When trying to interact with the Zabbix-API via Powershell one might run into the problem, that an API request will not be executed successfully, but an error similar to the following one, will be displayed:

  code message         data                                                           
  ---- -------         ----                                                           
-32602 Invalid params. Invalid parameter "/1/filter/conditions": an array is expected.

Especially when using some code like in the below snippet which uses @(…) and @{…} to define data via arrays and hashtables:

function ZbxUpdateTestAction
{

    $params = @{
        body =  @{
            "jsonrpc"= "2.0"
            "method"= "action.update"
            "params"= @{
                "actionid" = "117"
                "status" = 0
                "filter" = @{
                    "evaltype" = 0
                    "conditions" = @(
                        @{
                            "conditiontype" = 4
                            "operator" = 5
                            "value"= 3
                        }
                        @{
                            "conditiontype" = 0
                            "operator" = 0
                            "value"= 435
                        }
                    )
                }
            }
            "id"= 1
            "auth" = "$api_token"
        } | ConvertTo-Json
        uri = $zbx_api_uri
        headers = @{
            "Content-Type" = "application/json"
            "Authorization" = "Bearer $api_token"
            }
        method = "Post"
    }
    $result = Invoke-WebRequest @params
    return $result.Content | ConvertFrom-Json
}

The above snippet just shows a test function to manually update an action and set conditions to send out alerts for severities of warning or higher for a specific host group.

However – when executed it will fail with the error from snippet 1.

This is because Powershell does the JSON-conversion only to a certain depth. If your structure reaches a deeper level, it will simply stop converting the dict or array which results in the above error.

Troubleshooting it, could be quite a pain in the ass as it’s not that simple to spot and when gradually extending the object it just works fine till you exceed a depth of 2.

To fix this – simple specify the depth for ConvertTo-Json

e.g.

function ZbxUpdateTestAction
{

    $params = @{
        body =  @{
            "jsonrpc"= "2.0"
            "method"= "action.update"
            "params"= @{
                "actionid" = "117"
                "status" = 0
                "filter" = @{
                    "evaltype" = 0
                    "conditions" = @(
                        @{
                            "conditiontype" = 4
                            "operator" = 5
                            "value"= 3
                        }
                        @{
                            "conditiontype" = 0
                            "operator" = 0
                            "value"= 435
                        }
                    )
                }
            }
            "id"= 1
            "auth" = "$api_token"
        } | ConvertTo-Json -Depth 5
        uri = $zbx_api_uri
        headers = @{
            "Content-Type" = "application/json"
            "Authorization" = "Bearer $api_token"
            }
        method = "Post"
    }
    $result = Invoke-WebRequest @params
    return $result.Content | ConvertFrom-Json
}

Compare line 29 between the two snippets

Refs:

• https://learn.microsoft.com/en-us/powershell/module/microsoft.powershell.utility/convertto-json?view=powershell-7.4