diff --git a/.golangci.yml b/.golangci.yml new file mode 100644 index 0000000..8fb2844 --- /dev/null +++ b/.golangci.yml @@ -0,0 +1,176 @@ +# Derived from https://github.com/golangci/golangci-lint/blob/master/.golangci.example.yml + +--- + +run: + # timeout for analysis, e.g. 30s, 5m, default is 1m + timeout: 5m + # Force readonly modules usage for checking + modules-download-mode: readonly + +output: + formats: + - format: tab + path: stdout + +issues: + # This disables the included exclude-list in golangci-lint as that + # list for example fully hides G304 gosec rule, errcheck, exported + # rule of revive and other errors one really wants to see. + # Smme detail: https://github.com/golangci/golangci-lint/issues/456 + exclude-use-default: false + # Don't limit the number of shown issues: Report ALL of them + max-issues-per-linter: 0 + max-same-issues: 0 + +linters: + disable-all: true + enable: + - asciicheck # Simple linter to check that your code does not contain non-ASCII identifiers [fast: true, auto-fix: false] + - bidichk # Checks for dangerous unicode character sequences [fast: true, auto-fix: false] + - bodyclose # checks whether HTTP response body is closed successfully [fast: true, auto-fix: false] + - containedctx # containedctx is a linter that detects struct contained context.Context field [fast: true, auto-fix: false] + - contextcheck # check the function whether use a non-inherited context [fast: false, auto-fix: false] + - dogsled # Checks assignments with too many blank identifiers (e.g. x, _, _, _, := f()) [fast: true, auto-fix: false] + - durationcheck # check for two durations multiplied together [fast: false, auto-fix: false] + - errcheck # Errcheck is a program for checking for unchecked errors in go programs. These unchecked errors can be critical bugs in some cases [fast: false, auto-fix: false] + - errchkjson # Checks types passed to the json encoding functions. Reports unsupported types and optionally reports occations, where the check for the returned error can be omitted. [fast: false, auto-fix: false] + - exportloopref # checks for pointers to enclosing loop variables [fast: true, auto-fix: false] + - forbidigo # Forbids identifiers [fast: true, auto-fix: false] + - funlen # Tool for detection of long functions [fast: true, auto-fix: false] + - gocognit # Computes and checks the cognitive complexity of functions [fast: true, auto-fix: false] + - goconst # Finds repeated strings that could be replaced by a constant [fast: true, auto-fix: false] + - gocritic # The most opinionated Go source code linter [fast: true, auto-fix: false] + - gocyclo # Computes and checks the cyclomatic complexity of functions [fast: true, auto-fix: false] + - godox # Tool for detection of FIXME, TODO and other comment keywords [fast: true, auto-fix: false] + - gofmt # Gofmt checks whether code was gofmt-ed. By default this tool runs with -s option to check for code simplification [fast: true, auto-fix: true] + - gofumpt # Gofumpt checks whether code was gofumpt-ed. [fast: true, auto-fix: true] + - goimports # Goimports does everything that gofmt does. Additionally it checks unused imports [fast: true, auto-fix: true] + - gomnd # An analyzer to detect magic numbers. [fast: true, auto-fix: false] + - gosec # Inspects source code for security problems [fast: true, auto-fix: false] + - gosimple # Linter for Go source code that specializes in simplifying a code [fast: true, auto-fix: false] + - govet # Vet examines Go source code and reports suspicious constructs, such as Printf calls whose arguments do not align with the format string [fast: true, auto-fix: false] + - ineffassign # Detects when assignments to existing variables are not used [fast: true, auto-fix: false] + - misspell # Finds commonly misspelled English words in comments [fast: true, auto-fix: true] + - nakedret # Finds naked returns in functions greater than a specified function length [fast: true, auto-fix: false] + - nilerr # Finds the code that returns nil even if it checks that the error is not nil. [fast: false, auto-fix: false] + - nilnil # Checks that there is no simultaneous return of `nil` error and an invalid value. [fast: false, auto-fix: false] + - noctx # noctx finds sending http request without context.Context [fast: true, auto-fix: false] + - nolintlint # Reports ill-formed or insufficient nolint directives [fast: true, auto-fix: false] + - revive # Fast, configurable, extensible, flexible, and beautiful linter for Go. Drop-in replacement of golint. [fast: false, auto-fix: false] + - staticcheck # Staticcheck is a go vet on steroids, applying a ton of static analysis checks [fast: true, auto-fix: false] + - stylecheck # Stylecheck is a replacement for golint [fast: true, auto-fix: false] + - tenv # tenv is analyzer that detects using os.Setenv instead of t.Setenv since Go1.17 [fast: false, auto-fix: false] + - typecheck # Like the front-end of a Go compiler, parses and type-checks Go code [fast: true, auto-fix: false] + - unconvert # Remove unnecessary type conversions [fast: true, auto-fix: false] + - unused # Checks Go code for unused constants, variables, functions and types [fast: false, auto-fix: false] + - wastedassign # wastedassign finds wasted assignment statements. [fast: false, auto-fix: false] + - wrapcheck # Checks that errors returned from external packages are wrapped [fast: false, auto-fix: false] + +linters-settings: + funlen: + lines: 100 + statements: 60 + + gocyclo: + # minimal code complexity to report, 30 by default (but we recommend 10-20) + min-complexity: 15 + + gomnd: + settings: + mnd: + ignored-functions: 'strconv.(?:Format|Parse)\B+' + + revive: + rules: + #- name: add-constant # Suggests using constant for magic numbers and string literals + # Opinion: Makes sense for strings, not for numbers but checks numbers + #- name: argument-limit # Specifies the maximum number of arguments a function can receive | Opinion: Don't need this + - name: atomic # Check for common mistaken usages of the `sync/atomic` package + - name: banned-characters # Checks banned characters in identifiers + arguments: + - 'Íž' # Greek question mark + - name: bare-return # Warns on bare returns + - name: blank-imports # Disallows blank imports + - name: bool-literal-in-expr # Suggests removing Boolean literals from logic expressions + - name: call-to-gc # Warns on explicit call to the garbage collector + #- name: cognitive-complexity # Sets restriction for maximum Cognitive complexity. + # There is a dedicated linter for this + - name: confusing-naming # Warns on methods with names that differ only by capitalization + - name: confusing-results # Suggests to name potentially confusing function results + - name: constant-logical-expr # Warns on constant logical expressions + - name: context-as-argument # `context.Context` should be the first argument of a function. + - name: context-keys-type # Disallows the usage of basic types in `context.WithValue`. + #- name: cyclomatic # Sets restriction for maximum Cyclomatic complexity. + # There is a dedicated linter for this + #- name: datarace # Spots potential dataraces + # Is not (yet) available? + - name: deep-exit # Looks for program exits in funcs other than `main()` or `init()` + - name: defer # Warns on some [defer gotchas](https://blog.learngoprogramming.com/5-gotchas-of-defer-in-go-golang-part-iii-36a1ab3d6ef1) + - name: dot-imports # Forbids `.` imports. + - name: duplicated-imports # Looks for packages that are imported two or more times + - name: early-return # Spots if-then-else statements that can be refactored to simplify code reading + - name: empty-block # Warns on empty code blocks + - name: empty-lines # Warns when there are heading or trailing newlines in a block + - name: errorf # Should replace `errors.New(fmt.Sprintf())` with `fmt.Errorf()` + - name: error-naming # Naming of error variables. + - name: error-return # The error return parameter should be last. + - name: error-strings # Conventions around error strings. + - name: exported # Naming and commenting conventions on exported symbols. + arguments: ['sayRepetitiveInsteadOfStutters'] + #- name: file-header # Header which each file should have. + # Useless without config, have no config for it + - name: flag-parameter # Warns on boolean parameters that create a control coupling + #- name: function-length # Warns on functions exceeding the statements or lines max + # There is a dedicated linter for this + #- name: function-result-limit # Specifies the maximum number of results a function can return + # Opinion: Don't need this + - name: get-return # Warns on getters that do not yield any result + - name: identical-branches # Spots if-then-else statements with identical `then` and `else` branches + - name: if-return # Redundant if when returning an error. + #- name: imports-blacklist # Disallows importing the specified packages + # Useless without config, have no config for it + - name: import-shadowing # Spots identifiers that shadow an import + - name: increment-decrement # Use `i++` and `i--` instead of `i += 1` and `i -= 1`. + - name: indent-error-flow # Prevents redundant else statements. + #- name: line-length-limit # Specifies the maximum number of characters in a lined + # There is a dedicated linter for this + #- name: max-public-structs # The maximum number of public structs in a file. + # Opinion: Don't need this + - name: modifies-parameter # Warns on assignments to function parameters + - name: modifies-value-receiver # Warns on assignments to value-passed method receivers + #- name: nested-structs # Warns on structs within structs + # Opinion: Don't need this + - name: optimize-operands-order # Checks inefficient conditional expressions + #- name: package-comments # Package commenting conventions. + # Opinion: Don't need this + - name: range # Prevents redundant variables when iterating over a collection. + - name: range-val-address # Warns if address of range value is used dangerously + - name: range-val-in-closure # Warns if range value is used in a closure dispatched as goroutine + - name: receiver-naming # Conventions around the naming of receivers. + - name: redefines-builtin-id # Warns on redefinitions of builtin identifiers + #- name: string-format # Warns on specific string literals that fail one or more user-configured regular expressions + # Useless without config, have no config for it + - name: string-of-int # Warns on suspicious casts from int to string + - name: struct-tag # Checks common struct tags like `json`,`xml`,`yaml` + - name: superfluous-else # Prevents redundant else statements (extends indent-error-flow) + - name: time-equal # Suggests to use `time.Time.Equal` instead of `==` and `!=` for equality check time. + - name: time-naming # Conventions around the naming of time variables. + - name: unconditional-recursion # Warns on function calls that will lead to (direct) infinite recursion + - name: unexported-naming # Warns on wrongly named un-exported symbols + - name: unexported-return # Warns when a public return is from unexported type. + - name: unhandled-error # Warns on unhandled errors returned by funcion calls + arguments: + - "fmt.(Fp|P)rint(f|ln|)" + - name: unnecessary-stmt # Suggests removing or simplifying unnecessary statements + - name: unreachable-code # Warns on unreachable code + - name: unused-parameter # Suggests to rename or remove unused function parameters + - name: unused-receiver # Suggests to rename or remove unused method receivers + #- name: use-any # Proposes to replace `interface{}` with its alias `any` + # Is not (yet) available? + - name: useless-break # Warns on useless `break` statements in case clauses + - name: var-declaration # Reduces redundancies around variable declaration. + - name: var-naming # Naming rules. + - name: waitgroup-by-value # Warns on functions taking sync.WaitGroup as a by-value parameter + +... diff --git a/checks.go b/checks.go new file mode 100644 index 0000000..2e8b8c9 --- /dev/null +++ b/checks.go @@ -0,0 +1,151 @@ +package main + +import ( + "errors" + "fmt" + "io" + "net/http" + "net/url" + "os" + "os/exec" + "time" + + "github.com/sirupsen/logrus" + "golang.org/x/net/context" + "gopkg.in/yaml.v3" +) + +const ( + checkKillWait = 100 * time.Millisecond + remoteConfigFetchTimeout = 2 * time.Second +) + +type ( + checkCommand struct { + Name string `yaml:"name"` + Command string `yaml:"command"` + WarnOnly bool `yaml:"warn_only"` + } + + checkResult struct { + Check checkCommand + IsSuccess bool + Streak int64 + } +) + +func executeAndRegisterCheck(ctx context.Context, checkID string) { + var ( + check = checks[checkID] + logger = logrus.WithField("check_id", checkID) + ) + + cmd := exec.Command("/bin/bash", "-e", "-o", "pipefail", "-c", check.Command) //#nosec G204 // Intended to run an user-defined command + cmd.Stderr = logger.WithField("stream", "STDERR").Writer() + if cfg.Verbose { + cmd.Stdout = logger.WithField("stream", "STDOUT").Writer() + } + err := cmd.Start() + + if err == nil { + cmdDone := make(chan error) + go func(cmdDone chan error, cmd *exec.Cmd) { cmdDone <- cmd.Wait() }(cmdDone, cmd) + loop := true + for loop { + select { + case err = <-cmdDone: + loop = false + case <-ctx.Done(): + logger.Error("execution of check will be killed through context timeout") + if err := cmd.Process.Kill(); err != nil { + logger.WithError(err).Error("killing check command") + } + time.Sleep(checkKillWait) + } + } + } + + success := err == nil + + checkResultsLock.Lock() + + if _, ok := checkResults[checkID]; !ok { + checkResults[checkID] = &checkResult{ + Check: check, + } + } + + if success == checkResults[checkID].IsSuccess { + checkResults[checkID].Streak++ + } else { + checkResults[checkID].IsSuccess = success + checkResults[checkID].Streak = 1 + } + + if !success { + logger.WithError(err).WithField("streak", checkResults[checkID].Streak).Warn("check failed, streak increased") + } + + lastResultRegistered = time.Now() + + checkResultsLock.Unlock() +} + +func loadChecks() error { + var rawChecks io.Reader + + if _, err := os.Stat(cfg.CheckDefinitionsFile); err == nil { + // We got a local file, read it + f, err := os.Open(cfg.CheckDefinitionsFile) + if err != nil { + return fmt.Errorf("opening file: %w", err) + } + defer func() { + if err := f.Close(); err != nil { + logrus.WithError(err).Error("closing configfile (leaked fd)") + } + }() + rawChecks = f + } else { + // Check whether we got an URL + if _, err := url.Parse(cfg.CheckDefinitionsFile); err != nil { + return errors.New("definitions file is neither a local file nor a URL") + } + + // We got an URL, fetch and read it + ctx, cancel := context.WithTimeout(context.TODO(), remoteConfigFetchTimeout) + defer cancel() + + req, err := http.NewRequestWithContext(ctx, http.MethodGet, cfg.CheckDefinitionsFile, nil) + if err != nil { + return fmt.Errorf("creating request: %w", err) + } + + resp, err := http.DefaultClient.Do(req) + if err != nil { + return fmt.Errorf("executing request: %w", err) + } + defer func() { + if err := resp.Body.Close(); err != nil { + logrus.WithError(err).Error("closing configfile request body (leaked fd)") + } + }() + rawChecks = resp.Body + } + + tmpResult := map[string]checkCommand{} + if err := yaml.NewDecoder(rawChecks).Decode(&tmpResult); err != nil { + return fmt.Errorf("decoding checks file: %w", err) + } + + checks = tmpResult + return nil +} + +func spawnChecks() { + ctx, _ := context.WithTimeout(context.Background(), cfg.CheckInterval-time.Second) + + for id := range checks { + go executeAndRegisterCheck(ctx, id) + } +} diff --git a/go.mod b/go.mod index 4a0c7aa..9fe64e7 100644 --- a/go.mod +++ b/go.mod @@ -4,14 +4,14 @@ go 1.22.1 require ( github.com/Luzifer/rconfig/v2 v2.5.0 - github.com/gorilla/mux v1.8.1 github.com/robfig/cron/v3 v3.0.1 + github.com/sirupsen/logrus v1.9.3 golang.org/x/net v0.22.0 - gopkg.in/yaml.v2 v2.4.0 + gopkg.in/yaml.v3 v3.0.1 ) require ( github.com/spf13/pflag v1.0.5 // indirect + golang.org/x/sys v0.18.0 // indirect gopkg.in/validator.v2 v2.0.1 // indirect - gopkg.in/yaml.v3 v3.0.1 // indirect ) diff --git a/go.sum b/go.sum index 94df6d2..6246611 100644 --- a/go.sum +++ b/go.sum @@ -1,9 +1,8 @@ github.com/Luzifer/rconfig/v2 v2.5.0 h1:zx5lfQbNX3za4VegID97IeY+M+BmfgHxWJTYA94sxok= github.com/Luzifer/rconfig/v2 v2.5.0/go.mod h1:eGWUPQeCPv/Pr/p0hjmwFgI20uqvwi/Szen69hUzGzU= +github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38= github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c= github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38= -github.com/gorilla/mux v1.8.1 h1:TuBL49tXwgrFYWhqrNgrUNEY92u81SPhu7sTdzQEiWY= -github.com/gorilla/mux v1.8.1/go.mod h1:AKf9I4AEqPTmMytcMc0KkNouC66V3BtZ4qD5fmWSiMQ= github.com/kr/pretty v0.2.1 h1:Fmg33tUaq4/8ym9TJN1x7sLJnHVwhP33CNkpYV/7rwI= github.com/kr/pretty v0.2.1/go.mod h1:ipq/a2n7PKx3OHsz4KJII5eveXtPO4qwEXGdVfWzfnI= github.com/kr/text v0.1.0 h1:45sCR5RtlFHMR4UwH9sdQ5TC8v0qDQCHnXt+kaKSTVE= @@ -12,18 +11,24 @@ github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZb github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4= github.com/robfig/cron/v3 v3.0.1 h1:WdRxkvbJztn8LMz/QEvLN5sBU+xKpSqwwUO1Pjr4qDs= github.com/robfig/cron/v3 v3.0.1/go.mod h1:eQICP3HwyT7UooqI/z+Ov+PtYAWygg1TEWWzGIFLtro= +github.com/sirupsen/logrus v1.9.3 h1:dueUQJ1C2q9oE3F7wvmSGAaVtTmUizReu6fjN8uqzbQ= +github.com/sirupsen/logrus v1.9.3/go.mod h1:naHLuLoDiP4jHNo9R0sCBMtWGeIprob74mVsIT4qYEQ= github.com/spf13/pflag v1.0.5 h1:iy+VFUOCP1a+8yFto/drg2CJ5u0yRoB7fZw3DKv/JXA= github.com/spf13/pflag v1.0.5/go.mod h1:McXfInJRrz4CZXVZOBLb0bTZqETkiAhM9Iw0y3An2Bg= +github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME= +github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg= github.com/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcUk= github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo= golang.org/x/net v0.22.0 h1:9sGLhx7iRIHEiX0oAJ3MRZMUCElJgy7Br1nO+AMN3Tc= golang.org/x/net v0.22.0/go.mod h1:JKghWKKOSdJwpW2GEx0Ja7fmaKnMsbu+MWVZTokSYmg= +golang.org/x/sys v0.0.0-20220715151400-c0bba94af5f8/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg= +golang.org/x/sys v0.18.0 h1:DBdB3niSjOA/O0blCZBqDefyWNYveAYMNF1Wum0DYQ4= +golang.org/x/sys v0.18.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA= gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0= gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c h1:Hei/4ADfdWqJk1ZMxUNpqntNwaWcugrBjAiHlqqRiVk= gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c/go.mod h1:JHkPIbrfpd72SG/EVd6muEfDQjcINNoR0C8j2r3qZ4Q= gopkg.in/validator.v2 v2.0.1 h1:xF0KWyGWXm/LM2G1TrEjqOu4pa6coO9AlWSf3msVfDY= gopkg.in/validator.v2 v2.0.1/go.mod h1:lIUZBlB3Im4s/eYp39Ry/wkR02yOPhZ9IwIRBjuPuG8= -gopkg.in/yaml.v2 v2.4.0 h1:D8xgwECY7CYvx+Y2n4sBz93Jn9JRvxdiyyo8CTfuKaY= -gopkg.in/yaml.v2 v2.4.0/go.mod h1:RDklbk79AGWmwhnvt/jBztapEOGDOx6ZbXqjP6csGnQ= +gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM= gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA= gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM= diff --git a/main.go b/main.go index 736f209..2f317a3 100644 --- a/main.go +++ b/main.go @@ -2,22 +2,16 @@ package main import ( "bytes" - "errors" "fmt" "io" - "log" "net/http" - "net/url" "os" - "os/exec" "strconv" "sync" "time" - "github.com/gorilla/mux" "github.com/robfig/cron/v3" - "golang.org/x/net/context" - "gopkg.in/yaml.v2" + "github.com/sirupsen/logrus" "github.com/Luzifer/rconfig/v2" ) @@ -30,7 +24,8 @@ var ( CheckInterval time.Duration `flag:"check-interval" default:"1m" description:"How often to execute checks (do not set below 10s!)"` ConfigRefreshInterval time.Duration `flag:"config-refresh" default:"10m" description:"How often to update checks from definitions file / url"` - Verbose bool `flag:"verbose,v" default:"false" description:"Attach stdout of the executed commands"` + Verbose bool `flag:"verbose,v" default:"false" description:"Attach stdout of the executed commands"` + LogLevel string `flag:"log-level" default:"info" description:"Log level (debug, info, warn, error, fatal)"` Listen string `flag:"listen" default:":3000" description:"IP/Port to listen on for ELB health checks"` VersionAndExit bool `flag:"version" default:"false" description:"Print version and exit"` @@ -44,157 +39,73 @@ var ( lastResultRegistered time.Time ) -type checkCommand struct { - Name string `yaml:"name"` - Command string `yaml:"command"` - WarnOnly bool `yaml:"warn_only"` - WarnOnlyOld *bool `yaml:"warn-only"` -} - -type checkResult struct { - Check checkCommand - IsSuccess bool - Streak int64 -} - -func init() { - rconfig.Parse(&cfg) - - if cfg.VersionAndExit { - fmt.Printf("elb-instance-status %s\n", version) - os.Exit(0) - } -} - -func loadChecks() error { - var rawChecks io.Reader - - if _, err := os.Stat(cfg.CheckDefinitionsFile); err == nil { - // We got a local file, read it - f, err := os.Open(cfg.CheckDefinitionsFile) - if err != nil { - return err - } - defer f.Close() - rawChecks = f - } else { - // Check whether we got an URL - if _, err := url.Parse(cfg.CheckDefinitionsFile); err != nil { - return errors.New("Definitions file is neither a local file nor a URL") - } - - // We got an URL, fetch and read it - resp, err := http.Get(cfg.CheckDefinitionsFile) - if err != nil { - return err - } - defer resp.Body.Close() - rawChecks = resp.Body +func initApp() (err error) { + rconfig.AutoEnv(true) + if err = rconfig.Parse(&cfg); err != nil { + return fmt.Errorf("parsing CLI options: %w", err) } - tmpResult := map[string]checkCommand{} - if err := yaml.NewDecoder(rawChecks).Decode(&tmpResult); err != nil { - return err + l, err := logrus.ParseLevel(cfg.LogLevel) + if err != nil { + return fmt.Errorf("parsing log-level: %w", err) } + logrus.SetLevel(l) - for name, check := range tmpResult { - if check.WarnOnlyOld != nil { - log.Printf("Parameter 'warn-only' in check %q is deprecated: It's now named 'warn_only'", name) - check.WarnOnly = *check.WarnOnlyOld - } - } - - checks = tmpResult return nil } func main() { - if err := loadChecks(); err != nil { - log.Fatalf("Unable to read definitions file: %s", err) + var err error + if err = initApp(); err != nil { + logrus.WithError(err).Fatal("initializing app") + } + + if cfg.VersionAndExit { + fmt.Printf("elb-instance-status %s\n", version) //nolint:forbidigo + os.Exit(0) + } + + if err = loadChecks(); err != nil { + logrus.WithError(err).Fatal("reading definitions file") } c := cron.New() - c.AddFunc("@every "+cfg.CheckInterval.String(), spawnChecks) - c.AddFunc("@every "+cfg.ConfigRefreshInterval.String(), func() { + + if _, err = c.AddFunc(fmt.Sprintf("@every %s", cfg.CheckInterval), spawnChecks); err != nil { + logrus.WithError(err).Fatal("registering spawn function") + } + + if _, err = c.AddFunc(fmt.Sprintf("@every %s", cfg.ConfigRefreshInterval), func() { if err := loadChecks(); err != nil { - log.Printf("Unable to refresh checks: %s", err) + logrus.WithError(err).Error("refreshing checks") } - }) + }); err != nil { + logrus.WithError(err).Fatal("registering config-refresh function") + } + c.Start() spawnChecks() - r := mux.NewRouter() - r.HandleFunc("/status", handleELBHealthCheck) - if err := http.ListenAndServe(cfg.Listen, r); err != nil { - log.Fatalf("Unable to listen: %s", err) + http.HandleFunc("/status", handleELBHealthCheck) + + server := &http.Server{ + Addr: cfg.Listen, + Handler: http.DefaultServeMux, + ReadHeaderTimeout: time.Second, + } + + if err = server.ListenAndServe(); err != nil { + logrus.WithError(err).Fatal("listening for HTTP traffic") } } -func spawnChecks() { - ctx, _ := context.WithTimeout(context.Background(), cfg.CheckInterval-time.Second) - - for id := range checks { - go executeAndRegisterCheck(ctx, id) - } -} - -func executeAndRegisterCheck(ctx context.Context, checkID string) { - check := checks[checkID] - - cmd := exec.Command("/bin/bash", "-e", "-o", "pipefail", "-c", check.Command) - cmd.Stderr = newPrefixedLogger(os.Stderr, checkID+":STDERR") - if cfg.Verbose { - cmd.Stdout = newPrefixedLogger(os.Stderr, checkID+":STDOUT") - } - err := cmd.Start() - - if err == nil { - cmdDone := make(chan error) - go func(cmdDone chan error, cmd *exec.Cmd) { cmdDone <- cmd.Wait() }(cmdDone, cmd) - loop := true - for loop { - select { - case err = <-cmdDone: - loop = false - case <-ctx.Done(): - log.Printf("Execution of check '%s' was killed through context timeout.", checkID) - cmd.Process.Kill() - time.Sleep(100 * time.Millisecond) - } - } - } - - success := err == nil - - checkResultsLock.Lock() - - if _, ok := checkResults[checkID]; !ok { - checkResults[checkID] = &checkResult{ - Check: check, - } - } - - if success == checkResults[checkID].IsSuccess { - checkResults[checkID].Streak++ - } else { - checkResults[checkID].IsSuccess = success - checkResults[checkID].Streak = 1 - } - - if !success { - log.Printf("Check %q failed, streak now at %d, error was: %s", checkID, checkResults[checkID].Streak, err) - } - - lastResultRegistered = time.Now() - - checkResultsLock.Unlock() -} - -func handleELBHealthCheck(res http.ResponseWriter, r *http.Request) { - healthy := true - start := time.Now() - buf := bytes.NewBuffer([]byte{}) +func handleELBHealthCheck(w http.ResponseWriter, _ *http.Request) { + var ( + healthy = true + start = time.Now() + buf = new(bytes.Buffer) + ) checkResultsLock.RLock() for _, cr := range checkResults { @@ -214,13 +125,15 @@ func handleELBHealthCheck(res http.ResponseWriter, r *http.Request) { } checkResultsLock.RUnlock() - res.Header().Set("X-Collection-Parsed-In", strconv.FormatInt(time.Since(start).Nanoseconds()/int64(time.Microsecond), 10)+"ms") - res.Header().Set("X-Last-Result-Registered-At", lastResultRegistered.Format(time.RFC1123)) + w.Header().Set("X-Collection-Parsed-In", strconv.FormatInt(time.Since(start).Nanoseconds()/int64(time.Microsecond), 10)+"ms") + w.Header().Set("X-Last-Result-Registered-At", lastResultRegistered.Format(time.RFC1123)) if healthy { - res.WriteHeader(http.StatusOK) + w.WriteHeader(http.StatusOK) } else { - res.WriteHeader(http.StatusInternalServerError) + w.WriteHeader(http.StatusInternalServerError) } - io.Copy(res, buf) + if _, err := io.Copy(w, buf); err != nil { + logrus.WithError(err).Error("writing HTTP response body") + } } diff --git a/prefixed_logger.go b/prefixed_logger.go deleted file mode 100644 index 3bd1f80..0000000 --- a/prefixed_logger.go +++ /dev/null @@ -1,51 +0,0 @@ -package main - -import ( - "bytes" - "fmt" - "io" - "sync" -) - -type prefixedLogger struct { - channel string - wrappedWriter io.Writer - - buffer []byte - bufferLock sync.Mutex -} - -func newPrefixedLogger(wrappedWriter io.Writer, channel string) *prefixedLogger { - return &prefixedLogger{ - channel: channel, - wrappedWriter: wrappedWriter, - buffer: []byte{}, - } -} - -func (p *prefixedLogger) dropCR(data []byte) []byte { - if len(data) > 0 && data[len(data)-1] == '\r' { - return data[0 : len(data)-1] - } - return data -} - -func (p *prefixedLogger) Write(in []byte) (n int, err error) { - p.bufferLock.Lock() - defer p.bufferLock.Unlock() - - n = len(in) - p.buffer = append(p.buffer, in...) - - for { - if i := bytes.IndexByte(p.buffer, '\n'); i >= 0 { - // We have a full newline-terminated line. - fmt.Fprintf(p.wrappedWriter, "[%s] %s\n", p.channel, string(p.dropCR(p.buffer[0:i]))) - p.buffer = p.buffer[i+1 : len(p.buffer)] - } else { - break - } - } - - return -} diff --git a/prefixed_logger_test.go b/prefixed_logger_test.go deleted file mode 100644 index dfd7840..0000000 --- a/prefixed_logger_test.go +++ /dev/null @@ -1,34 +0,0 @@ -package main - -import ( - "bytes" - "testing" -) - -func TestPrefixedLogger(t *testing.T) { - var ( - buf = bytes.NewBuffer([]byte{}) - pl = newPrefixedLogger(buf, "baum") - n int - err error - ) - - n, err = pl.Write([]byte("non-newline terminated string")) - if n != 29 || err != nil { - t.Fatalf("Write to prefixedLogger had unexpected results: n=29 != %d, err=nil != %s", n, err) - } - - if n = len(buf.Bytes()); n != 0 { - t.Fatalf("Buffer contains %d characters, should contain 0", n) - } - - pl.Write([]byte("now a newline\nand something")) - if n = len(buf.Bytes()); n != 50 { - t.Fatalf("Buffer contains %d characters, should contain 50", n) - } - - pl.Write([]byte(" more to log\nwith multiple\nnewlines\n")) - if n = len(buf.Bytes()); n != 120 { - t.Fatalf("Buffer contains %d characters, should contain 120", n) - } -}