Azure Logic Apps消耗计划转标准计划：变量迁移方案咨询

1. ARM模板部署时预计算变量（优先推荐） #

利用ARM模板的表达式能力，在部署阶段就计算好所有变量值，直接注入到逻辑应用的应用设置中。这样connections.json或工作流里只需直接引用@appsetting('变量名')即可，无需在运行时计算。

示例ARM模板片段：

{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "parameters": {
    "environment": {
      "type": "string",
      "allowedValues": ["d", "t", "p"]
    }
  },
  "variables": {
    "give_dev_when_test": "[if(equals(parameters('environment'), 't'), 'd', parameters('environment'))]",
    "resource_name_prefix": "[concat('abc-', parameters('environment'), '-common')]",
    "key_vault_name": "[concat('abc-', variables('give_dev_when_test'), '-common-kv')]"
  },
  "resources": [
    {
      "type": "Microsoft.Logic/workflows",
      "apiVersion": "2019-05-01",
      "name": "your-standard-logic-app",
      "location": "[resourceGroup().location]",
      "properties": {
        "state": "Enabled"
      },
      "resources": [
        {
          "type": "configurations",
          "apiVersion": "2019-05-01",
          "name": "appsettings",
          "dependsOn": ["[resourceId('Microsoft.Logic/workflows', 'your-standard-logic-app')]"],
          "properties": {
            "Environment": "[parameters('environment')]",
            "GiveDevWhenTest": "[variables('give_dev_when_test')]",
            "ResourceNamePrefix": "[variables('resource_name_prefix')]",
            "KeyVaultName": "[variables('key_vault_name')]"
          }
        }
      ]
    }
  ]
}

部署后，在connections.json中直接引用：

{
  "managedApiConnections": {
    "keyvault": {
      "api": {
        "id": "/subscriptions/{subId}/providers/Microsoft.Web/locations/{location}/managedApis/keyvault"
      },
      "connection": {
        "id": "/subscriptions/{subId}/resourceGroups/{rg}/providers/Microsoft.Web/connections/keyvault"
      },
      "connectionProperties": {
        "authentication": {
          "type": "ManagedServiceIdentity"
        }
      },
      "parameters": {
        "vaultName": "@appsetting('KeyVaultName')"
      }
    }
  }
}

适用场景：变量值由部署参数决定，无需运行时动态变更的场景。

2. 封装共享变量到Azure Functions #

将变量计算逻辑封装到Azure Function中，逻辑应用通过HTTP触发调用该Function获取计算后的变量值。这种方式既避免了在每个工作流中重复定义变量，也支持复杂的表达式和内部引用。

示例Function代码（C#）：

public static class VariableFunction
{
    [FunctionName("GetLogicAppVariables")]
    public static async Task<IActionResult> Run(
        [HttpTrigger(AuthorizationLevel.Function, "get", Route = null)] HttpRequest req,
        ILogger log)
    {
        string environment = req.Query["environment"];
        string giveDevWhenTest = environment == "t" ? "d" : environment;
        string resourceNamePrefix = $"abc-{environment}-common";
        string keyVaultName = $"abc-{giveDevWhenTest}-common-kv";

        var variables = new {
            give_dev_when_test = giveDevWhenTest,
            resource_name_prefix = resourceNamePrefix,
            key_vault_name = keyVaultName
        };

        return new OkObjectResult(variables);
    }
}

在逻辑应用中调用该Function，将返回的变量存储到工作流级变量中（仅需在工作流开头调用一次，后续步骤复用），或者直接在需要的步骤中引用返回值：

"actions": {
  "Get_Variables": {
    "type": "Http",
    "inputs": {
      "method": "GET",
      "uri": "https://your-function-app.azurewebsites.net/api/GetLogicAppVariables?environment=@appsetting('Environment')",
      "authentication": {
        "type": "ManagedServiceIdentity"
      }
    },
    "runAfter": {}
  },
  "Use_KeyVault_Name": {
    "type": "ApiConnection",
    "inputs": {
      "host": {
        "connection": {
          "name": "@parameters('$connections')['keyvault']['connectionId']"
        }
      },
      "method": "get",
      "path": "/secrets/{secretName}",
      "parameters": {
        "secretName": "your-secret",
        "vaultName": "@body('Get_Variables')?['key_vault_name']"
      }
    },
    "runAfter": {
      "Get_Variables": [
        "Succeeded"
      ]
    }
  }
}

适用场景：变量需要运行时动态计算，或多个逻辑应用需要复用同一套变量逻辑的场景。

3. 创建共享变量工作流（轻量替代方案） #

如果不想额外部署Azure Functions，可以创建一个专门的“变量服务”工作流，其他工作流通过逻辑应用的内置HTTP触发器调用该工作流获取变量值。

共享工作流示例：

{
  "definition": {
    "$schema": "https://schema.management.azure.com/providers/Microsoft.Logic/schemas/2016-06-01/workflowdefinition.json#",
    "actions": {
      "Initialize_Variables": {
        "type": "InitializeVariable",
        "inputs": {
          "variables": [
            {
              "name": "give_dev_when_test",
              "type": "string",
              "value": "@if(equals(appsetting('Environment'), 't'), 'd', appsetting('Environment'))"
            },
            {
              "name": "resource_name_prefix",
              "type": "string",
              "value": "@concat('abc-', appsetting('Environment'), '-common')"
            },
            {
              "name": "key_vault_name",
              "type": "string",
              "value": "@concat('abc-', variables('give_dev_when_test'), '-common-kv')"
            }
          ]
        },
        "runAfter": {}
      },
      "Return_Variables": {
        "type": "Response",
        "inputs": {
          "statusCode": 200,
          "body": {
            "give_dev_when_test": "@variables('give_dev_when_test')",
            "resource_name_prefix": "@variables('resource_name_prefix')",
            "key_vault_name": "@variables('key_vault_name')"
          }
        },
        "runAfter": {
          "Initialize_Variables": [
            "Succeeded"
          ]
        }
      }
    },
    "triggers": {
      "manual": {
        "type": "Request",
        "kind": "Http",
        "inputs": {
          "schema": {}
        }
      }
    },
    "contentVersion": "1.0.0.0"
  }
}

其他工作流通过HTTP调用该共享工作流，获取变量值后复用。

适用场景：已有逻辑应用标准计划环境，不想引入额外服务的轻量场景。

内容的提问来源于stack exchange，提问作者arung