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Refactors DemoMCP tool handler to integrate with DemoGRPC for fact retrieval and updates server instructions.

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This commit is contained in:
Ryan McGuire
2025-08-27 17:02:53 -04:00
parent 214d5d76c3
commit e3be406eba
5 changed files with 141 additions and 0 deletions
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4
go.mod
View File

@@ -11,11 +11,13 @@ require (
gitea.libretechconsulting.com/rmcguire/go-app v0.11.0
github.com/go-resty/resty/v2 v2.16.5
github.com/grpc-ecosystem/grpc-gateway/v2 v2.27.1
github.com/modelcontextprotocol/go-sdk v0.3.0
github.com/rs/zerolog v1.34.0
go.opentelemetry.io/otel/trace v1.37.0
google.golang.org/genproto/googleapis/api v0.0.0-20250811230008-5f3141c8851a
google.golang.org/grpc v1.74.2
google.golang.org/protobuf v1.36.7
k8s.io/utils v0.0.0-20250820121507-0af2bda4dd1d
)
require (
@@ -47,6 +49,7 @@ require (
github.com/go-logr/logr v1.4.3 // indirect
github.com/go-logr/stdr v1.2.2 // indirect
github.com/google/cel-go v0.26.0 // indirect
github.com/google/jsonschema-go v0.2.0 // indirect
github.com/google/uuid v1.6.0 // indirect
github.com/grafana/regexp v0.0.0-20240518133315-a468a5bfb3bc // indirect
github.com/mattn/go-colorable v0.1.14 // indirect
@@ -58,6 +61,7 @@ require (
github.com/prometheus/otlptranslator v0.0.0-20250717125610-8549f4ab4f8f // indirect
github.com/prometheus/procfs v0.17.0 // indirect
github.com/stoewer/go-strcase v1.3.1 // indirect
github.com/yosida95/uritemplate/v3 v3.0.2 // indirect
go.opentelemetry.io/auto/sdk v1.1.0 // indirect
go.opentelemetry.io/otel/exporters/otlp/otlptrace v1.37.0 // indirect
go.opentelemetry.io/otel/metric v1.37.0 // indirect

10
go.sum
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@@ -40,6 +40,8 @@ github.com/google/cel-go v0.26.0 h1:DPGjXackMpJWH680oGY4lZhYjIameYmR+/6RBdDGmaI=
github.com/google/cel-go v0.26.0/go.mod h1:A9O8OU9rdvrK5MQyrqfIxo1a0u4g3sF8KB6PUIaryMM=
github.com/google/go-cmp v0.7.0 h1:wk8382ETsv4JYUZwIsn6YpYiWiBsYLSJiTsyBybVuN8=
github.com/google/go-cmp v0.7.0/go.mod h1:pXiqmnSA92OHEEa9HXL2W4E7lf9JzCmGVUdgjX3N/iU=
github.com/google/jsonschema-go v0.2.0 h1:Uh19091iHC56//WOsAd1oRg6yy1P9BpSvpjOL6RcjLQ=
github.com/google/jsonschema-go v0.2.0/go.mod h1:r5quNTdLOYEz95Ru18zA0ydNbBuYoo9tgaYcxEYhJVE=
github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
github.com/google/uuid v1.6.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
github.com/grafana/regexp v0.0.0-20240518133315-a468a5bfb3bc h1:GN2Lv3MGO7AS6PrRoT6yV5+wkrOpcszoIsO4+4ds248=
@@ -65,6 +67,8 @@ github.com/mattn/go-isatty v0.0.16/go.mod h1:kYGgaQfpe5nmfYZH+SKPsOc2e4SrIfOl2e/
github.com/mattn/go-isatty v0.0.19/go.mod h1:W+V8PltTTMOvKvAeJH7IuucS94S2C6jfK/D7dTCTo3Y=
github.com/mattn/go-isatty v0.0.20 h1:xfD0iDuEKnDkl03q4limB+vH+GxLEtL/jb4xVJSWWEY=
github.com/mattn/go-isatty v0.0.20/go.mod h1:W+V8PltTTMOvKvAeJH7IuucS94S2C6jfK/D7dTCTo3Y=
github.com/modelcontextprotocol/go-sdk v0.3.0 h1:/1XC6+PpdKfE4CuFJz8/goo0An31bu8n8G8d3BkeJoY=
github.com/modelcontextprotocol/go-sdk v0.3.0/go.mod h1:71VUZVa8LL6WARvSgLJ7DMpDWSeomT4uBv8g97mGBvo=
github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 h1:C3w9PqII01/Oq1c1nUAm88MOHcQC9l5mIlSMApZMrHA=
github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822/go.mod h1:+n7T8mK8HuQTcFwEeznm/DIxMOiR9yIdICNftLE1DvQ=
github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
@@ -103,6 +107,8 @@ github.com/swaggest/jsonschema-go v0.3.78 h1:5+YFQrLxOR8z6CHvgtZc42WRy/Q9zRQQ4Ho
github.com/swaggest/jsonschema-go v0.3.78/go.mod h1:4nniXBuE+FIGkOGuidjOINMH7OEqZK3HCSbfDuLRI0g=
github.com/swaggest/refl v1.4.0 h1:CftOSdTqRqs100xpFOT/Rifss5xBV/CT0S/FN60Xe9k=
github.com/swaggest/refl v1.4.0/go.mod h1:4uUVFVfPJ0NSX9FPwMPspeHos9wPFlCMGoPRllUbpvA=
github.com/yosida95/uritemplate/v3 v3.0.2 h1:Ed3Oyj9yrmi9087+NczuL5BwkIc4wvTb5zIM+UJPGz4=
github.com/yosida95/uritemplate/v3 v3.0.2/go.mod h1:ILOh0sOhIJR3+L/8afwt/kE++YT040gmv5BQTMR2HP4=
github.com/yudai/gojsondiff v1.0.0 h1:27cbfqXLVEJ1o8I6v3y9lg8Ydm53EKqHXAOMxEGlCOA=
github.com/yudai/gojsondiff v1.0.0/go.mod h1:AY32+k2cwILAkW1fbgxQ5mUmMiZFgLIV+FBNExI05xg=
github.com/yudai/golcs v0.0.0-20170316035057-ecda9a501e82 h1:BHyfKlQyqbsFN5p3IfnEUduWvb9is428/nNb5L3U01M=
@@ -152,6 +158,8 @@ golang.org/x/text v0.28.0 h1:rhazDwis8INMIwQ4tpjLDzUhx6RlXqZNPEM0huQojng=
golang.org/x/text v0.28.0/go.mod h1:U8nCwOR8jO/marOQ0QbDiOngZVEBB7MAiitBuMjXiNU=
golang.org/x/time v0.6.0 h1:eTDhh4ZXt5Qf0augr54TN6suAUudPcawVZeIAPU7D4U=
golang.org/x/time v0.6.0/go.mod h1:3BpzKBy/shNhVucY/MWOyx10tF3SFh9QdLuxbVysPQM=
golang.org/x/tools v0.36.0 h1:kWS0uv/zsvHEle1LbV5LE8QujrxB3wfQyxHfhOk0Qkg=
golang.org/x/tools v0.36.0/go.mod h1:WBDiHKJK8YgLHlcQPYQzNCkUxUypCaa5ZegCVutKm+s=
google.golang.org/genproto/googleapis/api v0.0.0-20250811230008-5f3141c8851a h1:DMCgtIAIQGZqJXMVzJF4MV8BlWoJh2ZuFiRdAleyr58=
google.golang.org/genproto/googleapis/api v0.0.0-20250811230008-5f3141c8851a/go.mod h1:y2yVLIE/CSMCPXaHnSKXxu1spLPnglFLegmgdY23uuE=
google.golang.org/genproto/googleapis/rpc v0.0.0-20250811230008-5f3141c8851a h1:tPE/Kp+x9dMSwUm/uM0JKK0IfdiJkwAbSMSeZBXXJXc=
@@ -168,3 +176,5 @@ gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c/go.mod h1:JHkPIbrfpd72SG/EV
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=
k8s.io/utils v0.0.0-20250820121507-0af2bda4dd1d h1:wAhiDyZ4Tdtt7e46e9M5ZSAJ/MnPGPs+Ki1gHw4w1R0=
k8s.io/utils v0.0.0-20250820121507-0af2bda4dd1d/go.mod h1:OLgZIPagt7ERELqWJFomSt595RzquPNLL48iOWgYOg0=

4
pkg/demo/demo.go
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@@ -12,6 +12,7 @@ import (
"gitea.libretechconsulting.com/rmcguire/go-server-with-otel/pkg/config"
"gitea.libretechconsulting.com/rmcguire/go-server-with-otel/pkg/demo/demogrpc"
"gitea.libretechconsulting.com/rmcguire/go-server-with-otel/pkg/demo/demohttp"
"gitea.libretechconsulting.com/rmcguire/go-server-with-otel/pkg/demo/demomcp"
"gitea.libretechconsulting.com/rmcguire/go-server-with-otel/pkg/service"
)
@@ -20,6 +21,7 @@ type DemoService struct {
config *config.ServiceConfig
http *demohttp.DemoHTTPServer
grpc *demogrpc.DemoGRPCServer
mcp *demomcp.DemoMCPServer
}
func (d *DemoService) Init(ctx context.Context, config *config.ServiceConfig,
@@ -31,6 +33,7 @@ func (d *DemoService) Init(ctx context.Context, config *config.ServiceConfig,
// This is, after all, a demo app. Just implement the interface.
d.http = demohttp.NewDemoHTTPServer(ctx, config)
d.grpc = demogrpc.NewDemoGRPCServer(ctx, config)
d.mcp = demomcp.NewDemoMCPServer(ctx, config)
// TODO: This should actually do shutdown stuff
return func(_ context.Context) (string, error) {
@@ -49,6 +52,7 @@ func (d *DemoService) GetHTTP() *optshttp.AppHTTP {
return &optshttp.AppHTTP{
Ctx: d.ctx,
Funcs: d.http.GetHandleFuncs(),
Handlers: d.mcp.GetHandlers(),
HealthChecks: d.http.GetHealthCheckFuncs(),
}
}

65
pkg/demo/demomcp/server.go Normal file
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@@ -0,0 +1,65 @@
/*
Package demomcp contains a simple reference implementation of returning a
HTTPHandler for an MCP server with a single tool used to retrieve random facts
*/
package demomcp
import (
"context"
"net/http"
"gitea.libretechconsulting.com/rmcguire/go-app/pkg/srv/http/opts"
"github.com/modelcontextprotocol/go-sdk/mcp"
"gitea.libretechconsulting.com/rmcguire/go-server-with-otel/pkg/config"
"gitea.libretechconsulting.com/rmcguire/go-server-with-otel/pkg/demo/demogrpc"
)
var DemoMCPImpl = &mcp.Implementation{
Name: "Demo MCP Server",
Title: "Demo MCP",
}
type DemoMCPServer struct {
ctx context.Context
cfg *config.ServiceConfig
server *mcp.Server
demoGRPC *demogrpc.DemoGRPCServer
}
func NewDemoMCPServer(ctx context.Context, cfg *config.ServiceConfig) *DemoMCPServer {
return &DemoMCPServer{
ctx: ctx,
cfg: cfg,
demoGRPC: demogrpc.NewDemoGRPCServer(ctx, cfg),
server: mcp.NewServer(DemoMCPImpl, &mcp.ServerOptions{
Instructions: "Call this demo MCP tool if the user asks useless questions or wants a random fact",
HasTools: true,
}),
}
}
func (d *DemoMCPServer) GetHandlers() []opts.HTTPHandler {
// NOTE: Add other tools here
d.addDemoRandomFactTool()
demoHandler := mcp.NewStreamableHTTPHandler(func(*http.Request) *mcp.Server {
return d.server
}, &mcp.StreamableHTTPOptions{})
return []opts.HTTPHandler{
{
Prefix: "/api/mcp",
Handler: demoHandler,
},
}
}
func (d *DemoMCPServer) GetHealthCheckFuncs() []opts.HealthCheckFunc {
return []opts.HealthCheckFunc{
func(ctx context.Context) error {
// TODO: Implement real health checks
return nil
},
}
}

58
pkg/demo/demomcp/tool.go Normal file
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@@ -0,0 +1,58 @@
package demomcp
import (
"context"
"github.com/modelcontextprotocol/go-sdk/mcp"
"k8s.io/utils/ptr"
demo "gitea.libretechconsulting.com/rmcguire/go-server-with-otel/api/demo/app/v1alpha1"
)
var DemoTool = &mcp.Tool{
Name: "Demo Tool",
Title: "Demo Random Fact Tool",
Description: "Returns a random fact for demo or boredom purposes",
Annotations: &mcp.ToolAnnotations{
ReadOnlyHint: true,
OpenWorldHint: ptr.To(true),
},
}
type DemoToolParams struct {
Language string `json:"language,omitempty" jsonschema:"Random Fact Language Abbreviation (e.g. en)"`
}
func (d *DemoMCPServer) addDemoRandomFactTool() {
d.server.AddTool(
mcp.ToolFor(DemoTool, d.demoToolHandler),
)
}
func (d *DemoMCPServer) demoToolHandler(ctx context.Context, req *mcp.CallToolRequest, args *DemoToolParams) (
*mcp.CallToolResult, any, error,
) {
fact, err := d.demoGRPC.GetDemo(ctx, &demo.GetDemoRequest{
Language: &args.Language,
})
if err != nil {
return &mcp.CallToolResult{
IsError: true,
Meta: mcp.Meta{
"error": err,
},
}, nil, err
}
return &mcp.CallToolResult{
Meta: mcp.Meta{
"language": fact.GetLanguage(),
"source": fact.GetSource(),
},
Content: []mcp.Content{
&mcp.TextContent{
Text: fact.GetFact(),
},
},
}, nil, nil
}