Merge #136: Support building with Go modules

49319f6a7a Cirrus: Mark cyclop,revive linters as non-mandatory (Jeremy Rand)
981e87e4e0 Cirrus: Run with both modules enabled and disabled (Jeremy Rand)
ae92da7a1b README: document building with Go modules (Jeremy Rand)

Pull request description:

Top commit has no ACKs.

Tree-SHA512: 14e086a06782b258f742dc6f3a2293454022ec4cd29225d430e3511fa0598d5251f6d1e1b3e9919bcb41e4308680bb2b886f7dc750323f3c290eb4ab90ac9151

.cirrus.yml

@@ -11,10 +11,30 @@ task:
     - apt-get install -y libcap-dev
   path_script:
     - source testdata/move_to_gopath.bash
-  fetch_script:
-    - go get -tags "$GOX_TAGS" -d -v -t github.com/$CIRRUS_REPO_FULL_NAME/...
-    - go generate github.com/namecoin/x509-compressed/...
-    - go get -tags "$GOX_TAGS" -d -v -t github.com/$CIRRUS_REPO_FULL_NAME/...
+  matrix:
+    - env:
+        GO111MODULE: "off"
+      fetch_script:
+        - go get -tags "$GOX_TAGS" -d -v -t github.com/$CIRRUS_REPO_FULL_NAME/...
+        - GOOS=windows go get -tags "$GOX_TAGS" -d -v -t github.com/$CIRRUS_REPO_FULL_NAME/...
+        - go generate github.com/namecoin/x509-compressed/...
+        - go get -tags "$GOX_TAGS" -d -v -t github.com/$CIRRUS_REPO_FULL_NAME/...
+    - x509_script:
+        - cd $(go env GOPATH)/src/github.com/"$CIRRUS_REPO_FULL_NAME"
+        - cd ../
+        - git clone https://github.com/namecoin/x509-compressed.git
+        - cd x509-compressed
+        - go mod init
+        - go mod tidy
+        - go generate ./...
+        - go mod tidy
+        - go install -v ./...
+      fetch_script:
+        - cd $(go env GOPATH)/src/github.com/"$CIRRUS_REPO_FULL_NAME"
+        - go mod init
+        - go mod tidy
+        - go mod edit -replace github.com/namecoin/x509-compressed=../x509-compressed
+        - go mod tidy
   lint_script:
     - cd $(go env GOPATH)/src/github.com/$CIRRUS_REPO_FULL_NAME/
     - golangci-lint run --no-config --enable-all --disable gochecknoglobals,gomnd $GOLANGCI_ARGS -v --timeout 5m --out-format json > $CIRRUS_WORKING_DIR/lint-report.json
@@ -24,7 +44,7 @@ task:
         GOLANGCI_ARGS: "--new-from-rev=HEAD~"
     - name: Go Lint $GOOS Mandatory
       env:
-        GOLANGCI_ARGS: "--disable=deadcode,errcheck,errorlint,exhaustivestruct,forbidigo,funlen,gci,gocognit,gocritic,godot,godox,goerr113,gofmt,gofumpt,goimports,golint,gosec,gosimple,ineffassign,lll,maligned,nakedret,nestif,nlreturn,nolintlint,paralleltest,scopelint,staticcheck,stylecheck,thelper,unconvert,unparam,unused,whitespace,wrapcheck,wsl"
+        GOLANGCI_ARGS: "--disable=cyclop,deadcode,errcheck,errorlint,exhaustivestruct,forbidigo,funlen,gci,gocognit,gocritic,godot,godox,goerr113,gofmt,gofumpt,goimports,golint,gosec,gosimple,ineffassign,lll,maligned,nakedret,nestif,nlreturn,nolintlint,paralleltest,revive,scopelint,staticcheck,stylecheck,thelper,unconvert,unparam,unused,whitespace,wrapcheck,wsl"
     - name: Go Lint $GOOS
       env:
         GOLANGCI_ARGS: ""
@@ -59,11 +79,38 @@ task:
     - apt-get install -y libcap-dev
   path_script:
     - source testdata/move_to_gopath.bash
-  fetch_script:
-    - go get -tags "$GOX_TAGS" -d -v -t github.com/$CIRRUS_REPO_FULL_NAME/...
-    - go generate github.com/namecoin/x509-compressed/...
-    - go get -tags "$GOX_TAGS" -d -v -t github.com/$CIRRUS_REPO_FULL_NAME/...
-  test_script: go test -tags "$GOX_TAGS" -v github.com/$CIRRUS_REPO_FULL_NAME/...
+  matrix:
+    - env:
+        GO111MODULE: "off"
+      fetch_script:
+        - go get -tags "$GOX_TAGS" -d -v -t github.com/$CIRRUS_REPO_FULL_NAME/...
+        - GOOS=windows go get -tags "$GOX_TAGS" -d -v -t github.com/$CIRRUS_REPO_FULL_NAME/...
+        - go generate github.com/namecoin/x509-compressed/...
+        - go get -tags "$GOX_TAGS" -d -v -t github.com/$CIRRUS_REPO_FULL_NAME/...
+    - x509_script:
+        - cd $(go env GOPATH)/src/github.com/"$CIRRUS_REPO_FULL_NAME"
+        - cd ../
+        - git clone https://github.com/namecoin/x509-compressed.git
+        - cd x509-compressed
+        - go mod init
+        - go mod tidy
+        - go generate ./...
+        - go mod tidy
+        - go install -v ./...
+      fetch_script:
+        - cd $(go env GOPATH)/src/github.com/"$CIRRUS_REPO_FULL_NAME"
+        - go mod init
+        - go mod tidy
+        - go mod edit -replace github.com/namecoin/x509-compressed=../x509-compressed
+        - go mod tidy
+        # Get the test suite
+        - mkdir -p $(go env GOPATH)/src/github.com/hlandau
+        - cd $(go env GOPATH)/src/github.com/hlandau
+        - git clone https://github.com/hlandau/nctestsuite.git
+  test_script:
+    - cd $(go env GOPATH)/src/github.com/"$CIRRUS_REPO_FULL_NAME"
+    - go install -tags "$GOX_TAGS" -v ./...
+    - go test -tags "$GOX_TAGS" -v github.com/$CIRRUS_REPO_FULL_NAME/...
   env:
     GOX_TAGS: ""
     GO_VERSION: latest
@@ -86,17 +133,37 @@ task:
     - go get github.com/mitchellh/gox
   path_script:
     - source testdata/move_to_gopath.bash
-  fetch_script:
-    - go get -tags "$GOX_TAGS" -d -v -t github.com/$CIRRUS_REPO_FULL_NAME/...
-    - GOOS=windows GOARCH=amd64 go get -tags "$GOX_TAGS" -d -v -t github.com/$CIRRUS_REPO_FULL_NAME/...
-    - go generate github.com/namecoin/x509-compressed/...
-    - go get -tags "$GOX_TAGS" -d -v -t github.com/$CIRRUS_REPO_FULL_NAME/...
+  matrix:
+    - env:
+        GO111MODULE: "off"
+      fetch_script:
+        - go get -tags "$GOX_TAGS" -d -v -t github.com/$CIRRUS_REPO_FULL_NAME/...
+        - GOOS=windows go get -tags "$GOX_TAGS" -d -v -t github.com/$CIRRUS_REPO_FULL_NAME/...
+        - go generate github.com/namecoin/x509-compressed/...
+        - go get -tags "$GOX_TAGS" -d -v -t github.com/$CIRRUS_REPO_FULL_NAME/...
+    - x509_script:
+        - cd $(go env GOPATH)/src/github.com/"$CIRRUS_REPO_FULL_NAME"
+        - cd ../
+        - git clone https://github.com/namecoin/x509-compressed.git
+        - cd x509-compressed
+        - go mod init
+        - go mod tidy
+        - go generate ./...
+        - go mod tidy
+        - go install -v ./...
+      fetch_script:
+        - cd $(go env GOPATH)/src/github.com/"$CIRRUS_REPO_FULL_NAME"
+        - go mod init
+        - go mod tidy
+        - go mod edit -replace github.com/namecoin/x509-compressed=../x509-compressed
+        - go mod tidy
   build_script:
     - rm -rf idist
-    - CGO_ENABLED=1 gox -tags="$GOX_TAGS" -parallel=8 -osarch 'linux/386 linux/amd64 linux/arm linux/arm64 linux/ppc64le' -output "$GOPATH/releasing/idist/$CIRRUS_REPO_NAME-$CIRRUS_TAG-{{.OS}}_{{.Arch}}/bin/{{.Dir}}" github.com/$CIRRUS_REPO_FULL_NAME/...
-    - CGO_ENABLED=0 gox -tags="$GOX_TAGS" -parallel=8 -osarch 'darwin/amd64 freebsd/386 freebsd/amd64 freebsd/arm linux/ppc64 openbsd/386 openbsd/amd64 netbsd/386 netbsd/amd64 netbsd/arm dragonfly/amd64 solaris/amd64 windows/386 windows/amd64' -output "$GOPATH/releasing/idist/$CIRRUS_REPO_NAME-$CIRRUS_TAG-{{.OS}}_{{.Arch}}/bin/{{.Dir}}" github.com/$CIRRUS_REPO_FULL_NAME/...
-    - mv $GOPATH/releasing/idist ./idist
+    - cd $(go env GOPATH)/src/github.com/"$CIRRUS_REPO_FULL_NAME"
+    - CGO_ENABLED=1 gox -tags="$GOX_TAGS" -parallel=8 -osarch 'linux/386 linux/amd64 linux/arm linux/arm64 linux/ppc64le' -output "$GOPATH/releasing/idist/$CIRRUS_REPO_NAME-$CIRRUS_TAG-{{.OS}}_{{.Arch}}/bin/{{.Dir}}" ./...
+    - CGO_ENABLED=0 gox -tags="$GOX_TAGS" -parallel=8 -osarch 'darwin/amd64 freebsd/386 freebsd/amd64 freebsd/arm linux/ppc64 openbsd/386 openbsd/amd64 netbsd/386 netbsd/amd64 netbsd/arm dragonfly/amd64 solaris/amd64 windows/386 windows/amd64' -output "$GOPATH/releasing/idist/$CIRRUS_REPO_NAME-$CIRRUS_TAG-{{.OS}}_{{.Arch}}/bin/{{.Dir}}" ./...
   dist_script:
+    - mv $GOPATH/releasing/idist ./idist
     - bash "testdata/dist.bash"
   binaries_artifacts:
     path: "dist/*"

README.md

@@ -90,21 +90,37 @@ Prerequisites:
    installed. (Most distributions will have a package called `libcap-dev` or
    similar.)
 
-Option A: Using Go build commands (works on any platform):
+Option A: Using Go build commands without Go modules (works on any platform with Bash; only Go 1.15-1.16.x; will not work on Go 1.17+):
 
-1. Ensure you have the GOPATH environment variable set. (For those not
+1. Ensure you have the `GOPATH` environment variable set. (For those not
    familar with Go, setting it to the path to an empty directory will suffice.
    The directory will be filled with build files.)
 
-2. Run `go get -d -t -u github.com/namecoin/ncdns/...`. The ncdns source code will be
+2. Run `export GO111MODULE=off` to disable Go modules.
+
+3. Run `go get -d -t -u github.com/namecoin/ncdns/...`. The ncdns source code will be
    retrieved automatically.
 
-3. Run `go generate github.com/namecoin/x509_compressed/...`.  The compressed public key patch will be applied.
+4. Run `go generate github.com/namecoin/x509-compressed/...`.  The compressed public key patch will be applied.
+
+5. Run `go get -t -u github.com/namecoin/ncdns/...`.  ncdns will be built. The binaries will be at `$GOPATH/bin/ncdns`.
+
+Option B: Using Go build commands with Go modules (works on any platform with Bash; Go 1.15+:
+
+1. Install [x509-compressed](https://github.com/namecoin/x509-compressed) according to its "with Go modules" instructions.  Clone ncdns to a sibling directory of x509-compressed.
+
+2. Run the following in the ncdns directory to set up Go modules:
+   
+   ~~~
+   go mod init
+   go mod tidy
+   go mod edit -replace github.com/namecoin/x509-compressed=../x509-compressed
+   go mod tidy
+   ~~~
 
-4. Run `go get -t -u github.com/namecoin/ncdns/...`.  ncdns will be built. The binaries will be at
-   $GOPATH/bin/ncdns.
+3. Run `go install ./...`.  ncdns will be built. The binaries will be at `$GOPATH/bin/ncdns`.
 
-Option B: Using Makefile (non-Windows platforms):
+Option C: Using Makefile (non-Windows platforms):
 
 1. Run `make`. The source repository will be retrieved via `go get`
    automatically.