helm-chart-template

Instructions

Implementation Reference

• src/tools/template.ts:24-75 (handler)

  The handler function that implements the core logic of the 'helm-chart-template' tool: fetches chart info, retrieves and decodes templates from Artifact Hub API, filters by exact filename, formats the output as text content, handles errors.

  	async ({ chartRepo, chartName, filename, version }: TemplatesParams) => {
  		try {
  			let packageId: string;
  			let chartVersion: string;
  
  			// First get the chart info
  			const chartInfo = await getChartInfo(chartRepo, chartName);
  			packageId = chartInfo.package_id;
  
  			// If version is not provided, use the latest version
  			chartVersion = version || chartInfo.version;
  
  			// Get the templates
  			const templatesResult = await getChartTemplates(
  				packageId,
  				chartVersion
  			);
  
  			// Filter templates by exact filename match
  			const filteredTemplates = templatesResult.templates.filter(
  				(template) => template.name === filename
  			);
  
  			// Format the response
  			const formattedResponse = filteredTemplates
  				.map((template) => {
  					return `--- Template: ${template.name} ---\n${template.content}\n\n`;
  				})
  				.join("");
  
  			return {
  				content: [
  					{
  						type: "text",
  						text:
  							formattedResponse ||
  							"No matching templates found for this chart",
  					},
  				],
  			};
  		} catch (error) {
  			return {
  				content: [
  					{
  						type: "text",
  						text: `Error retrieving templates: ${(error as Error).message}`,
  					},
  				],
  			};
  		}
  	}
  );

• src/tools/template.ts:11-23 (schema)

  Zod schema for input validation of the tool parameters: chartRepo, chartName, filename (required exact match), version (optional).

  {
  	chartRepo: z.string().describe("The Helm chart repository name"),
  	chartName: z.string().describe("The Helm chart name"),
  	filename: z
  		.string()
  		.describe(
  			"Exact filename (full path) to filter templates by (case-sensitive)"
  		),
  	version: z
  		.string()
  		.optional()
  		.describe("The chart version (optional, defaults to latest)"),
  },

• src/tools/template.ts:7-76 (registration)

  The registration function for the 'helm-chart-template' tool, called from index.ts, which defines the tool name, description, input schema, and handler using server.tool().

  export function registerTemplateTool(server: McpServer) {
  	return server.tool(
  		"helm-chart-template",
  		"Get the content of a template file from a Helm chart in Artifact Hub",
  		{
  			chartRepo: z.string().describe("The Helm chart repository name"),
  			chartName: z.string().describe("The Helm chart name"),
  			filename: z
  				.string()
  				.describe(
  					"Exact filename (full path) to filter templates by (case-sensitive)"
  				),
  			version: z
  				.string()
  				.optional()
  				.describe("The chart version (optional, defaults to latest)"),
  		},
  		async ({ chartRepo, chartName, filename, version }: TemplatesParams) => {
  			try {
  				let packageId: string;
  				let chartVersion: string;
  
  				// First get the chart info
  				const chartInfo = await getChartInfo(chartRepo, chartName);
  				packageId = chartInfo.package_id;
  
  				// If version is not provided, use the latest version
  				chartVersion = version || chartInfo.version;
  
  				// Get the templates
  				const templatesResult = await getChartTemplates(
  					packageId,
  					chartVersion
  				);
  
  				// Filter templates by exact filename match
  				const filteredTemplates = templatesResult.templates.filter(
  					(template) => template.name === filename
  				);
  
  				// Format the response
  				const formattedResponse = filteredTemplates
  					.map((template) => {
  						return `--- Template: ${template.name} ---\n${template.content}\n\n`;
  					})
  					.join("");
  
  				return {
  					content: [
  						{
  							type: "text",
  							text:
  								formattedResponse ||
  								"No matching templates found for this chart",
  						},
  					],
  				};
  			} catch (error) {
  				return {
  					content: [
  						{
  							type: "text",
  							text: `Error retrieving templates: ${(error as Error).message}`,
  						},
  					],
  				};
  			}
  		}
  	);
  }

• src/services/artifactHub.ts:38-46 (helper)

  Helper function to fetch basic chart information (package_id, version) from Artifact Hub API, used by the tool handler.

  export async function getChartInfo(
  	chartRepo: string,
  	chartName: string
  ): Promise<ArtifactHubPackage> {
  	const url = `https://artifacthub.io/api/v1/packages/helm/${encodeURIComponent(
  		chartRepo
  	)}/${encodeURIComponent(chartName)}`;
  	return (await fetchFromArtifactHub(url)) as ArtifactHubPackage;
  }

• src/services/artifactHub.ts:58-74 (helper)

  Helper function to fetch chart templates from Artifact Hub API, decode base64 content to UTF-8, used by the tool handler.

  export async function getChartTemplates(
  	packageId: string,
  	version: string
  ): Promise<{ templates: DecodedChartTemplate[] }> {
  	const templatesUrl = `https://artifacthub.io/api/v1/packages/${packageId}/${version}/templates`;
  	const response = (await fetchFromArtifactHub(
  		templatesUrl
  	)) as ChartTemplatesResponse;
  
  	// Decode base64 data for each template
  	return {
  		templates: response.templates.map((template) => ({
  			name: template.name,
  			content: Buffer.from(template.data, "base64").toString("utf-8"),
  		})),
  	};
  }