Add roughtime static code analysis and fix all violations (#5370)

* Add roughtime static code analysis and fix all violations
* Merge branch 'master' into enforce-roughtime

tools/analyzers/roughtime/BUILD.bazel

@@ -0,0 +1,25 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_library", "go_tool_library")
+
+go_library(
+    name = "go_default_library",
+    srcs = ["analyzer.go"],
+    importpath = "github.com/prysmaticlabs/prysm/tools/analyzers/roughtime",
+    visibility = ["//visibility:public"],
+    deps = [
+        "@org_golang_x_tools//go/analysis:go_default_library",
+        "@org_golang_x_tools//go/analysis/passes/inspect:go_default_library",
+        "@org_golang_x_tools//go/ast/inspector:go_default_library",
+    ],
+)
+
+go_tool_library(
+    name = "go_tool_library",
+    srcs = ["analyzer.go"],
+    importpath = "github.com/prysmaticlabs/prysm/tools/analyzers/roughtime",
+    visibility = ["//visibility:public"],
+    deps = [
+        "@org_golang_x_tools//go/analysis:go_tool_library",
+        "@org_golang_x_tools//go/analysis/passes/inspect:go_tool_library",
+        "@org_golang_x_tools//go/ast/inspector:go_tool_library",
+    ],
+)

tools/analyzers/roughtime/analyzer.go

@@ -0,0 +1,52 @@
+package roughtime
+
+import (
+	"go/ast"
+
+	"golang.org/x/tools/go/analysis"
+	"golang.org/x/tools/go/analysis/passes/inspect"
+	"golang.org/x/tools/go/ast/inspector"
+)
+
+// Doc explaining the tool.
+const Doc = "Tool to enforce the use of roughtime.Now() rather than time.Now(). This is " +
+	"critically important to certain ETH2 systems where the client / server must be in sync with " +
+	"some NTP network."
+
+// Analyzer runs static analysis.
+var Analyzer = &analysis.Analyzer{
+	Name:     "roughtime",
+	Doc:      Doc,
+	Requires: []*analysis.Analyzer{inspect.Analyzer},
+	Run:      run,
+}
+
+func run(pass *analysis.Pass) (interface{}, error) {
+	inspect := pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
+
+	nodeFilter := []ast.Node{
+		(*ast.CallExpr)(nil),
+	}
+
+	inspect.Preorder(nodeFilter, func(node ast.Node) {
+		if ce, ok := node.(*ast.CallExpr); ok {
+			if isPkgDot(ce.Fun, "time", "Now") {
+				pass.Reportf(node.Pos(), "Do not use time.Now(), use "+
+					"github.com/prysmaticlabs/prysm/shared/roughtime.Now() or add an exclusion "+
+					"to //:nogo.json.")
+			}
+		}
+	})
+
+	return nil, nil
+}
+
+func isPkgDot(expr ast.Expr, pkg, name string) bool {
+	sel, ok := expr.(*ast.SelectorExpr)
+	return ok && isIdent(sel.X, pkg) && isIdent(sel.Sel, name)
+}
+
+func isIdent(expr ast.Expr, ident string) bool {
+	id, ok := expr.(*ast.Ident)
+	return ok && id.Name == ident
+}