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98 lines
3.0 KiB
Go
98 lines
3.0 KiB
Go
package driver
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import (
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"context"
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"github.com/neilotoole/sq/libsq/core/errz"
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"github.com/neilotoole/sq/libsq/core/options"
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"github.com/neilotoole/sq/libsq/core/stringz"
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)
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// OptIngestHeader specifies whether ingested data has a header row or not.
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// If not set, the ingester *may* try to detect if the input has a header.
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var OptIngestHeader = options.NewBool(
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"ingest.header",
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"",
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0,
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false,
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"Ingest data has a header row",
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`Specifies whether ingested data has a header row or not.
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If not set, the ingester *may* try to detect if the input has a header.
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Generally it is best to leave this option unset and allow the ingester
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to detect the header.`,
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options.TagSource,
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)
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// OptIngestSampleSize specifies the number of samples that a detector
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// should take to determine type.
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var OptIngestSampleSize = options.NewInt(
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"ingest.sample-size",
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"",
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0,
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256,
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"Ingest data sample size for type detection",
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`Specify the number of samples that a detector should take to determine type.`,
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options.TagSource,
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)
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// OptIngestColRename transforms a column name in ingested data.
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var OptIngestColRename = options.NewString(
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"ingest.column.rename",
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"",
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0,
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"{{.Name}}{{with .Recurrence}}_{{.}}{{end}}",
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func(s string) error {
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return stringz.ValidTemplate("ingest.column.rename", s)
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},
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"Template to rename ingest columns",
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`This Go text template is executed on ingested column names.
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Its primary purpose is to rename duplicate header column names in the
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ingested data. For example, given a CSV file with header row:
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actor_id, first_name, actor_id
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The default template renames the columns to:
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actor_id, first_name, actor_id_1
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The fields available in the template are:
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.Name column header name
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.Index zero-based index of the column in the header row
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.Alpha alphabetical index of the column, e.g. [A, B ... Z, AA, AB]
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.Recurrence nth recurrence of the colum name in the header row
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For a unique column name, e.g. "first_name" above, ".Recurrence" will be 0.
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For duplicate column names, ".Recurrence" will be 0 for the first instance,
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then 1 for the next instance, and so on.`,
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options.TagSource,
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)
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// MungeIngestColNames transforms ingest data column names, per the template
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// defined in the option driver.OptIngestColRename found on the context.
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// It is the ingest counterpart of MungeResultColNames.
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//
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// For example, given a CSV file with header [actor_id, first_name, actor_id],
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// the columns might be renamed to [actor_id, first_name, actor_id_1].
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//
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// MungeIngestColNames should be invoked by each ingester impl that may
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// encounter duplicate col names in the ingest data.
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func MungeIngestColNames(ctx context.Context, ogColNames []string) (colNames []string, err error) {
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if len(ogColNames) == 0 {
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return ogColNames, nil
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}
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o := options.FromContext(ctx)
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tplText := OptIngestColRename.Get(o)
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if tplText == "" {
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return ogColNames, nil
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}
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tpl, err := stringz.NewTemplate(OptIngestColRename.Key(), tplText)
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if err != nil {
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return nil, errz.Wrap(err, "config: ")
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}
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return doMungeColNames(tpl, ogColNames)
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}
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