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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,35 @@ | ||
| :80 { | ||
| opentelemetry /myhandler { | ||
| span_name my-span | ||
| } | ||
| } | ||
| ---------- | ||
| { | ||
| "apps": { | ||
| "http": { | ||
| "servers": { | ||
| "srv0": { | ||
| "listen": [ | ||
| ":80" | ||
| ], | ||
| "routes": [ | ||
| { | ||
| "match": [ | ||
| { | ||
| "path": [ | ||
| "/myhandler" | ||
| ] | ||
| } | ||
| ], | ||
| "handle": [ | ||
| { | ||
| "span_name": "my-span", | ||
| } | ||
| ] | ||
| } | ||
| ] | ||
| } | ||
| } | ||
| } | ||
| } | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,59 @@ | ||
| # OpenTelemetry module | ||
|
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| This module provides integration with OpenTelemetry tracing facilities. It is implemented | ||
| as `caddyhttp.MiddlewareHandler` and can be chained into a list of other handlers. | ||
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| When enabled, it propagates an existing tracing context or will init a new one otherwise. | ||
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| It is based on `https://github.com/open-telemetry/opentelemetry-go`. | ||
|
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| ## Configuration | ||
|
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| ### Environment variables | ||
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| It can be configured using environment variables defined | ||
| by [spec](https://github.com/open-telemetry/opentelemetry-specification). | ||
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| IMPORTANT: Please, consider the version | ||
| of [https://github.com/open-telemetry/opentelemetry-go](https://github.com/open-telemetry/opentelemetry-go). Some parts | ||
| of the specification may be not implemented yet. | ||
|
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| Required by module environment variables are: OTEL_EXPORTER_OTLP_PROTOCOL/OTEL_EXPORTER_OTLP_TRACES_PROTOCOL and | ||
| OTEL_PROPAGATORS. | ||
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| If neither OTEL_EXPORTER_OTLP_INSECURE nor OTEL_EXPORTER_OTLP_SPAN_INSECURE is provided, then: | ||
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| 1. If OTEL_EXPORTER_OTLP_CERTIFICATE or OTEL_EXPORTER_OTLP_TRACES_CERTIFICATE are specified they will be used for TLS. | ||
| 2. Else if both OTEL_EXPORTER_OTLP_CERTIFICATE and OTEL_EXPORTER_OTLP_TRACES_CERTIFICATE are not specified, then default | ||
| TLS with the default `tls.Config` config will be used for an exporter. | ||
|
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| For the exporter configuration details, please | ||
| see [spec](https://github.com/open-telemetry/opentelemetry-specification/blob/a4440931b522c7351b0485ff4899f786b4ff4459/specification/protocol/exporter.md) | ||
| . | ||
|
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| Example: | ||
|
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| ```bash | ||
| export OTEL_EXPORTER_OTLP_HEADERS="myAuthHeader=myToken" | ||
| export OTEL_EXPORTER_OTLP_PROTOCOL=grpc | ||
| export OTEL_PROPAGATORS=tracecontext,baggage | ||
| export OTEL_EXPORTER_OTLP_SPAN_INSECURE=false | ||
| export OTEL_EXPORTER_OTLP_TRACES_ENDPOINT=localhost:12345 | ||
| ``` | ||
|
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| ### Caddy file configuration | ||
|
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| Here is an example of **Caddyfile**: | ||
|
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| ``` | ||
| handle /myHanlder { | ||
| opentelemetry { | ||
| span_name my-span | ||
| } | ||
| reverse_proxy 127.0.0.1:8081 | ||
| } | ||
| ``` | ||
|
|
||
| Please check span | ||
| naming [guideline](https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/trace/api.md#span) | ||
| . |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,123 @@ | ||
| package opentelemetry | ||
|
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| import ( | ||
| "errors" | ||
| "fmt" | ||
| "net/http" | ||
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| "github.com/caddyserver/caddy/v2" | ||
| "github.com/caddyserver/caddy/v2/caddyconfig/caddyfile" | ||
| "github.com/caddyserver/caddy/v2/caddyconfig/httpcaddyfile" | ||
| "github.com/caddyserver/caddy/v2/modules/caddyhttp" | ||
| "go.uber.org/zap" | ||
| ) | ||
|
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| func init() { | ||
| caddy.RegisterModule(OpenTelemetry{}) | ||
| httpcaddyfile.RegisterHandlerDirective("opentelemetry", parseCaddyfile) | ||
| } | ||
|
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| // OpenTelemetry implements an HTTP handler that adds support for the opentelemetry tracing. | ||
| // It is responsible for the injection and propagation of the tracing contexts. | ||
| // OpenTelemetry module can be configured via environment variables https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/sdk-environment-variables.md. Some values can be overwritten with values from the configuration file. | ||
| type OpenTelemetry struct { | ||
| // SpanName is a span name. It SHOULD follow the naming guideline https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/trace/api.md#span | ||
| SpanName string `json:"span_name"` | ||
|
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| // otel implements opentelemetry related logic. | ||
| otel openTelemetryWrapper | ||
|
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| logger *zap.Logger | ||
| } | ||
|
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| // CaddyModule returns the Caddy module information. | ||
| func (OpenTelemetry) CaddyModule() caddy.ModuleInfo { | ||
| return caddy.ModuleInfo{ | ||
| ID: "http.handlers.opentelemetry", | ||
| New: func() caddy.Module { return new(OpenTelemetry) }, | ||
| } | ||
| } | ||
|
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| // Provision implements caddy.Provisioner. | ||
| func (ot *OpenTelemetry) Provision(ctx caddy.Context) error { | ||
| ot.logger = ctx.Logger(ot) | ||
|
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| var err error | ||
| ot.otel, err = newOpenTelemetryWrapper(ctx, ot.SpanName) | ||
|
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| return err | ||
| } | ||
|
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| // Cleanup implements caddy.CleanerUpper and closes any idle connections. It calls Shutdown method for a trace provider https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/trace/sdk.md#shutdown. | ||
| func (ot *OpenTelemetry) Cleanup() error { | ||
| if err := ot.otel.cleanup(ot.logger); err != nil { | ||
| return fmt.Errorf("tracerProvider shutdown: %w", err) | ||
| } | ||
| return nil | ||
| } | ||
|
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| // Validate implements caddy.Validator. | ||
| func (ot *OpenTelemetry) Validate() error { | ||
| if ot.otel.tracer == nil { | ||
| return errors.New("openTelemetry tracer is nil") | ||
| } | ||
|
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| return nil | ||
| } | ||
|
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| // ServeHTTP implements caddyhttp.MiddlewareHandler. | ||
| func (ot *OpenTelemetry) ServeHTTP(w http.ResponseWriter, r *http.Request, next caddyhttp.Handler) error { | ||
| return ot.otel.ServeHTTP(w, r, next) | ||
| } | ||
|
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| // UnmarshalCaddyfile sets up the module from Caddyfile tokens. | ||
| func (ot *OpenTelemetry) UnmarshalCaddyfile(d *caddyfile.Dispenser) error { | ||
| setParameter := func(d *caddyfile.Dispenser, val *string) error { | ||
| if d.NextArg() { | ||
| *val = d.Val() | ||
| } else { | ||
| return d.ArgErr() | ||
| } | ||
| if d.NextArg() { | ||
| return d.ArgErr() | ||
| } | ||
| return nil | ||
| } | ||
|
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| // paramsMap is a mapping between "string" parameter from the Caddyfile and its destination within the module | ||
| paramsMap := map[string]*string{ | ||
| "span_name": &ot.SpanName, | ||
| } | ||
|
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| for d.Next() { | ||
| args := d.RemainingArgs() | ||
| if len(args) > 0 { | ||
| return d.ArgErr() | ||
| } | ||
|
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| for d.NextBlock(0) { | ||
| if dst, ok := paramsMap[d.Val()]; ok { | ||
| if err := setParameter(d, dst); err != nil { | ||
| return err | ||
| } | ||
| } else { | ||
| return d.ArgErr() | ||
| } | ||
| } | ||
| } | ||
| return nil | ||
| } | ||
|
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| func parseCaddyfile(h httpcaddyfile.Helper) (caddyhttp.MiddlewareHandler, error) { | ||
| var m OpenTelemetry | ||
| err := m.UnmarshalCaddyfile(h.Dispenser) | ||
| return &m, err | ||
| } | ||
|
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| // Interface guards | ||
| var ( | ||
| _ caddy.Provisioner = (*OpenTelemetry)(nil) | ||
| _ caddy.Validator = (*OpenTelemetry)(nil) | ||
| _ caddyhttp.MiddlewareHandler = (*OpenTelemetry)(nil) | ||
| _ caddyfile.Unmarshaler = (*OpenTelemetry)(nil) | ||
| ) |
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