is also included as a readiness check.
+	AddLivenessCheck(name string, check Check)
+
+	// AddReadinessCheck adds a check that indicates that this instance of the
+	// application is currently unable to serve requests because of an upstream
+	// or some transient failure. If a readiness check fails, this instance
+	// should no longer receiver requests, but should not be restarted or
+	// destroyed.
+	AddReadinessCheck(name string, check Check)
+
+	// LiveEndpoint is the HTTP handler for just the /live endpoint, which is
+	// useful if you need to attach it into your own HTTP handler tree.
+	LiveEndpoint(http.ResponseWriter, *http.Request)
+
+	// ReadyEndpoint is the HTTP handler for just the /ready endpoint, which is
+	// useful if you need to attach it into your own HTTP handler tree.
+	ReadyEndpoint(http.ResponseWriter, *http.Request)
+}

vendor/github.com/metalmatze/signal/internalserver/handler.go

@@ -0,0 +1,138 @@
+// Copyright 2021 by the contributors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package internalserver
+
+import (
+	"fmt"
+	"net/http"
+	"net/http/pprof"
+	"sort"
+
+	"github.com/metalmatze/signal/healthcheck"
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
+)
+
+// Handler is a http.ServeMux that knows about all endpoints to render a nice index page.
+type Handler struct {
+	http.ServeMux
+	endpoints []endpoint
+	name      string
+}
+
+// endpoint has a description to a pattern.
+type endpoint struct {
+	Pattern     string
+	Description string
+}
+
+// NewHandler creates a new internalserver Handler.
+func NewHandler(options ...Option) *Handler {
+	h := &Handler{name: "Internal"}
+
+	for _, option := range options {
+		option(h)
+	}
+
+	h.HandleFunc("/", h.index)
+
+	return h
+}
+
+// AddEndpoint wraps HandleFunc for adding http handlers to add a meaningful description to the index page.
+func (h *Handler) AddEndpoint(pattern string, description string, handler http.HandlerFunc) {
+	h.endpoints = append(h.endpoints, endpoint{
+		Pattern:     pattern,
+		Description: description,
+	})
+
+	// Sort endpoints by pattern after adding a new one, to always show them in the same order.
+	sort.Slice(h.endpoints, func(i, j int) bool {
+		return h.endpoints[i].Pattern < h.endpoints[j].Pattern
+	})
+
+	h.HandleFunc(pattern, handler)
+}
+
+func (h *Handler) index(w http.ResponseWriter, r *http.Request) {
+	html := fmt.Sprintf("<html><head><title>%s</title></head><body>\n", h.name)
+	html += fmt.Sprintf("<h1>%s</h1>\n", h.name)
+
+	for _, e := range h.endpoints {
+		html += fmt.Sprintf("<p><a href='%s'>%s - %s</a></p>\n", e.Pattern, e.Pattern, e.Description)
+	}
+	html += `</body></html>`
+
+	w.Header().Set("Content-Type", "text/html; charset=utf-8")
+	_, _ = w.Write([]byte(html))
+}
+
+// Option is a func that modifies the configuration for the internalserver handler.
+type Option func(h *Handler)
+
+// WithName allows to set an application name for the internalserver handler.
+func WithName(name string) Option {
+	return func(h *Handler) {
+		h.name = name
+	}
+}
+
+// WithHealthchecks adds the healthchecks endpoints /live and /ready to the internalserver.
+func WithHealthchecks(healthchecks healthcheck.Handler) Option {
+	return func(h *Handler) {
+		h.AddEndpoint(
+			"/live",
+			"Exposes liveness checks",
+			healthchecks.LiveEndpoint,
+		)
+		h.AddEndpoint(
+			"/ready",
+			"Exposes readiness checks",
+			healthchecks.ReadyEndpoint,
+		)
+	}
+}
+
+// WithPrometheusRegistry adds a /metrics endpoint to the internalserver.
+func WithPrometheusRegistry(registry *prometheus.Registry) Option {
+	return func(h *Handler) {
+		h.AddEndpoint(
+			"/metrics",
+			"Exposes Prometheus metrics",
+			promhttp.HandlerFor(registry, promhttp.HandlerOpts{}).ServeHTTP,
+		)
+	}
+}
+
+// WithPProf adds all pprof endpoints under /debug to the internalserver.
+func WithPProf() Option {
+	return func(h *Handler) {
+		m := http.NewServeMux()
+		m.HandleFunc("/debug/pprof/", pprof.Index)
+		m.HandleFunc("/debug/pprof/cmdline", pprof.Cmdline)
+		m.HandleFunc("/debug/pprof/profile", pprof.Profile)
+		m.HandleFunc("/debug/pprof/symbol", pprof.Symbol)
+		m.HandleFunc("/debug/pprof/trace", pprof.Trace)
+		m.HandleFunc("/debug/", func(w http.ResponseWriter, r *http.Request) {
+			http.Redirect(w, r, "/debug/pprof/", http.StatusMovedPermanently)
+		})
+
+		h.AddEndpoint(
+			"/debug/",
+			"Exposes pprof endpoints to consume via HTTP",
+			m.ServeHTTP,
+		)
+	}
+}

vendor/modules.txt

@@ -127,6 +127,10 @@ github.com/mdlayher/netlink/nlenc
 # github.com/mdlayher/socket v0.0.0-20211102153432-57e3fa563ecb
 ## explicit; go 1.17
 github.com/mdlayher/socket
+# github.com/metalmatze/signal v0.0.0-20210307161603-1c9aa721a97a
+## explicit; go 1.14
+github.com/metalmatze/signal/healthcheck
+github.com/metalmatze/signal/internalserver
 # github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd
 ## explicit
 github.com/modern-go/concurrent